# Release Notes¶

## NumPy 1.17.0 Release Notes¶

### Highlights¶

- Experimental support for overriding numpy functions is now always available,
see
`__array_function__`

below. - NumPy’s FFT implementation has switched to pocketfft

### New functions¶

### Deprecations¶

`np.polynomial`

functions warn when passed `float`

in place of `int`

¶

Previously functions in this module would accept `float`

values provided they
were integral (`1.0`

, `2.0`

, etc). For consistency with the rest of numpy,
doing so is now deprecated, and in future will raise a `TypeError`

.

Similarly, passing a float like `0.5`

in place of an integer will now raise a
`TypeError`

instead of the previous `ValueError`

.

#### Deprecate `numpy.distutils.exec_command`

and `numpy.distutils.temp_file_name`

¶

The internal use of these functions has been refactored and there are better
alternatives. Relace `exec_command`

with `subprocess.Popen`

and
`temp_file_name`

with `tempfile.mkstemp`

.

### Future Changes¶

### Expired deprecations¶

### Compatibility notes¶

#### float16 subnormal rounding¶

Casting from a different floating point precision to float16 used incorrect rounding in some edge cases. This means in rare cases, subnormal results will now be rounded up instead of down, changing the last bit (ULP) of the result.

#### Signed zero when using divmod¶

Starting in version 1.12.0, numpy incorrectly returned a negatively signed zero
when using the `divmod`

and `floor_divide`

functions when the result was
zero. For example:

```
>>> np.zeros(10)//1
array([-0., -0., -0., -0., -0., -0., -0., -0., -0., -0.])
```

With this release, the result is correctly returned as a positively signed zero:

```
>>> np.zeros(10)//1
array([0., 0., 0., 0., 0., 0., 0., 0., 0., 0.])
```

#### Do not lookup `__buffer__`

attribute in `numpy.frombuffer`

¶

Looking up `__buffer__`

attribute in `numpy.frombuffer`

was undocumented and
non-functional. This code was removed. If needed, use
`frombuffer(memoryview(obj), ...)`

instead.

`out``is buffered for memory overlaps in ``np.take`

, `np.choose`

, `np.put`

¶

If the out argument to these functions is provided and has memory overlap with the other arguments, it is now buffered to avoid order-dependent behavior.

#### Unpickling while loading requires explicit opt-in¶

The functions `np.load`

, and `np.lib.format.read_array`

take an
*allow_pickle* keyword which now defaults to `False`

in response to
CVE-2019-6446.

### C API changes¶

### New Features¶

#### Timsort has replaced mergesort as the stable sorting implementation¶

Timsort has been implemented and is now used in place of mergesort. Due to the
need to maintain backward compatibility, the sorting `kind`

options `"stable"`

and `"mergesort"`

have been made aliases of each other with the actual sort
implementation used a function of the array type. Timsort features improved
performace on already or nearly sorted data and performs like mergesort on
random data. The algorithm is stable and requires O(n/2) working space. For
details of the algorithm, refer to
CPython listsort.txt.

`np.unpackbits`

now accepts a `count`

parameter¶

`count`

allows subsetting the number of bits that will be unpacked up-front,
rather than reshaping and subsetting later, making the `packbits`

operation
invertible, and the unpacking less wasteful. Counts larger than the number of
available bits add zero padding. Negative counts trim bits off the end instead
of counting from the beginning. None counts implement the existing behavior of
unpacking everything.

`np.linalg.svd`

and `np.linalg.pinv`

can be faster on hermitian inputs¶

These functions now accept a `hermitian`

argument, matching the one added
to `np.linalg.matrix_rank`

in 1.14.0.

#### divmod operation is now supported for two `timedelta64`

operands¶

The divmod operator now handles two `np.timedelta64`

operands, with
type signature mm->qm.

#### New mode “empty” for `np.pad`

¶

This mode pads an array to a desired shape without initializing the new entries.

### Improvements¶

#### Array comparison assertions include maximum differences¶

Error messages from array comparison tests such as
*np.testing.assert_allclose* now include “max absolute difference” and
“max relative difference,” in addition to the previous “mismatch” percentage.
This information makes it easier to update absolute and relative error
tolerances.

#### Replacement of the *fftpack*-based FFT module by the *pocketfft* library¶

Both implementations have the same ancestor (Fortran77 *FFTPACK* by Paul N.
Swarztrauber), but *pocketfft* contains additional modifications which
improve both accuracy and performance in some circumstances. For FFT lengths
containing large prime factors, *pocketfft* uses Bluestein’s algorithm, which
maintains *O(N log N)* run time complexity instead of deteriorating towards
*O(N*N)* for prime lengths. Also, accuracy for real-valued FFTs with near-prime
lengths has improved and is on par with complex-valued FFTs.

#### Further improvements to `ctypes`

support in `np.ctypeslib`

¶

A new `numpy.ctypeslib.as_ctypes_type`

function has been added, which can be
used to converts a *dtype* into a best-guess `ctypes`

type. Thanks to this
new function, `numpy.ctypeslib.as_ctypes`

now supports a much wider range of
array types, including structures, booleans, and integers of non-native
endianness.

`numpy.errstate`

is now also function decorator¶

Currently, if you have a function like:

```
def foo():
pass
```

and you want to wrap the whole thing in *errstate*, you have to rewrite it like so:

```
def foo():
with np.errstate(...):
pass
```

but with this change, you can do:

```
@np.errstate(...)
def foo():
pass
```

thereby saving a level of indentation

#### Improve performance of `np.pad`

¶

The performance of the function has been improved for most cases by filling in a preallocated array with the desired padded shape instead of using concatenation.

`np.interp`

handles infinities more robustly¶

In some cases where `np.interp`

would previously return `np.nan`

, it now
returns an appropriate infinity.

#### Specialized `np.isnan`

, `np.isinf`

, and `np.isfinite`

ufuncs for bool and int types¶

The boolean and integer types are incapable of storing `np.nan`

and `np.inf`

values,
which allows us to provide specialized ufuncs that are up to 250x faster than the current
approach.

#### New keywords added to `np.nan_to_num`

¶

`np.nan_to_num`

now accepts keywords `nan`

, `posinf`

and `neginf`

allowing the
user to define the value to replace the `nan`

, positive and negative `np.inf`

values
respectively.

### Changes¶

`median`

and `percentile`

family of functions no longer warn about `nan`

¶

`numpy.median`

, `numpy.percentile`

, and `numpy.quantile`

used to emit a
`RuntimeWarning`

when encountering an `numpy.nan`

. Since they return the
`nan`

value, the warning is redundant and has been removed.

`timedelta64 % 0`

behavior adjusted to return `NaT`

¶

The modulus operation with two `np.timedelta64`

operands now returns
`NaT`

in the case of division by zero, rather than returning zero

#### NumPy functions now always support overrides with `__array_function__`

¶

NumPy now always checks the `__array_function__`

method to implement overrides
of NumPy functions on non-NumPy arrays, as described in NEP 18. The feature
was available for testing with NumPy 1.16 if appropriate environment variables
are set, but is now always enabled.

`__array_interface__`

offset now works as documented¶

The interface may use an `offset`

value that was mistakenly ignored.

## NumPy 1.16.2 Release Notes¶

NumPy 1.16.2 is a quick release fixing several problems encountered on Windows. The Python versions supported are 2.7 and 3.5-3.7. The Windows problems addressed are:

- DLL load problems for NumPy wheels on Windows,
- distutils command line parsing on Windows.

There is also a regression fix correcting signed zeros produced by divmod, see below for details.

Downstream developers building this release should use Cython >= 0.29.2 and, if using OpenBLAS, OpenBLAS > v0.3.4.

If you are installing using pip, you may encounter a problem with older
installed versions of NumPy that pip did not delete becoming mixed with the
current version, resulting in an `ImportError`

. That problem is particularly
common on Debian derived distributions due to a modified pip. The fix is to
make sure all previous NumPy versions installed by pip have been removed. See
#12736 for discussion of the
issue.

### Compatibility notes¶

#### Signed zero when using divmod¶

Starting in version 1.12.0, numpy incorrectly returned a negatively signed zero
when using the `divmod`

and `floor_divide`

functions when the result was
zero. For example:

```
>>> np.zeros(10)//1
array([-0., -0., -0., -0., -0., -0., -0., -0., -0., -0.])
```

With this release, the result is correctly returned as a positively signed zero:

```
>>> np.zeros(10)//1
array([0., 0., 0., 0., 0., 0., 0., 0., 0., 0.])
```

### Contributors¶

A total of 5 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Eric Wieser
- Matti Picus
- Tyler Reddy
- Tony LaTorre +

### Pull requests merged¶

A total of 7 pull requests were merged for this release.

- #12909: TST: fix vmImage dispatch in Azure
- #12923: MAINT: remove complicated test of multiarray import failure mode
- #13020: BUG: fix signed zero behavior in npy_divmod
- #13026: MAINT: Add functions to parse shell-strings in the platform-native…
- #13028: BUG: Fix regression in parsing of F90 and F77 environment variables
- #13038: BUG: parse shell escaping in extra_compile_args and extra_link_args
- #13041: BLD: Windows absolute path DLL loading

## NumPy 1.16.1 Release Notes¶

The NumPy 1.16.1 release fixes bugs reported against the 1.16.0 release, and also backports several enhancements from master that seem appropriate for a release series that is the last to support Python 2.7. The wheels on PyPI are linked with OpenBLAS v0.3.4+, which should fix the known threading issues found in previous OpenBLAS versions.

Downstream developers building this release should use Cython >= 0.29.2 and, if using OpenBLAS, OpenBLAS > v0.3.4.

If you are installing using pip, you may encounter a problem with older
installed versions of NumPy that pip did not delete becoming mixed with the
current version, resulting in an `ImportError`

. That problem is particularly
common on Debian derived distributions due to a modified pip. The fix is to
make sure all previous NumPy versions installed by pip have been removed. See
#12736 for discussion of the
issue. Note that previously this problem resulted in an `AttributeError`

.

### Contributors¶

A total of 16 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Antoine Pitrou
- Arcesio Castaneda Medina +
- Charles Harris
- Chris Markiewicz +
- Christoph Gohlke
- Christopher J. Markiewicz +
- Daniel Hrisca +
- EelcoPeacs +
- Eric Wieser
- Kevin Sheppard
- Matti Picus
- OBATA Akio +
- Ralf Gommers
- Sebastian Berg
- Stephan Hoyer
- Tyler Reddy

### Enhancements¶

- #12767: ENH: add mm->q floordiv
- #12768: ENH: port np.core.overrides to C for speed
- #12769: ENH: Add np.ctypeslib.as_ctypes_type(dtype), improve
*np.ctypeslib.as_ctypes* - #12773: ENH: add “max difference” messages to np.testing.assert_array_equal…
- #12820: ENH: Add mm->qm divmod
- #12890: ENH: add _dtype_ctype to namespace for freeze analysis

### Compatibility notes¶

- The changed error message emited by array comparison testing functions may affect doctests. See below for detail.
- Casting from double and single denormals to float16 has been corrected. In some rare cases, this may result in results being rounded up instead of down, changing the last bit (ULP) of the result.

### New Features¶

#### divmod operation is now supported for two `timedelta64`

operands¶

The divmod operator now handles two `np.timedelta64`

operands, with
type signature `mm->qm`

.

### Improvements¶

#### Further improvements to `ctypes`

support in `np.ctypeslib`

¶

A new `numpy.ctypeslib.as_ctypes_type`

function has been added, which can be
used to converts a *dtype* into a best-guess `ctypes`

type. Thanks to this
new function, `numpy.ctypeslib.as_ctypes`

now supports a much wider range of
array types, including structures, booleans, and integers of non-native
endianness.

#### Array comparison assertions include maximum differences¶

Error messages from array comparison tests such as
*np.testing.assert_allclose* now include “max absolute difference” and
“max relative difference,” in addition to the previous “mismatch” percentage.
This information makes it easier to update absolute and relative error
tolerances.

## NumPy 1.16.0 Release Notes¶

This NumPy release is the last one to support Python 2.7 and will be maintained as a long term release with bug fixes until 2020. Support for Python 3.4 been dropped, the supported Python versions are 2.7 and 3.5-3.7. The wheels on PyPI are linked with OpenBLAS v0.3.4+, which should fix the known threading issues found in previous OpenBLAS versions.

Downstream developers building this release should use Cython >= 0.29 and, if using OpenBLAS, OpenBLAS > v0.3.4.

This release has seen a lot of refactoring and features many bug fixes, improved code organization, and better cross platform compatibility. Not all of these improvements will be visible to users, but they should help make maintenance easier going forward.

### Highlights¶

- Experimental (opt-in only) support for overriding numpy functions,
see
`__array_function__`

below. - The
`matmul`

function is now a ufunc. This provides better performance and allows overriding with`__array_ufunc__`

. - Improved support for the ARM and POWER architectures.
- Improved support for AIX and PyPy.
- Improved interop with ctypes.
- Improved support for PEP 3118.

### New functions¶

New functions added to the

*numpy.lib.recfuntions*module to ease the structured assignment changes:`assign_fields_by_name`

`structured_to_unstructured`

`unstructured_to_structured`

`apply_along_fields`

`require_fields`

See the user guide at <https://docs.scipy.org/doc/numpy/user/basics.rec.html> for more info.

### New deprecations¶

- The type dictionaries
`numpy.core.typeNA`

and`numpy.core.sctypeNA`

are deprecated. They were buggy and not documented and will be removed in the 1.18 release. Use`numpy.sctypeDict` instead. - The
`numpy.asscalar`

function is deprecated. It is an alias to the more powerful`numpy.ndarray.item`

, not tested, and fails for scalars. - The
*numpy.set_array_ops*and*numpy.get_array_ops*functions are deprecated. As part of*NEP 15*, they have been deprecated along with the C-API functions`PyArray_SetNumericOps`

and`PyArray_GetNumericOps`

. Users who wish to override the inner loop functions in built-in ufuncs should use`PyUFunc_ReplaceLoopBySignature`

. - The
`numpy.unravel_index`

keyword argument`dims`

is deprecated, use`shape`

instead. - The
`numpy.histogram`

`normed`

argument is deprecated. It was deprecated previously, but no warning was issued. - The
`positive`

operator (`+`

) applied to non-numerical arrays is deprecated. See below for details. - Passing an iterator to the stack functions is deprecated

### Expired deprecations¶

- NaT comparisons now return
`False`

without a warning, finishing a deprecation cycle begun in NumPy 1.11. `np.lib.function_base.unique`

was removed, finishing a deprecation cycle begun in NumPy 1.4. Use`numpy.unique`

instead.- multi-field indexing now returns views instead of copies, finishing a deprecation cycle begun in NumPy 1.7. The change was previously attempted in NumPy 1.14 but reverted until now.
`np.PackageLoader`

and`np.pkgload`

have been removed. These were deprecated in 1.10, had no tests, and seem to no longer work in 1.15.

### Future changes¶

- NumPy 1.17 will drop support for Python 2.7.

### Compatibility notes¶

#### f2py script on Windows¶

On Windows, the installed script for running f2py is now an `.exe`

file
rather than a `*.py`

file and should be run from the command line as `f2py`

whenever the `Scripts`

directory is in the path. Running `f2py`

as a module
`python -m numpy.f2py [...]`

will work without path modification in any
version of NumPy.

#### NaT comparisons¶

Consistent with the behavior of NaN, all comparisons other than inequality
checks with datetime64 or timedelta64 NaT (“not-a-time”) values now always
return `False`

, and inequality checks with NaT now always return `True`

.
This includes comparisons beteween NaT values. For compatibility with the
old behavior, use `np.isnat`

to explicitly check for NaT or convert
datetime64/timedelta64 arrays with `.astype(np.int64)`

before making
comparisons.

#### complex64/128 alignment has changed¶

The memory alignment of complex types is now the same as a C-struct composed of
two floating point values, while before it was equal to the size of the type.
For many users (for instance on x64/unix/gcc) this means that complex64 is now
4-byte aligned instead of 8-byte aligned. An important consequence is that
aligned structured dtypes may now have a different size. For instance,
`np.dtype('c8,u1', align=True)`

used to have an itemsize of 16 (on x64/gcc)
but now it is 12.

More in detail, the complex64 type now has the same alignment as a C-struct
`struct {float r, i;}`

, according to the compiler used to compile numpy, and
similarly for the complex128 and complex256 types.

#### nd_grid __len__ removal¶

`len(np.mgrid)`

and `len(np.ogrid)`

are now considered nonsensical
and raise a `TypeError`

.

`np.unravel_index`

now accepts `shape`

keyword argument¶

Previously, only the `dims`

keyword argument was accepted
for specification of the shape of the array to be used
for unraveling. `dims`

remains supported, but is now deprecated.

#### multi-field views return a view instead of a copy¶

Indexing a structured array with multiple fields, e.g., `arr[['f1', 'f3']]`

,
returns a view into the original array instead of a copy. The returned view
will often have extra padding bytes corresponding to intervening fields in the
original array, unlike before, which will affect code such as
`arr[['f1', 'f3']].view('float64')`

. This change has been planned since numpy
1.7. Operations hitting this path have emitted `FutureWarnings`

since then.
Additional `FutureWarnings`

about this change were added in 1.12.

To help users update their code to account for these changes, a number of
functions have been added to the `numpy.lib.recfunctions`

module which
safely allow such operations. For instance, the code above can be replaced
with `structured_to_unstructured(arr[['f1', 'f3']], dtype='float64')`

.
See the “accessing multiple fields” section of the
user guide.

### C API changes¶

The `NPY_API_VERSION`

was incremented to 0x0000D, due to the addition
of:

`PyUFuncObject.core_dim_flags`

`PyUFuncObject.core_dim_sizes`

`PyUFuncObject.identity_value`

`PyUFunc_FromFuncAndDataAndSignatureAndIdentity`

### New Features¶

#### Integrated squared error (ISE) estimator added to `histogram`

¶

This method (`bins='stone'`

) for optimizing the bin number is a
generalization of the Scott’s rule. The Scott’s rule assumes the distribution
is approximately Normal, while the ISE is a non-parametric method based on
cross-validation.

`max_rows`

keyword added for `np.loadtxt`

¶

New keyword `max_rows`

in `numpy.loadtxt`

sets the maximum rows of the
content to be read after `skiprows`

, as in `numpy.genfromtxt`

.

#### modulus operator support added for `np.timedelta64`

operands¶

The modulus (remainder) operator is now supported for two operands
of type `np.timedelta64`

. The operands may have different units
and the return value will match the type of the operands.

### Improvements¶

#### no-copy pickling of numpy arrays¶

Up to protocol 4, numpy array pickling created 2 spurious copies of the data
being serialized. With pickle protocol 5, and the `PickleBuffer`

API, a
large variety of numpy arrays can now be serialized without any copy using
out-of-band buffers, and with one less copy using in-band buffers. This
results, for large arrays, in an up to 66% drop in peak memory usage.

#### build shell independence¶

NumPy builds should no longer interact with the host machine
shell directly. `exec_command`

has been replaced with
`subprocess.check_output`

where appropriate.

*np.polynomial.Polynomial* classes render in LaTeX in Jupyter notebooks¶

When used in a front-end that supports it, *Polynomial* instances are now
rendered through LaTeX. The current format is experimental, and is subject to
change.

`randint`

and `choice`

now work on empty distributions¶

Even when no elements needed to be drawn, `np.random.randint`

and
`np.random.choice`

raised an error when the arguments described an empty
distribution. This has been fixed so that e.g.
`np.random.choice([], 0) == np.array([], dtype=float64)`

.

`linalg.lstsq`

, `linalg.qr`

, and `linalg.svd`

now work with empty arrays¶

Previously, a `LinAlgError`

would be raised when an empty matrix/empty
matrices (with zero rows and/or columns) is/are passed in. Now outputs of
appropriate shapes are returned.

#### Chain exceptions to give better error messages for invalid PEP3118 format strings¶

This should help track down problems.

#### Einsum optimization path updates and efficiency improvements¶

Einsum was synchronized with the current upstream work.

`numpy.angle`

and `numpy.expand_dims`

now work on `ndarray`

subclasses¶

In particular, they now work for masked arrays.

`NPY_NO_DEPRECATED_API`

compiler warning suppression¶

Setting `NPY_NO_DEPRECATED_API`

to a value of 0 will suppress the current compiler
warnings when the deprecated numpy API is used.

`np.diff`

Added kwargs prepend and append¶

New kwargs `prepend`

and `append`

, allow for values to be inserted on
either end of the differences. Similar to options for *ediff1d*. Now the
inverse of *cumsum* can be obtained easily via `prepend=0`

.

#### ARM support updated¶

Support for ARM CPUs has been updated to accommodate 32 and 64 bit targets, and also big and little endian byte ordering. AARCH32 memory alignment issues have been addressed. CI testing has been expanded to include AARCH64 targets via the services of shippable.com.

#### Appending to build flags¶

`numpy.distutils`

has always overridden rather than appended to *LDFLAGS* and
other similar such environment variables for compiling Fortran extensions.
Now, if the *NPY_DISTUTILS_APPEND_FLAGS* environment variable is set to 1, the
behavior will be appending. This applied to: *LDFLAGS*, *F77FLAGS*,
*F90FLAGS*, *FREEFLAGS*, *FOPT*, *FDEBUG*, and *FFLAGS*. See gh-11525 for more
details.

#### Generalized ufunc signatures now allow fixed-size dimensions¶

By using a numerical value in the signature of a generalized ufunc, one can
indicate that the given function requires input or output to have dimensions
with the given size. E.g., the signature of a function that converts a polar
angle to a two-dimensional cartesian unit vector would be `()->(2)`

; that
for one that converts two spherical angles to a three-dimensional unit vector
would be `(),()->(3)`

; and that for the cross product of two
three-dimensional vectors would be `(3),(3)->(3)`

.

Note that to the elementary function these dimensions are not treated any differently from variable ones indicated with a name starting with a letter; the loop still is passed the corresponding size, but it can now count on that size being equal to the fixed one given in the signature.

#### Generalized ufunc signatures now allow flexible dimensions¶

Some functions, in particular numpy’s implementation of `@`

as `matmul`

,
are very similar to generalized ufuncs in that they operate over core
dimensions, but one could not present them as such because they were able to
deal with inputs in which a dimension is missing. To support this, it is now
allowed to postfix a dimension name with a question mark to indicate that the
dimension does not necessarily have to be present.

With this addition, the signature for `matmul`

can be expressed as
`(m?,n),(n,p?)->(m?,p?)`

. This indicates that if, e.g., the second operand
has only one dimension, for the purposes of the elementary function it will be
treated as if that input has core shape `(n, 1)`

, and the output has the
corresponding core shape of `(m, 1)`

. The actual output array, however, has
the flexible dimension removed, i.e., it will have shape `(..., m)`

.
Similarly, if both arguments have only a single dimension, the inputs will be
presented as having shapes `(1, n)`

and `(n, 1)`

to the elementary
function, and the output as `(1, 1)`

, while the actual output array returned
will have shape `()`

. In this way, the signature allows one to use a
single elementary function for four related but different signatures,
`(m,n),(n,p)->(m,p)`

, `(n),(n,p)->(p)`

, `(m,n),(n)->(m)`

and
`(n),(n)->()`

.

`np.clip`

and the `clip`

method check for memory overlap¶

The `out`

argument to these functions is now always tested for memory overlap
to avoid corrupted results when memory overlap occurs.

#### New value `unscaled`

for option `cov`

in `np.polyfit`

¶

A further possible value has been added to the `cov`

parameter of the
`np.polyfit`

function. With `cov='unscaled'`

the scaling of the covariance
matrix is disabled completely (similar to setting `absolute_sigma=True`

in
`scipy.optimize.curve_fit`

). This would be useful in occasions, where the
weights are given by 1/sigma with sigma being the (known) standard errors of
(Gaussian distributed) data points, in which case the unscaled matrix is
already a correct estimate for the covariance matrix.

#### Detailed docstrings for scalar numeric types¶

The `help`

function, when applied to numeric types such as `numpy.intc`

,
`numpy.int_`

, and `numpy.longlong`

, now lists all of the aliased names for that
type, distinguishing between platform -dependent and -independent aliases.

`__module__`

attribute now points to public modules¶

The `__module__`

attribute on most NumPy functions has been updated to refer
to the preferred public module from which to access a function, rather than
the module in which the function happens to be defined. This produces more
informative displays for functions in tools such as IPython, e.g., instead of
`<function 'numpy.core.fromnumeric.sum'>`

you now see
`<function 'numpy.sum'>`

.

#### Large allocations marked as suitable for transparent hugepages¶

On systems that support transparent hugepages over the madvise system call
numpy now marks that large memory allocations can be backed by hugepages which
reduces page fault overhead and can in some fault heavy cases improve
performance significantly. On Linux the setting for huge pages to be used,
*/sys/kernel/mm/transparent_hugepage/enabled*, must be at least *madvise*.
Systems which already have it set to *always* will not see much difference as
the kernel will automatically use huge pages where appropriate.

Users of very old Linux kernels (~3.x and older) should make sure that
*/sys/kernel/mm/transparent_hugepage/defrag* is not set to *always* to avoid
performance problems due concurrency issues in the memory defragmentation.

#### Alpine Linux (and other musl c library distros) support¶

We now default to use *fenv.h* for floating point status error reporting.
Previously we had a broken default that sometimes would not report underflow,
overflow, and invalid floating point operations. Now we can support non-glibc
distrubutions like Alpine Linux as long as they ship *fenv.h*.

#### Speedup `np.block`

for large arrays¶

Large arrays (greater than `512 * 512`

) now use a blocking algorithm based on
copying the data directly into the appropriate slice of the resulting array.
This results in significant speedups for these large arrays, particularly for
arrays being blocked along more than 2 dimensions.

`arr.ctypes.data_as(...)`

holds a reference to arr¶

Previously the caller was responsible for keeping the array alive for the lifetime of the pointer.

#### Speedup `np.take`

for read-only arrays¶

The implementation of `np.take`

no longer makes an unnecessary copy of the
source array when its `writeable`

flag is set to `False`

.

#### Support path-like objects for more functions¶

The `np.core.records.fromfile`

function now supports `pathlib.Path`

and other path-like objects in addition to a file object. Furthermore, the
`np.load`

function now also supports path-like objects when using memory
mapping (`mmap_mode`

keyword argument).

#### Better behaviour of ufunc identities during reductions¶

Universal functions have an `.identity`

which is used when `.reduce`

is
called on an empty axis.

As of this release, the logical binary ufuncs, *logical_and*, *logical_or*,
and *logical_xor*, now have `identity`

s of type *bool*, where previously they
were of type *int*. This restores the 1.14 behavior of getting `bool`

s when
reducing empty object arrays with these ufuncs, while also keeping the 1.15
behavior of getting `int`

s when reducing empty object arrays with arithmetic
ufuncs like `add`

and `multiply`

.

Additionally, *logaddexp* now has an identity of `-inf`

, allowing it to be
called on empty sequences, where previously it could not be.

This is possible thanks to the new
`PyUFunc_FromFuncAndDataAndSignatureAndIdentity`

, which allows
arbitrary values to be used as identities now.

#### Improved conversion from ctypes objects¶

Numpy has always supported taking a value or type from `ctypes`

and
converting it into an array or dtype, but only behaved correctly for simpler
types. As of this release, this caveat is lifted - now:

- The
`_pack_`

attribute of`ctypes.Structure`

, used to emulate C’s`__attribute__((packed))`

, is respected. - Endianness of all ctypes objects is preserved
`ctypes.Union`

is supported- Non-representable constructs raise exceptions, rather than producing
dangerously incorrect results:
- Bitfields are no longer interpreted as sub-arrays
- Pointers are no longer replaced with the type that they point to

#### A new `ndpointer.contents`

member¶

This matches the `.contents`

member of normal ctypes arrays, and can be used
to construct an `np.array`

around the pointers contents. This replaces
`np.array(some_nd_pointer)`

, which stopped working in 1.15. As a side effect
of this change, `ndpointer`

now supports dtypes with overlapping fields and
padding.

`matmul`

is now a `ufunc`

¶

`numpy.matmul`

is now a ufunc which means that both the function and the
`__matmul__`

operator can now be overridden by `__array_ufunc__`

. Its
implementation has also changed. It uses the same BLAS routines as
`numpy.dot`

, ensuring its performance is similar for large matrices.

#### Start and stop arrays for `linspace`

, `logspace`

and `geomspace`

¶

These functions used to be limited to scalar stop and start values, but can now take arrays, which will be properly broadcast and result in an output which has one axis prepended. This can be used, e.g., to obtain linearly interpolated points between sets of points.

#### CI extended with additional services¶

We now use additional free CI services, thanks to the companies that provide:

- Codecoverage testing via codecov.io
- Arm testing via shippable.com
- Additional test runs on azure pipelines

These are in addition to our continued use of travis, appveyor (for wheels) and LGTM

### Changes¶

#### Comparison ufuncs will now error rather than return NotImplemented¶

Previously, comparison ufuncs such as `np.equal`

would return
*NotImplemented* if their arguments had structured dtypes, to help comparison
operators such as `__eq__`

deal with those. This is no longer needed, as the
relevant logic has moved to the comparison operators proper (which thus do
continue to return *NotImplemented* as needed). Hence, like all other ufuncs,
the comparison ufuncs will now error on structured dtypes.

#### Positive will now raise a deprecation warning for non-numerical arrays¶

Previously, `+array`

unconditionally returned a copy. Now, it will
raise a `DeprecationWarning`

if the array is not numerical (i.e.,
if `np.positive(array)`

raises a `TypeError`

. For `ndarray`

subclasses that override the default `__array_ufunc__`

implementation,
the `TypeError`

is passed on.

`NDArrayOperatorsMixin`

now implements matrix multiplication¶

Previously, `np.lib.mixins.NDArrayOperatorsMixin`

did not implement the
special methods for Python’s matrix multiplication operator (`@`

). This has
changed now that `matmul`

is a ufunc and can be overridden using
`__array_ufunc__`

.

#### The scaling of the covariance matrix in `np.polyfit`

is different¶

So far, `np.polyfit`

used a non-standard factor in the scaling of the the
covariance matrix. Namely, rather than using the standard `chisq/(M-N)`

, it
scaled it with `chisq/(M-N-2)`

where M is the number of data points and N is the
number of parameters. This scaling is inconsistent with other fitting programs
such as e.g. `scipy.optimize.curve_fit`

and was changed to `chisq/(M-N)`

.

`maximum`

and `minimum`

no longer emit warnings¶

As part of code introduced in 1.10, `float32`

and `float64`

set invalid
float status when a Nan is encountered in `numpy.maximum`

and `numpy.minimum`

,
when using SSE2 semantics. This caused a *RuntimeWarning* to sometimes be
emitted. In 1.15 we fixed the inconsistencies which caused the warnings to
become more conspicuous. Now no warnings will be emitted.

#### Umath and multiarray c-extension modules merged into a single module¶

The two modules were merged, according to NEP 15. Previously *np.core.umath*
and *np.core.multiarray* were seperate c-extension modules. They are now python
wrappers to the single *np.core/_multiarray_math* c-extension module.

`getfield`

validity checks extended¶

`numpy.ndarray.getfield`

now checks the dtype and offset arguments to prevent
accessing invalid memory locations.

#### NumPy functions now support overrides with `__array_function__`

¶

NumPy has a new experimental mechanism for overriding the implementation of
almost all NumPy functions on non-NumPy arrays by defining an
`__array_function__`

method, as described in NEP 18.

This feature is not yet been enabled by default, but has been released to facilitate experimentation by potential users. See the NEP for details on setting the appropriate environment variable. We expect the NumPy 1.17 release will enable overrides by default, which will also be more performant due to a new implementation written in C.

#### Arrays based off readonly buffers cannot be set `writeable`

¶

We now disallow setting the `writeable`

flag True on arrays created
from `fromstring(readonly-buffer)`

.

## NumPy 1.15.4 Release Notes¶

This is a bugfix release for bugs and regressions reported following the 1.15.3 release. The Python versions supported by this release are 2.7, 3.4-3.7. The wheels are linked with OpenBLAS v0.3.0, which should fix some of the linalg problems reported for NumPy 1.14.

### Compatibility Note¶

The NumPy 1.15.x OS X wheels released on PyPI no longer contain 32-bit binaries. That will also be the case in future releases. See #11625 for the related discussion. Those needing 32-bit support should look elsewhere or build from source.

### Contributors¶

A total of 4 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Matti Picus
- Sebastian Berg
- bbbbbbbbba +

## NumPy 1.15.3 Release Notes¶

This is a bugfix release for bugs and regressions reported following the 1.15.2 release. The Python versions supported by this release are 2.7, 3.4-3.7. The wheels are linked with OpenBLAS v0.3.0, which should fix some of the linalg problems reported for NumPy 1.14.

### Compatibility Note¶

The NumPy 1.15.x OS X wheels released on PyPI no longer contain 32-bit binaries. That will also be the case in future releases. See #11625 for the related discussion. Those needing 32-bit support should look elsewhere or build from source.

### Contributors¶

A total of 7 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Charles Harris
- Jeroen Demeyer
- Kevin Sheppard
- Matthew Bowden +
- Matti Picus
- Tyler Reddy

### Pull requests merged¶

A total of 12 pull requests were merged for this release.

- #12080: MAINT: Blacklist some MSVC complex functions.
- #12083: TST: Add azure CI testing to 1.15.x branch.
- #12084: BUG: test_path() now uses Path.resolve()
- #12085: TST, MAINT: Fix some failing tests on azure-pipelines mac and…
- #12187: BUG: Fix memory leak in mapping.c
- #12188: BUG: Allow boolean subtract in histogram
- #12189: BUG: Fix in-place permutation
- #12190: BUG: limit default for get_num_build_jobs() to 8
- #12191: BUG: OBJECT_to_* should check for errors
- #12192: DOC: Prepare for NumPy 1.15.3 release.
- #12237: BUG: Fix MaskedArray fill_value type conversion.
- #12238: TST: Backport azure-pipeline testing fixes for Mac

## NumPy 1.15.2 Release Notes¶

This is a bugfix release for bugs and regressions reported following the 1.15.1 release.

- The matrix PendingDeprecationWarning is now suppressed in pytest 3.8.
- The new cached allocations machinery has been fixed to be thread safe.
- The boolean indexing of subclasses now works correctly.
- A small memory leak in PyArray_AdaptFlexibleDType has been fixed.

The Python versions supported by this release are 2.7, 3.4-3.7. The wheels are linked with OpenBLAS v0.3.0, which should fix some of the linalg problems reported for NumPy 1.14.

### Compatibility Note¶

The NumPy 1.15.x OS X wheels released on PyPI no longer contain 32-bit binaries. That will also be the case in future releases. See #11625 for the related discussion. Those needing 32-bit support should look elsewhere or build from source.

### Contributors¶

A total of 4 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Julian Taylor
- Marten van Kerkwijk
- Matti Picus

### Pull requests merged¶

A total of 4 pull requests were merged for this release.

## NumPy 1.15.1 Release Notes¶

This is a bugfix release for bugs and regressions reported following the 1.15.0 release.

- The annoying but harmless RuntimeWarning that “numpy.dtype size changed” has been suppressed. The long standing suppression was lost in the transition to pytest.
- The update to Cython 0.28.3 exposed a problematic use of a gcc attribute used to prefer code size over speed in module initialization, possibly resulting in incorrect compiled code. This has been fixed in latest Cython but has been disabled here for safety.
- Support for big-endian and ARMv8 architectures has been improved.

The Python versions supported by this release are 2.7, 3.4-3.7. The wheels are linked with OpenBLAS v0.3.0, which should fix some of the linalg problems reported for NumPy 1.14.

### Compatibility Note¶

### Contributors¶

A total of 7 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Chris Billington
- Elliott Sales de Andrade +
- Eric Wieser
- Jeremy Manning +
- Matti Picus
- Ralf Gommers

### Pull requests merged¶

A total of 24 pull requests were merged for this release.

- #11647: MAINT: Filter Cython warnings in
`__init__.py`

- #11648: BUG: Fix doc source links to unwrap decorators
- #11657: BUG: Ensure singleton dimensions are not dropped when converting…
- #11661: BUG: Warn on Nan in minimum,maximum for scalars
- #11665: BUG: cython sometimes emits invalid gcc attribute
- #11682: BUG: Fix regression in void_getitem
- #11698: BUG: Make matrix_power again work for object arrays.
- #11700: BUG: Add missing PyErr_NoMemory after failing malloc
- #11719: BUG: Fix undefined functions on big-endian systems.
- #11720: MAINT: Make einsum optimize default to False.
- #11746: BUG: Fix regression in loadtxt for bz2 text files in Python 2.
- #11757: BUG: Revert use of
*console_scripts*. - #11758: BUG: Fix Fortran kind detection for aarch64 & s390x.
- #11759: BUG: Fix printing of longdouble on ppc64le.
- #11760: BUG: Fixes for unicode field names in Python 2
- #11761: BUG: Increase required cython version on python 3.7
- #11763: BUG: check return value of _buffer_format_string
- #11775: MAINT: Make assert_array_compare more generic.
- #11776: TST: Fix urlopen stubbing.
- #11777: BUG: Fix regression in intersect1d.
- #11779: BUG: Fix test sensitive to platform byte order.
- #11781: BUG: Avoid signed overflow in histogram
- #11785: BUG: Fix pickle and memoryview for datetime64, timedelta64 scalars
- #11786: BUG: Deprecation triggers segfault

## NumPy 1.15.0 Release Notes¶

NumPy 1.15.0 is a release with an unusual number of cleanups, many deprecations of old functions, and improvements to many existing functions. Please read the detailed descriptions below to see if you are affected.

For testing, we have switched to pytest as a replacement for the no longer maintained nose framework. The old nose based interface remains for downstream projects who may still be using it.

The Python versions supported by this release are 2.7, 3.4-3.7. The wheels are linked with OpenBLAS v0.3.0, which should fix some of the linalg problems reported for NumPy 1.14.

### Highlights¶

- NumPy has switched to pytest for testing.
- A new
`numpy.printoptions`

context manager. - Many improvements to the histogram functions.
- Support for unicode field names in python 2.7.
- Improved support for PyPy.
- Fixes and improvements to
`numpy.einsum`

.

### New functions¶

`numpy.gcd`

and`numpy.lcm`

, to compute the greatest common divisor and least common multiple.`numpy.ma.stack`

, the`numpy.stack`

array-joining function generalized to masked arrays.`numpy.quantile`

function, an interface to`percentile`

without factors of 100`numpy.nanquantile`

function, an interface to`nanpercentile`

without factors of 100`numpy.printoptions`

, a context manager that sets print options temporarily for the scope of the`with`

block:>>> with np.printoptions(precision=2): ... print(np.array([2.0]) / 3) [0.67]

`numpy.histogram_bin_edges`

, a function to get the edges of the bins used by a histogram without needing to calculate the histogram.C functions

*npy_get_floatstatus_barrier*and*npy_clear_floatstatus_barrier*have been added to deal with compiler optimization changing the order of operations. See below for details.

### Deprecations¶

- Aliases of builtin
`pickle`

functions are deprecated, in favor of their unaliased`pickle.<func>`

names:`numpy.loads`

`numpy.core.numeric.load`

`numpy.core.numeric.loads`

`numpy.ma.loads`

,`numpy.ma.dumps`

`numpy.ma.load`

,`numpy.ma.dump`

- these functions already failed on python 3 when called with a string.

- Multidimensional indexing with anything but a tuple is deprecated. This means
that the index list in
`ind = [slice(None), 0]; arr[ind]`

should be changed to a tuple, e.g.,`ind = [slice(None), 0]; arr[tuple(ind)]`

or`arr[(slice(None), 0)]`

. That change is necessary to avoid ambiguity in expressions such as`arr[[[0, 1], [0, 1]]]`

, currently interpreted as`arr[array([0, 1]), array([0, 1])]`

, that will be interpreted as`arr[array([[0, 1], [0, 1]])]`

in the future. - Imports from the following sub-modules are deprecated, they will be removed
at some future date.
`numpy.testing.utils`

`numpy.testing.decorators`

`numpy.testing.nosetester`

*numpy.testing.noseclasses*`numpy.core.umath_tests`

- Giving a generator to
`numpy.sum`

is now deprecated. This was undocumented behavior, but worked. Previously, it would calculate the sum of the generator expression. In the future, it might return a different result. Use`np.sum(np.from_iter(generator))`

or the built-in Python`sum`

instead. - Users of the C-API should call
`PyArrayResolveWriteBackIfCopy`

or`PyArray_DiscardWritbackIfCopy`

on any array with the`WRITEBACKIFCOPY`

flag set, before deallocating the array. A deprecation warning will be emitted if those calls are not used when needed. - Users of
`nditer`

should use the nditer object as a context manager anytime one of the iterator operands is writeable, so that numpy can manage writeback semantics, or should call`it.close()`

. A*RuntimeWarning*may be emitted otherwise in these cases. - The
`normed`

argument of`np.histogram`

, deprecated long ago in 1.6.0, now emits a`DeprecationWarning`

.

### Future Changes¶

- NumPy 1.16 will drop support for Python 3.4.
- NumPy 1.17 will drop support for Python 2.7.

### Compatibility notes¶

#### Compiled testing modules renamed and made private¶

The following compiled modules have been renamed and made private:

`umath_tests`

->`_umath_tests`

`test_rational`

->`_rational_tests`

`multiarray_tests`

->`_multiarray_tests`

`struct_ufunc_test`

->`_struct_ufunc_tests`

`operand_flag_tests`

->`_operand_flag_tests`

The `umath_tests`

module is still available for backwards compatibility, but
will be removed in the future.

#### The `NpzFile`

returned by `np.savez`

is now a `collections.abc.Mapping`

¶

This means it behaves like a readonly dictionary, and has a new `.values()`

method and `len()`

implementation.

For python 3, this means that `.iteritems()`

, `.iterkeys()`

have been
deprecated, and `.keys()`

and `.items()`

now return views and not lists.
This is consistent with how the builtin `dict`

type changed between python 2
and python 3.

#### Under certain conditions, `nditer`

must be used in a context manager¶

When using an `numpy.nditer`

with the `"writeonly"`

or `"readwrite"`

flags, there
are some circumstances where nditer doesn’t actually give you a view of the
writable array. Instead, it gives you a copy, and if you make changes to the
copy, nditer later writes those changes back into your actual array. Currently,
this writeback occurs when the array objects are garbage collected, which makes
this API error-prone on CPython and entirely broken on PyPy. Therefore,
`nditer`

should now be used as a context manager whenever it is used
with writeable arrays, e.g., `with np.nditer(...) as it: ...`

. You may also
explicitly call `it.close()`

for cases where a context manager is unusable,
for instance in generator expressions.

#### Numpy has switched to using pytest instead of nose for testing¶

The last nose release was 1.3.7 in June, 2015, and development of that tool has
ended, consequently NumPy has now switched to using pytest. The old decorators
and nose tools that were previously used by some downstream projects remain
available, but will not be maintained. The standard testing utilities,
`assert_almost_equal`

and such, are not be affected by this change except for
the nose specific functions `import_nose`

and `raises`

. Those functions are
not used in numpy, but are kept for downstream compatibility.

#### Numpy no longer monkey-patches `ctypes`

with `__array_interface__`

¶

Previously numpy added `__array_interface__`

attributes to all the integer
types from `ctypes`

.

`np.ma.notmasked_contiguous`

and `np.ma.flatnotmasked_contiguous`

always return lists¶

This is the documented behavior, but previously the result could be any of slice, None, or list.

All downstream users seem to check for the `None`

result from
`flatnotmasked_contiguous`

and replace it with `[]`

. Those callers will
continue to work as before.

`np.squeeze`

restores old behavior of objects that cannot handle an `axis`

argument¶

Prior to version `1.7.0`

, `numpy.squeeze`

did not have an `axis`

argument and
all empty axes were removed by default. The incorporation of an `axis`

argument made it possible to selectively squeeze single or multiple empty axes,
but the old API expectation was not respected because axes could still be
selectively removed (silent success) from an object expecting all empty axes to
be removed. That silent, selective removal of empty axes for objects expecting
the old behavior has been fixed and the old behavior restored.

#### unstructured void array’s `.item`

method now returns a bytes object¶

`.item`

now returns a `bytes`

object instead of a buffer or byte array.
This may affect code which assumed the return value was mutable, which is no
longer the case.

`copy.copy`

and `copy.deepcopy`

no longer turn `masked`

into an array¶

Since `np.ma.masked`

is a readonly scalar, copying should be a no-op. These
functions now behave consistently with `np.copy()`

.

#### Multifield Indexing of Structured Arrays will still return a copy¶

The change that multi-field indexing of structured arrays returns a view
instead of a copy is pushed back to 1.16. A new method
`numpy.lib.recfunctions.repack_fields`

has been introduced to help mitigate
the effects of this change, which can be used to write code compatible with
both numpy 1.15 and 1.16. For more information on how to update code to account
for this future change see the “accessing multiple fields” section of the
user guide.

### C API changes¶

#### New functions `npy_get_floatstatus_barrier`

and `npy_clear_floatstatus_barrier`

¶

Functions `npy_get_floatstatus_barrier`

and `npy_clear_floatstatus_barrier`

have been added and should be used in place of the ```
npy_get_floatstatus``and
``npy_clear_status
```

functions. Optimizing compilers like GCC 8.1 and Clang
were rearranging the order of operations when the previous functions were used
in the ufunc SIMD functions, resulting in the floatstatus flags being checked
before the operation whose status we wanted to check was run. See #10339.

#### Changes to `PyArray_GetDTypeTransferFunction`

¶

`PyArray_GetDTypeTransferFunction`

now defaults to using user-defined
`copyswapn`

/ `copyswap`

for user-defined dtypes. If this causes a
significant performance hit, consider implementing `copyswapn`

to reflect the
implementation of `PyArray_GetStridedCopyFn`

. See #10898.

### New Features¶

`np.gcd`

and `np.lcm`

ufuncs added for integer and objects types¶

These compute the greatest common divisor, and lowest common multiple,
respectively. These work on all the numpy integer types, as well as the
builtin arbitrary-precision `Decimal`

and `long`

types.

#### Support for cross-platform builds for iOS¶

The build system has been modified to add support for the
`_PYTHON_HOST_PLATFORM`

environment variable, used by `distutils`

when
compiling on one platform for another platform. This makes it possible to
compile NumPy for iOS targets.

This only enables you to compile NumPy for one specific platform at a time. Creating a full iOS-compatible NumPy package requires building for the 5 architectures supported by iOS (i386, x86_64, armv7, armv7s and arm64), and combining these 5 compiled builds products into a single “fat” binary.

`return_indices`

keyword added for `np.intersect1d`

¶

New keyword `return_indices`

returns the indices of the two input arrays
that correspond to the common elements.

`np.quantile`

and `np.nanquantile`

¶

Like `np.percentile`

and `np.nanpercentile`

, but takes quantiles in [0, 1]
rather than percentiles in [0, 100]. `np.percentile`

is now a thin wrapper
around `np.quantile`

with the extra step of dividing by 100.

#### Build system¶

Added experimental support for the 64-bit RISC-V architecture.

### Improvements¶

`np.einsum`

updates¶

Syncs einsum path optimization tech between `numpy`

and *opt_einsum*. In
particular, the *greedy* path has received many enhancements by @jcmgray. A
full list of issues fixed are:

- Arbitrary memory can be passed into the
*greedy*path. Fixes gh-11210. - The greedy path has been updated to contain more dynamic programming ideas preventing a large number of duplicate (and expensive) calls that figure out the actual pair contraction that takes place. Now takes a few seconds on several hundred input tensors. Useful for matrix product state theories.
- Reworks the broadcasting dot error catching found in gh-11218 gh-10352 to be a bit earlier in the process.
- Enhances the
*can_dot*functionality that previous missed an edge case (part of gh-11308).

`np.flip`

can operate over multiple axes¶

`np.flip`

now accepts None, or tuples of int, in its `axis`

argument. If
axis is None, it will flip over all the axes.

`histogram`

and `histogramdd`

functions have moved to `np.lib.histograms`

¶

These were originally found in `np.lib.function_base`

. They are still
available under their un-scoped `np.histogram(dd)`

names, and
to maintain compatibility, aliased at `np.lib.function_base.histogram(dd)`

.

Code that does `from np.lib.function_base import *`

will need to be updated
with the new location, and should consider not using `import *`

in future.

`histogram`

will accept NaN values when explicit bins are given¶

Previously it would fail when trying to compute a finite range for the data. Since the range is ignored anyway when the bins are given explicitly, this error was needless.

Note that calling `histogram`

on NaN values continues to raise the
`RuntimeWarning`

s typical of working with nan values, which can be silenced
as usual with `errstate`

.

`histogram`

works on datetime types, when explicit bin edges are given¶

Dates, times, and timedeltas can now be histogrammed. The bin edges must be passed explicitly, and are not yet computed automatically.

`histogram`

“auto” estimator handles limited variance better¶

No longer does an IQR of 0 result in `n_bins=1`

, rather the number of bins
chosen is related to the data size in this situation.

#### The edges retuned by *histogram`* and `histogramdd`

now match the data float type¶

When passed `np.float16`

, `np.float32`

, or `np.longdouble`

data, the
returned edges are now of the same dtype. Previously, `histogram`

would only
return the same type if explicit bins were given, and `histogram`

would
produce `float64`

bins no matter what the inputs.

`histogramdd`

allows explicit ranges to be given in a subset of axes¶

The `range`

argument of `numpy.histogramdd`

can now contain `None`

values to
indicate that the range for the corresponding axis should be computed from the
data. Previously, this could not be specified on a per-axis basis.

#### The normed arguments of `histogramdd`

and `histogram2d`

have been renamed¶

These arguments are now called `density`

, which is consistent with
`histogram`

. The old argument continues to work, but the new name should be
preferred.

`np.r_`

works with 0d arrays, and `np.ma.mr_`

works with `np.ma.masked`

¶

0d arrays passed to the *r_* and *mr_* concatenation helpers are now treated as
though they are arrays of length 1. Previously, passing these was an error.
As a result, `numpy.ma.mr_`

now works correctly on the `masked`

constant.

`np.ptp`

accepts a `keepdims`

argument, and extended axis tuples¶

`np.ptp`

(peak-to-peak) can now work over multiple axes, just like `np.max`

and `np.min`

.

`MaskedArray.astype`

now is identical to `ndarray.astype`

¶

This means it takes all the same arguments, making more code written for ndarray work for masked array too.

#### Enable AVX2/AVX512 at compile time¶

Change to simd.inc.src to allow use of AVX2 or AVX512 at compile time. Previously compilation for avx2 (or 512) with -march=native would still use the SSE code for the simd functions even when the rest of the code got AVX2.

`nan_to_num`

always returns scalars when receiving scalar or 0d inputs¶

Previously an array was returned for integer scalar inputs, which is inconsistent with the behavior for float inputs, and that of ufuncs in general. For all types of scalar or 0d input, the result is now a scalar.

`np.flatnonzero`

works on numpy-convertible types¶

`np.flatnonzero`

now uses `np.ravel(a)`

instead of `a.ravel()`

, so it
works for lists, tuples, etc.

`np.interp`

returns numpy scalars rather than builtin scalars¶

Previously `np.interp(0.5, [0, 1], [10, 20])`

would return a `float`

, but
now it returns a `np.float64`

object, which more closely matches the behavior
of other functions.

Additionally, the special case of `np.interp(object_array_0d, ...)`

is no
longer supported, as `np.interp(object_array_nd)`

was never supported anyway.

As a result of this change, the `period`

argument can now be used on 0d
arrays.

#### Allow dtype field names to be unicode in Python 2¶

Previously `np.dtype([(u'name', float)])`

would raise a `TypeError`

in
Python 2, as only bytestrings were allowed in field names. Now any unicode
string field names will be encoded with the `ascii`

codec, raising a
`UnicodeEncodeError`

upon failure.

This change makes it easier to write Python 2/3 compatible code using
`from __future__ import unicode_literals`

, which previously would cause
string literal field names to raise a TypeError in Python 2.

#### Comparison ufuncs accept `dtype=object`

, overriding the default `bool`

¶

This allows object arrays of symbolic types, which override `==`

and other
operators to return expressions, to be compared elementwise with
`np.equal(a, b, dtype=object)`

.

`sort`

functions accept `kind='stable'`

¶

Up until now, to perform a stable sort on the data, the user must do:

```
>>> np.sort([5, 2, 6, 2, 1], kind='mergesort')
[1, 2, 2, 5, 6]
```

because merge sort is the only stable sorting algorithm available in NumPy. However, having kind=’mergesort’ does not make it explicit that the user wants to perform a stable sort thus harming the readability.

This change allows the user to specify kind=’stable’ thus clarifying the intent.

#### Do not make temporary copies for in-place accumulation¶

When ufuncs perform accumulation they no longer make temporary copies because of the overlap between input an output, that is, the next element accumulated is added before the accumulated result is stored in its place, hence the overlap is safe. Avoiding the copy results in faster execution.

`linalg.matrix_power`

can now handle stacks of matrices¶

Like other functions in `linalg`

, `matrix_power`

can now deal with arrays
of dimension larger than 2, which are treated as stacks of matrices. As part
of the change, to further improve consistency, the name of the first argument
has been changed to `a`

(from `M`

), and the exceptions for non-square
matrices have been changed to `LinAlgError`

(from `ValueError`

).

#### Increased performance in `random.permutation`

for multidimensional arrays¶

`permutation`

uses the fast path in `random.shuffle`

for all input
array dimensions. Previously the fast path was only used for 1-d arrays.

#### Generalized ufuncs now accept `axes`

, `axis`

and `keepdims`

arguments¶

One can control over which axes a generalized ufunc operates by passing in an
`axes`

argument, a list of tuples with indices of particular axes. For
instance, for a signature of `(i,j),(j,k)->(i,k)`

appropriate for matrix
multiplication, the base elements are two-dimensional matrices and these are
taken to be stored in the two last axes of each argument. The corresponding
axes keyword would be `[(-2, -1), (-2, -1), (-2, -1)]`

. If one wanted to
use leading dimensions instead, one would pass in `[(0, 1), (0, 1), (0, 1)]`

.

For simplicity, for generalized ufuncs that operate on 1-dimensional arrays
(vectors), a single integer is accepted instead of a single-element tuple, and
for generalized ufuncs for which all outputs are scalars, the (empty) output
tuples can be omitted. Hence, for a signature of `(i),(i)->()`

appropriate
for an inner product, one could pass in `axes=[0, 0]`

to indicate that the
vectors are stored in the first dimensions of the two inputs arguments.

As a short-cut for generalized ufuncs that are similar to reductions, i.e.,
that act on a single, shared core dimension such as the inner product example
above, one can pass an `axis`

argument. This is equivalent to passing in
`axes`

with identical entries for all arguments with that core dimension
(e.g., for the example above, `axes=[(axis,), (axis,)]`

).

Furthermore, like for reductions, for generalized ufuncs that have inputs that
all have the same number of core dimensions and outputs with no core dimension,
one can pass in `keepdims`

to leave a dimension with size 1 in the outputs,
thus allowing proper broadcasting against the original inputs. The location of
the extra dimension can be controlled with `axes`

. For instance, for the
inner-product example, `keepdims=True, axes=[-2, -2, -2]`

would act on the
inner-product example, `keepdims=True, axis=-2`

would act on the
one-but-last dimension of the input arguments, and leave a size 1 dimension in
that place in the output.

#### float128 values now print correctly on ppc systems¶

Previously printing float128 values was buggy on ppc, since the special double-double floating-point-format on these systems was not accounted for. float128s now print with correct rounding and uniqueness.

Warning to ppc users: You should upgrade glibc if it is version <=2.23, especially if using float128. On ppc, glibc’s malloc in these version often misaligns allocated memory which can crash numpy when using float128 values.

#### New `np.take_along_axis`

and `np.put_along_axis`

functions¶

When used on multidimensional arrays, `argsort`

, `argmin`

, `argmax`

, and
`argpartition`

return arrays that are difficult to use as indices.
`take_along_axis`

provides an easy way to use these indices to lookup values
within an array, so that:

```
np.take_along_axis(a, np.argsort(a, axis=axis), axis=axis)
```

is the same as:

```
np.sort(a, axis=axis)
```

`np.put_along_axis`

acts as the dual operation for writing to these indices
within an array.

## NumPy 1.14.6 Release Notes¶

This is a bugfix release for bugs reported following the 1.14.5 release. The most significant fixes are:

- Fix for behavior change in
`ma.masked_values(shrink=True)`

- Fix the new cached allocations machinery to be thread safe.

The Python versions supported in this release are 2.7 and 3.4 - 3.7. The Python 3.6 wheels on PyPI should be compatible with all Python 3.6 versions.

### Contributors¶

A total of 4 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Eric Wieser
- Julian Taylor
- Matti Picus

### Pull requests merged¶

A total of 4 pull requests were merged for this release.

## NumPy 1.14.5 Release Notes¶

This is a bugfix release for bugs reported following the 1.14.4 release. The most significant fixes are:

- fixes for compilation errors on alpine and NetBSD

The Python versions supported in this release are 2.7 and 3.4 - 3.6. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. The source releases were cythonized with Cython 0.28.2 and should work for the upcoming Python 3.7.

### Contributors¶

A total of 1 person contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris

## NumPy 1.14.4 Release Notes¶

This is a bugfix release for bugs reported following the 1.14.3 release. The most significant fixes are:

- fixes for compiler instruction reordering that resulted in NaN’s not being
properly propagated in
*np.max*and*np.min*, - fixes for bus faults on SPARC and older ARM due to incorrect alignment checks.

There are also improvements to printing of long doubles on PPC platforms. All is not yet perfect on that platform, the whitespace padding is still incorrect and is to be fixed in numpy 1.15, consequently NumPy still fails some printing-related (and other) unit tests on ppc systems. However, the printed values are now correct.

Note that NumPy will error on import if it detects incorrect float32 *dot*
results. This problem has been seen on the Mac when working in the Anaconda
enviroment and is due to a subtle interaction between MKL and PyQt5. It is not
strictly a NumPy problem, but it is best that users be aware of it. See the
gh-8577 NumPy issue for more information.

The Python versions supported in this release are 2.7 and 3.4 - 3.6. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. The source releases were cythonized with Cython 0.28.2 and should work for the upcoming Python 3.7.

### Contributors¶

A total of 7 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Charles Harris
- Marten van Kerkwijk
- Matti Picus
- Pauli Virtanen
- Ryan Soklaski +
- Sebastian Berg

### Pull requests merged¶

A total of 11 pull requests were merged for this release.

- #11104: BUG: str of DOUBLE_DOUBLE format wrong on ppc64
- #11170: TST: linalg: add regression test for gh-8577
- #11174: MAINT: add sanity-checks to be run at import time
- #11181: BUG: void dtype setup checked offset not actual pointer for alignment
- #11194: BUG: Python2 doubles don’t print correctly in interactive shell.
- #11198: BUG: optimizing compilers can reorder call to npy_get_floatstatus
- #11199: BUG: reduce using SSE only warns if inside SSE loop
- #11203: BUG: Bytes delimiter/comments in genfromtxt should be decoded
- #11211: BUG: Fix reference count/memory leak exposed by better testing
- #11219: BUG: Fixes einsum broadcasting bug when optimize=True
- #11251: DOC: Document 1.14.4 release.

## NumPy 1.14.3 Release Notes¶

This is a bugfix release for a few bugs reported following the 1.14.2 release:

- np.lib.recfunctions.fromrecords accepts a list-of-lists, until 1.15
- In python2, float types use the new print style when printing to a file
- style arg in “legacy” print mode now works for 0d arrays

The Python versions supported in this release are 2.7 and 3.4 - 3.6. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. The source releases were cythonized with Cython 0.28.2.

### Contributors¶

A total of 6 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Charles Harris
- Jonathan March +
- Malcolm Smith +
- Matti Picus
- Pauli Virtanen

### Pull requests merged¶

A total of 8 pull requests were merged for this release.

- #10862: BUG: floating types should override tp_print (1.14 backport)
- #10905: BUG: for 1.14 back-compat, accept list-of-lists in fromrecords
- #10947: BUG: ‘style’ arg to array2string broken in legacy mode (1.14…
- #10959: BUG: test, fix for missing flags[‘WRITEBACKIFCOPY’] key
- #10960: BUG: Add missing underscore to prototype in check_embedded_lapack
- #10961: BUG: Fix encoding regression in ma/bench.py (Issue #10868)
- #10962: BUG: core: fix NPY_TITLE_KEY macro on pypy
- #10974: BUG: test, fix PyArray_DiscardWritebackIfCopy…

## NumPy 1.14.2 Release Notes¶

This is a bugfix release for some bugs reported following the 1.14.1 release. The major problems dealt with are as follows.

- Residual bugs in the new array printing functionality.
- Regression resulting in a relocation problem with shared library.
- Improved PyPy compatibility.

The Python versions supported in this release are 2.7 and 3.4 - 3.6. The Python
3.6 wheels available from PIP are built with Python 3.6.2 and should be
compatible with all previous versions of Python 3.6. The source releases were
cythonized with Cython 0.26.1, which is known to **not** support the upcoming
Python 3.7 release. People who wish to run Python 3.7 should check out the
NumPy repo and try building with the, as yet, unreleased master branch of
Cython.

### Contributors¶

- Allan Haldane
- Charles Harris
- Eric Wieser
- Pauli Virtanen

### Pull requests merged¶

A total of 5 pull requests were merged for this release.

- #10674: BUG: Further back-compat fix for subclassed array repr
- #10725: BUG: dragon4 fractional output mode adds too many trailing zeros
- #10726: BUG: Fix f2py generated code to work on PyPy
- #10727: BUG: Fix missing NPY_VISIBILITY_HIDDEN on npy_longdouble_to_PyLong
- #10729: DOC: Create 1.14.2 notes and changelog.

## NumPy 1.14.1 Release Notes¶

This is a bugfix release for some problems reported following the 1.14.0 release. The major problems fixed are the following.

- Problems with the new array printing, particularly the printing of complex values, Please report any additional problems that may turn up.
- Problems with
`np.einsum`

due to the new`optimized=True`

default. Some fixes for optimization have been applied and`optimize=False`

is now the default. - The sort order in
`np.unique`

when`axis=<some-number>`

will now always be lexicographic in the subarray elements. In previous NumPy versions there was an optimization that could result in sorting the subarrays as unsigned byte strings. - The change in 1.14.0 that multi-field indexing of structured arrays returns a view instead of a copy has been reverted but remains on track for NumPy 1.15. Affected users should read the 1.14.1 Numpy User Guide section “basics/structured arrays/accessing multiple fields” for advice on how to manage this transition.

The Python versions supported in this release are 2.7 and 3.4 - 3.6. The Python
3.6 wheels available from PIP are built with Python 3.6.2 and should be
compatible with all previous versions of Python 3.6. The source releases were
cythonized with Cython 0.26.1, which is known to **not** support the upcoming
Python 3.7 release. People who wish to run Python 3.7 should check out the
NumPy repo and try building with the, as yet, unreleased master branch of
Cython.

### Contributors¶

A total of 14 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Charles Harris
- Daniel Smith
- Dennis Weyland +
- Eric Larson
- Eric Wieser
- Jarrod Millman
- Kenichi Maehashi +
- Marten van Kerkwijk
- Mathieu Lamarre
- Sebastian Berg
- Simon Conseil
- Simon Gibbons
- xoviat

### Pull requests merged¶

A total of 36 pull requests were merged for this release.

- #10339: BUG: restrict the __config__ modifications to win32
- #10368: MAINT: Adjust type promotion in linalg.norm
- #10375: BUG: add missing paren and remove quotes from repr of fieldless…
- #10395: MAINT: Update download URL in setup.py.
- #10396: BUG: fix einsum issue with unicode input and py2
- #10397: BUG: fix error message not formatted in einsum
- #10398: DOC: add documentation about how to handle new array printing
- #10403: BUG: Set einsum optimize parameter default to
*False*. - #10424: ENH: Fix repr of np.record objects to match np.void types #10412
- #10425: MAINT: Update zesty to artful for i386 testing
- #10431: REL: Add 1.14.1 release notes template
- #10435: MAINT: Use ValueError for duplicate field names in lookup (backport)
- #10534: BUG: Provide a better error message for out-of-order fields
- #10536: BUG: Resize bytes columns in genfromtxt (backport of #10401)
- #10537: BUG: multifield-indexing adds padding bytes: revert for 1.14.1
- #10539: BUG: fix np.save issue with python 2.7.5
- #10540: BUG: Add missing DECREF in Py2 int() cast
- #10541: TST: Add circleci document testing to maintenance/1.14.x
- #10542: BUG: complex repr has extra spaces, missing + (1.14 backport)
- #10550: BUG: Set missing exception after malloc
- #10557: BUG: In numpy.i, clear CARRAY flag if wrapped buffer is not C_CONTIGUOUS.
- #10558: DEP: Issue FutureWarning when malformed records detected.
- #10559: BUG: Fix einsum optimize logic for singleton dimensions
- #10560: BUG: Fix calling ufuncs with a positional output argument.
- #10561: BUG: Fix various Big-Endian test failures (ppc64)
- #10562: BUG: Make dtype.descr error for out-of-order fields.
- #10563: BUG: arrays not being flattened in
*union1d* - #10607: MAINT: Update sphinxext submodule hash.
- #10608: BUG: Revert sort optimization in np.unique.
- #10609: BUG: infinite recursion in str of 0d subclasses
- #10610: BUG: Align type definition with generated lapack
- #10612: BUG/ENH: Improve output for structured non-void types
- #10622: BUG: deallocate recursive closure in arrayprint.py (1.14 backport)
- #10624: BUG: Correctly identify comma separated dtype strings
- #10629: BUG: deallocate recursive closure in arrayprint.py (backport…
- #10630: REL: Prepare for 1.14.1 release.

## NumPy 1.14.0 Release Notes¶

Numpy 1.14.0 is the result of seven months of work and contains a large number of bug fixes and new features, along with several changes with potential compatibility issues. The major change that users will notice are the stylistic changes in the way numpy arrays and scalars are printed, a change that will affect doctests. See below for details on how to preserve the old style printing when needed.

A major decision affecting future development concerns the schedule for dropping Python 2.7 support in the runup to 2020. The decision has been made to support 2.7 for all releases made in 2018, with the last release being designated a long term release with support for bug fixes extending through 2019. In 2019 support for 2.7 will be dropped in all new releases. More details can be found in NEP 12.

This release supports Python 2.7 and 3.4 - 3.6.

### Highlights¶

- The
*np.einsum*function uses BLAS when possible `genfromtxt`

,`loadtxt`

,`fromregex`

and`savetxt`

can now handle files with arbitrary Python supported encoding.- Major improvements to printing of NumPy arrays and scalars.

### New functions¶

`parametrize`

: decorator added to numpy.testing`chebinterpolate`

: Interpolate function at Chebyshev points.`format_float_positional`

and`format_float_scientific`

: format floating-point scalars unambiguously with control of rounding and padding.`PyArray_ResolveWritebackIfCopy`

and`PyArray_SetWritebackIfCopyBase`

, new C-API functions useful in achieving PyPy compatibity.

### Deprecations¶

- Using
`np.bool_`

objects in place of integers is deprecated. Previously`operator.index(np.bool_)`

was legal and allowed constructs such as`[1, 2, 3][np.True_]`

. That was misleading, as it behaved differently from`np.array([1, 2, 3])[np.True_]`

. - Truth testing of an empty array is deprecated. To check if an array is not
empty, use
`array.size > 0`

. - Calling
`np.bincount`

with`minlength=None`

is deprecated.`minlength=0`

should be used instead. - Calling
`np.fromstring`

with the default value of the`sep`

argument is deprecated. When that argument is not provided, a broken version of`np.frombuffer`

is used that silently accepts unicode strings and – after encoding them as either utf-8 (python 3) or the default encoding (python 2) – treats them as binary data. If reading binary data is desired,`np.frombuffer`

should be used directly. - The
`style`

option of array2string is deprecated in non-legacy printing mode. `PyArray_SetUpdateIfCopyBase`

has been deprecated. For NumPy versions >= 1.14 use`PyArray_SetWritebackIfCopyBase`

instead, see*C API changes*below for more details.- The use of
`UPDATEIFCOPY`

arrays is deprecated, see*C API changes*below for details. We will not be dropping support for those arrays, but they are not compatible with PyPy.

### Future Changes¶

`np.issubdtype`

will stop downcasting dtype-like arguments. It might be expected that`issubdtype(np.float32, 'float64')`

and`issubdtype(np.float32, np.float64)`

mean the same thing - however, there was an undocumented special case that translated the former into`issubdtype(np.float32, np.floating)`

, giving the surprising result of True.This translation now gives a warning that explains what translation is occurring. In the future, the translation will be disabled, and the first example will be made equivalent to the second.

`np.linalg.lstsq`

default for`rcond`

will be changed. The`rcond`

parameter to`np.linalg.lstsq`

will change its default to machine precision times the largest of the input array dimensions. A FutureWarning is issued when`rcond`

is not passed explicitly.`a.flat.__array__()`

will return a writeable copy of`a`

when`a`

is non-contiguous. Previously it returned an UPDATEIFCOPY array when`a`

was writeable. Currently it returns a non-writeable copy. See gh-7054 for a discussion of the issue.Unstructured void array’s

`.item`

method will return a bytes object. In the future, calling`.item()`

on arrays or scalars of`np.void`

datatype will return a`bytes`

object instead of a buffer or int array, the same as returned by`bytes(void_scalar)`

. This may affect code which assumed the return value was mutable, which will no longer be the case. A`FutureWarning`

is now issued when this would occur.

### Compatibility notes¶

#### The mask of a masked array view is also a view rather than a copy¶

There was a FutureWarning about this change in NumPy 1.11.x. In short, it is
now the case that, when changing a view of a masked array, changes to the mask
are propagated to the original. That was not previously the case. This change
affects slices in particular. Note that this does not yet work properly if the
mask of the original array is `nomask`

and the mask of the view is changed.
See gh-5580 for an extended discussion. The original behavior of having a copy
of the mask can be obtained by calling the `unshare_mask`

method of the view.

`np.ma.masked`

is no longer writeable¶

Attempts to mutate the `masked`

constant now error, as the underlying arrays
are marked readonly. In the past, it was possible to get away with:

```
# emulating a function that sometimes returns np.ma.masked
val = random.choice([np.ma.masked, 10])
var_arr = np.asarray(val)
val_arr += 1 # now errors, previously changed np.ma.masked.data
```

`np.ma`

functions producing `fill_value`

s have changed¶

Previously, `np.ma.default_fill_value`

would return a 0d array, but
`np.ma.minimum_fill_value`

and `np.ma.maximum_fill_value`

would return a
tuple of the fields. Instead, all three methods return a structured `np.void`

object, which is what you would already find in the `.fill_value`

attribute.

Additionally, the dtype guessing now matches that of `np.array`

- so when
passing a python scalar `x`

, `maximum_fill_value(x)`

is always the same as
`maximum_fill_value(np.array(x))`

. Previously `x = long(1)`

on Python 2
violated this assumption.

`a.flat.__array__()`

returns non-writeable arrays when `a`

is non-contiguous¶

The intent is that the UPDATEIFCOPY array previously returned when `a`

was
non-contiguous will be replaced by a writeable copy in the future. This
temporary measure is aimed to notify folks who expect the underlying array be
modified in this situation that that will no longer be the case. The most
likely places for this to be noticed is when expressions of the form
`np.asarray(a.flat)`

are used, or when `a.flat`

is passed as the out
parameter to a ufunc.

`np.tensordot`

now returns zero array when contracting over 0-length dimension¶

Previously `np.tensordot`

raised a ValueError when contracting over 0-length
dimension. Now it returns a zero array, which is consistent with the behaviour
of `np.dot`

and `np.einsum`

.

`numpy.testing`

reorganized¶

This is not expected to cause problems, but possibly something has been left
out. If you experience an unexpected import problem using `numpy.testing`

let us know.

`np.asfarray`

no longer accepts non-dtypes through the `dtype`

argument¶

This previously would accept `dtype=some_array`

, with the implied semantics
of `dtype=some_array.dtype`

. This was undocumented, unique across the numpy
functions, and if used would likely correspond to a typo.

#### 1D `np.linalg.norm`

preserves float input types, even for arbitrary orders¶

Previously, this would promote to `float64`

when arbitrary orders were
passed, despite not doing so under the simple cases:

```
>>> f32 = np.float32([[1, 2]])
>>> np.linalg.norm(f32, 2.0, axis=-1).dtype
dtype('float32')
>>> np.linalg.norm(f32, 2.0001, axis=-1).dtype
dtype('float64') # numpy 1.13
dtype('float32') # numpy 1.14
```

This change affects only `float32`

and `float16`

arrays.

`count_nonzero(arr, axis=())`

now counts over no axes, not all axes¶

Elsewhere, `axis==()`

is always understood as “no axes”, but
*count_nonzero* had a special case to treat this as “all axes”. This was
inconsistent and surprising. The correct way to count over all axes has always
been to pass `axis == None`

.

`__init__.py`

files added to test directories¶

This is for pytest compatibility in the case of duplicate test file names in
the different directories. As a result, `run_module_suite`

no longer works,
i.e., `python <path-to-test-file>`

results in an error.

`.astype(bool)`

on unstructured void arrays now calls `bool`

on each element¶

On Python 2, `void_array.astype(bool)`

would always return an array of
`True`

, unless the dtype is `V0`

. On Python 3, this operation would usually
crash. Going forwards, *astype* matches the behavior of `bool(np.void)`

,
considering a buffer of all zeros as false, and anything else as true.
Checks for `V0`

can still be done with `arr.dtype.itemsize == 0`

.

`MaskedArray.squeeze`

never returns `np.ma.masked`

¶

`np.squeeze`

is documented as returning a view, but the masked variant would
sometimes return `masked`

, which is not a view. This has been fixed, so that
the result is always a view on the original masked array.
This breaks any code that used `masked_arr.squeeze() is np.ma.masked`

, but
fixes code that writes to the result of *squeeze()*.

#### Renamed first parameter of `can_cast`

from `from`

to `from_`

¶

The previous parameter name `from`

is a reserved keyword in Python, which made
it difficult to pass the argument by name. This has been fixed by renaming
the parameter to `from_`

.

`isnat`

raises `TypeError`

when passed wrong type¶

The ufunc `isnat`

used to raise a `ValueError`

when it was not passed
variables of type `datetime`

or `timedelta`

. This has been changed to
raising a `TypeError`

.

`dtype.__getitem__`

raises `TypeError`

when passed wrong type¶

When indexed with a float, the dtype object used to raise `ValueError`

.

#### User-defined types now need to implement `__str__`

and `__repr__`

¶

Previously, user-defined types could fall back to a default implementation of
`__str__`

and `__repr__`

implemented in numpy, but this has now been
removed. Now user-defined types will fall back to the python default
`object.__str__`

and `object.__repr__`

.

#### Many changes to array printing, disableable with the new “legacy” printing mode¶

The `str`

and `repr`

of ndarrays and numpy scalars have been changed in
a variety of ways. These changes are likely to break downstream user’s
doctests.

These new behaviors can be disabled to mostly reproduce numpy 1.13 behavior by
enabling the new 1.13 “legacy” printing mode. This is enabled by calling
`np.set_printoptions(legacy="1.13")`

, or using the new `legacy`

argument to
`np.array2string`

, as `np.array2string(arr, legacy='1.13')`

.

In summary, the major changes are:

- For floating-point types:
- The
`repr`

of float arrays often omits a space previously printed in the sign position. See the new`sign`

option to`np.set_printoptions`

. - Floating-point arrays and scalars use a new algorithm for decimal
representations, giving the shortest unique representation. This will
usually shorten
`float16`

fractional output, and sometimes`float32`

and`float128`

output.`float64`

should be unaffected. See the new`floatmode`

option to`np.set_printoptions`

. - Float arrays printed in scientific notation no longer use fixed-precision, and now instead show the shortest unique representation.
- The
`str`

of floating-point scalars is no longer truncated in python2.

- The
- For other data types:
- Non-finite complex scalars print like
`nanj`

instead of`nan*j`

. `NaT`

values in datetime arrays are now properly aligned.- Arrays and scalars of
`np.void`

datatype are now printed using hex notation.

- Non-finite complex scalars print like
- For line-wrapping:
- The “dtype” part of ndarray reprs will now be printed on the next line if there isn’t space on the last line of array output.
- The
`linewidth`

format option is now always respected. The*repr*or*str*of an array will never exceed this, unless a single element is too wide. - The last line of an array string will never have more elements than earlier lines.
- An extra space is no longer inserted on the first line if the elements are too wide.

- For summarization (the use of
`...`

to shorten long arrays):- A trailing comma is no longer inserted for
`str`

. Previously,`str(np.arange(1001))`

gave`'[ 0 1 2 ..., 998 999 1000]'`

, which has an extra comma. - For arrays of 2-D and beyond, when
`...`

is printed on its own line in order to summarize any but the last axis, newlines are now appended to that line to match its leading newlines and a trailing space character is removed.

- A trailing comma is no longer inserted for
`MaskedArray`

arrays now separate printed elements with commas, always print the dtype, and correctly wrap the elements of long arrays to multiple lines. If there is more than 1 dimension, the array attributes are now printed in a new “left-justified” printing style.`recarray`

arrays no longer print a trailing space before their dtype, and wrap to the right number of columns.- 0d arrays no longer have their own idiosyncratic implementations of
`str`

and`repr`

. The`style`

argument to`np.array2string`

is deprecated. - Arrays of
`bool`

datatype will omit the datatype in the`repr`

. - User-defined
`dtypes`

(subclasses of`np.generic`

) now need to implement`__str__`

and`__repr__`

.

Some of these changes are described in more detail below. If you need to retain the previous behavior for doctests or other reasons, you may want to do something like:

```
# FIXME: We need the str/repr formatting used in Numpy < 1.14.
try:
np.set_printoptions(legacy='1.13')
except TypeError:
pass
```

### C API changes¶

#### PyPy compatible alternative to `UPDATEIFCOPY`

arrays¶

`UPDATEIFCOPY`

arrays are contiguous copies of existing arrays, possibly with
different dimensions, whose contents are copied back to the original array when
their refcount goes to zero and they are deallocated. Because PyPy does not use
refcounts, they do not function correctly with PyPy. NumPy is in the process of
eliminating their use internally and two new C-API functions,

`PyArray_SetWritebackIfCopyBase`

`PyArray_ResolveWritebackIfCopy`

,

have been added together with a complimentary flag,
`NPY_ARRAY_WRITEBACKIFCOPY`

. Using the new functionality also requires that
some flags be changed when new arrays are created, to wit:
`NPY_ARRAY_INOUT_ARRAY`

should be replaced by `NPY_ARRAY_INOUT_ARRAY2`

and
`NPY_ARRAY_INOUT_FARRAY`

should be replaced by `NPY_ARRAY_INOUT_FARRAY2`

.
Arrays created with these new flags will then have the `WRITEBACKIFCOPY`

semantics.

If PyPy compatibility is not a concern, these new functions can be ignored,
although there will be a `DeprecationWarning`

. If you do wish to pursue PyPy
compatibility, more information on these functions and their use may be found
in the c-api documentation and the example in how-to-extend.

### New Features¶

#### Encoding argument for text IO functions¶

`genfromtxt`

, `loadtxt`

, `fromregex`

and `savetxt`

can now handle files
with arbitrary encoding supported by Python via the encoding argument.
For backward compatibility the argument defaults to the special `bytes`

value
which continues to treat text as raw byte values and continues to pass latin1
encoded bytes to custom converters.
Using any other value (including `None`

for system default) will switch the
functions to real text IO so one receives unicode strings instead of bytes in
the resulting arrays.

#### External `nose`

plugins are usable by `numpy.testing.Tester`

¶

`numpy.testing.Tester`

is now aware of `nose`

plugins that are outside the
`nose`

built-in ones. This allows using, for example, `nose-timer`

like
so: `np.test(extra_argv=['--with-timer', '--timer-top-n', '20'])`

to
obtain the runtime of the 20 slowest tests. An extra keyword `timer`

was
also added to `Tester.test`

, so `np.test(timer=20)`

will also report the 20
slowest tests.

`parametrize`

decorator added to `numpy.testing`

¶

A basic `parametrize`

decorator is now available in `numpy.testing`

. It is
intended to allow rewriting yield based tests that have been deprecated in
pytest so as to facilitate the transition to pytest in the future. The nose
testing framework has not been supported for several years and looks like
abandonware.

The new `parametrize`

decorator does not have the full functionality of the
one in pytest. It doesn’t work for classes, doesn’t support nesting, and does
not substitute variable names. Even so, it should be adequate to rewrite the
NumPy tests.

`chebinterpolate`

function added to `numpy.polynomial.chebyshev`

¶

The new `chebinterpolate`

function interpolates a given function at the
Chebyshev points of the first kind. A new `Chebyshev.interpolate`

class
method adds support for interpolation over arbitrary intervals using the scaled
and shifted Chebyshev points of the first kind.

#### Support for reading lzma compressed text files in Python 3¶

With Python versions containing the `lzma`

module the text IO functions can
now transparently read from files with `xz`

or `lzma`

extension.

`sign`

option added to `np.setprintoptions`

and `np.array2string`

¶

This option controls printing of the sign of floating-point types, and may be one of the characters ‘-‘, ‘+’ or ‘ ‘. With ‘+’ numpy always prints the sign of positive values, with ‘ ‘ it always prints a space (whitespace character) in the sign position of positive values, and with ‘-‘ it will omit the sign character for positive values. The new default is ‘-‘.

This new default changes the float output relative to numpy 1.13. The old behavior can be obtained in 1.13 “legacy” printing mode, see compatibility notes above.

`hermitian`

option added to``np.linalg.matrix_rank``¶

The new `hermitian`

option allows choosing between standard SVD based matrix
rank calculation and the more efficient eigenvalue based method for
symmetric/hermitian matrices.

`threshold`

and `edgeitems`

options added to `np.array2string`

¶

These options could previously be controlled using `np.set_printoptions`

, but
now can be changed on a per-call basis as arguments to `np.array2string`

.

`concatenate`

and `stack`

gained an `out`

argument¶

A preallocated buffer of the desired dtype can now be used for the output of these functions.

#### Support for PGI flang compiler on Windows¶

The PGI flang compiler is a Fortran front end for LLVM released by NVIDIA under the Apache 2 license. It can be invoked by

```
python setup.py config --compiler=clang --fcompiler=flang install
```

There is little experience with this new compiler, so any feedback from people using it will be appreciated.

### Improvements¶

#### Numerator degrees of freedom in `random.noncentral_f`

need only be positive.¶

Prior to NumPy 1.14.0, the numerator degrees of freedom needed to be > 1, but the distribution is valid for values > 0, which is the new requirement.

#### The GIL is released for all `np.einsum`

variations¶

Some specific loop structures which have an accelerated loop version did not release the GIL prior to NumPy 1.14.0. This oversight has been fixed.

#### The *np.einsum* function will use BLAS when possible and optimize by default¶

The `np.einsum`

function will now call `np.tensordot`

when appropriate.
Because `np.tensordot`

uses BLAS when possible, that will speed up execution.
By default, `np.einsum`

will also attempt optimization as the overhead is
small relative to the potential improvement in speed.

`f2py`

now handles arrays of dimension 0¶

`f2py`

now allows for the allocation of arrays of dimension 0. This allows
for more consistent handling of corner cases downstream.

`numpy.distutils`

supports using MSVC and mingw64-gfortran together¶

Numpy distutils now supports using Mingw64 gfortran and MSVC compilers together. This enables the production of Python extension modules on Windows containing Fortran code while retaining compatibility with the binaries distributed by Python.org. Not all use cases are supported, but most common ways to wrap Fortran for Python are functional.

Compilation in this mode is usually enabled automatically, and can be
selected via the `--fcompiler`

and `--compiler`

options to
`setup.py`

. Moreover, linking Fortran codes to static OpenBLAS is
supported; by default a gfortran compatible static archive
`openblas.a`

is looked for.

`np.linalg.pinv`

now works on stacked matrices¶

Previously it was limited to a single 2d array.

`numpy.save`

aligns data to 64 bytes instead of 16¶

Saving NumPy arrays in the `npy`

format with `numpy.save`

inserts
padding before the array data to align it at 64 bytes. Previously
this was only 16 bytes (and sometimes less due to a bug in the code
for version 2). Now the alignment is 64 bytes, which matches the
widest SIMD instruction set commonly available, and is also the most
common cache line size. This makes `npy`

files easier to use in
programs which open them with `mmap`

, especially on Linux where an
`mmap`

offset must be a multiple of the page size.

#### NPZ files now can be written without using temporary files¶

In Python 3.6+ `numpy.savez`

and `numpy.savez_compressed`

now write
directly to a ZIP file, without creating intermediate temporary files.

#### Better support for empty structured and string types¶

Structured types can contain zero fields, and string dtypes can contain zero characters. Zero-length strings still cannot be created directly, and must be constructed through structured dtypes:

```
str0 = np.empty(10, np.dtype([('v', str, N)]))['v']
void0 = np.empty(10, np.void)
```

It was always possible to work with these, but the following operations are now supported for these arrays:

arr.sort()arr.view(bytes)arr.resize(…)pickle.dumps(arr)

#### Support for `decimal.Decimal`

in `np.lib.financial`

¶

Unless otherwise stated all functions within the `financial`

package now
support using the `decimal.Decimal`

built-in type.

#### Float printing now uses “dragon4” algorithm for shortest decimal representation¶

The `str`

and `repr`

of floating-point values (16, 32, 64 and 128 bit) are
now printed to give the shortest decimal representation which uniquely
identifies the value from others of the same type. Previously this was only
true for `float64`

values. The remaining float types will now often be shorter
than in numpy 1.13. Arrays printed in scientific notation now also use the
shortest scientific representation, instead of fixed precision as before.

Additionally, thestrof float scalars scalars will no longer be truncated in python2, unlike python2float`s. `np.doublescalars now have a`str`

and`repr`

identical to that of a python3 float.

New functions `np.format_float_scientific`

and `np.format_float_positional`

are provided to generate these decimal representations.

A new option `floatmode`

has been added to `np.set_printoptions`

and
`np.array2string`

, which gives control over uniqueness and rounding of
printed elements in an array. The new default is `floatmode='maxprec'`

with
`precision=8`

, which will print at most 8 fractional digits, or fewer if an
element can be uniquely represented with fewer. A useful new mode is
`floatmode="unique"`

, which will output enough digits to specify the array
elements uniquely.

Numpy complex-floating-scalars with values like `inf*j`

or `nan*j`

now
print as `infj`

and `nanj`

, like the pure-python `complex`

type.

The `FloatFormat`

and `LongFloatFormat`

classes are deprecated and should
both be replaced by `FloatingFormat`

. Similarly `ComplexFormat`

and
`LongComplexFormat`

should be replaced by `ComplexFloatingFormat`

.

`void`

datatype elements are now printed in hex notation¶

A hex representation compatible with the python `bytes`

type is now printed
for unstructured `np.void`

elements, e.g., `V4`

datatype. Previously, in
python2 the raw void data of the element was printed to stdout, or in python3
the integer byte values were shown.

#### printing style for `void`

datatypes is now independently customizable¶

The printing style of `np.void`

arrays is now independently customizable
using the `formatter`

argument to `np.set_printoptions`

, using the
`'void'`

key, instead of the catch-all `numpystr`

key as before.

#### Reduced memory usage of `np.loadtxt`

¶

`np.loadtxt`

now reads files in chunks instead of all at once which decreases
its memory usage significantly for large files.

### Changes¶

#### Multiple-field indexing/assignment of structured arrays¶

The indexing and assignment of structured arrays with multiple fields has changed in a number of ways, as warned about in previous releases.

First, indexing a structured array with multiple fields, e.g.,
`arr[['f1', 'f3']]`

, returns a view into the original array instead of a
copy. The returned view will have extra padding bytes corresponding to
intervening fields in the original array, unlike the copy in 1.13, which will
affect code such as `arr[['f1', 'f3']].view(newdtype)`

.

Second, assignment between structured arrays will now occur “by position” instead of “by field name”. The Nth field of the destination will be set to the Nth field of the source regardless of field name, unlike in numpy versions 1.6 to 1.13 in which fields in the destination array were set to the identically-named field in the source array or to 0 if the source did not have a field.

Correspondingly, the order of fields in a structured dtypes now matters when computing dtype equality. For example, with the dtypes

```
x = dtype({'names': ['A', 'B'], 'formats': ['i4', 'f4'], 'offsets': [0, 4]})
y = dtype({'names': ['B', 'A'], 'formats': ['f4', 'i4'], 'offsets': [4, 0]})
```

the expression `x == y`

will now return `False`

, unlike before.
This makes dictionary based dtype specifications like
`dtype({'a': ('i4', 0), 'b': ('f4', 4)})`

dangerous in python < 3.6
since dict key order is not preserved in those versions.

Assignment from a structured array to a boolean array now raises a ValueError,
unlike in 1.13, where it always set the destination elements to `True`

.

Assignment from structured array with more than one field to a non-structured array now raises a ValueError. In 1.13 this copied just the first field of the source to the destination.

Using field “titles” in multiple-field indexing is now disallowed, as is repeating a field name in a multiple-field index.

The documentation for structured arrays in the user guide has been significantly updated to reflect these changes.

#### Integer and Void scalars are now unaffected by `np.set_string_function`

¶

Previously, unlike most other numpy scalars, the `str`

and `repr`

of
integer and void scalars could be controlled by `np.set_string_function`

.
This is no longer possible.

#### 0d array printing changed, `style`

arg of array2string deprecated¶

Previously the `str`

and `repr`

of 0d arrays had idiosyncratic
implementations which returned `str(a.item())`

and ```
'array(' +
repr(a.item()) + ')'
```

respectively for 0d array `a`

, unlike both numpy
scalars and higher dimension ndarrays.

Now, the `str`

of a 0d array acts like a numpy scalar using `str(a[()])`

and the `repr`

acts like higher dimension arrays using `formatter(a[()])`

,
where `formatter`

can be specified using `np.set_printoptions`

. The
`style`

argument of `np.array2string`

is deprecated.

This new behavior is disabled in 1.13 legacy printing mode, see compatibility notes above.

#### Seeding `RandomState`

using an array requires a 1-d array¶

`RandomState`

previously would accept empty arrays or arrays with 2 or more
dimensions, which resulted in either a failure to seed (empty arrays) or for
some of the passed values to be ignored when setting the seed.

`MaskedArray`

objects show a more useful `repr`

¶

The `repr`

of a `MaskedArray`

is now closer to the python code that would
produce it, with arrays now being shown with commas and dtypes. Like the other
formatting changes, this can be disabled with the 1.13 legacy printing mode in
order to help transition doctests.

#### The `repr`

of `np.polynomial`

classes is more explicit¶

It now shows the domain and window parameters as keyword arguments to make them more clear:

```
>>> np.polynomial.Polynomial(range(4))
Polynomial([0., 1., 2., 3.], domain=[-1, 1], window=[-1, 1])
```

## NumPy 1.13.3 Release Notes¶

This is a bugfix release for some problems found since 1.13.1. The most important fixes are for CVE-2017-12852 and temporary elision. Users of earlier versions of 1.13 should upgrade.

The Python versions supported are 2.7 and 3.4 - 3.6. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. It was cythonized with Cython 0.26.1, which should be free of the bugs found in 0.27 while also being compatible with Python 3.7-dev. The Windows wheels were built with OpenBlas instead ATLAS, which should improve the performance of the linear algebra functions.

The NumPy 1.13.3 release is a re-release of 1.13.2, which suffered from a bug in Cython 0.27.0.

### Contributors¶

A total of 12 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Brandon Carter
- Charles Harris
- Eric Wieser
- Iryna Shcherbina +
- James Bourbeau +
- Jonathan Helmus
- Julian Taylor
- Matti Picus
- Michael Lamparski +
- Michael Seifert
- Ralf Gommers

### Pull requests merged¶

A total of 22 pull requests were merged for this release.

- #9390 BUG: Return the poly1d coefficients array directly
- #9555 BUG: Fix regression in 1.13.x in distutils.mingw32ccompiler.
- #9556 BUG: Fix true_divide when dtype=np.float64 specified.
- #9557 DOC: Fix some rst markup in numpy/doc/basics.py.
- #9558 BLD: Remove -xhost flag from IntelFCompiler.
- #9559 DOC: Removes broken docstring example (source code, png, pdf)…
- #9580 BUG: Add hypot and cabs functions to WIN32 blacklist.
- #9732 BUG: Make scalar function elision check if temp is writeable.
- #9736 BUG: Various fixes to np.gradient
- #9742 BUG: Fix np.pad for CVE-2017-12852
- #9744 BUG: Check for exception in sort functions, add tests
- #9745 DOC: Add whitespace after “versionadded::” directive so it actually…
- #9746 BUG: Memory leak in np.dot of size 0
- #9747 BUG: Adjust gfortran version search regex
- #9757 BUG: Cython 0.27 breaks NumPy on Python 3.
- #9764 BUG: Ensure
*_npy_scaled_cexp{,f,l}*is defined when needed. - #9765 BUG: PyArray_CountNonzero does not check for exceptions
- #9766 BUG: Fixes histogram monotonicity check for unsigned bin values
- #9767 BUG: Ensure consistent result dtype of count_nonzero
- #9771 BUG: MAINT: Fix mtrand for Cython 0.27.
- #9772 DOC: Create the 1.13.2 release notes.
- #9794 DOC: Create 1.13.3 release notes.

## NumPy 1.13.2 Release Notes¶

This is a bugfix release for some problems found since 1.13.1. The most important fixes are for CVE-2017-12852 and temporary elision. Users of earlier versions of 1.13 should upgrade.

The Python versions supported are 2.7 and 3.4 - 3.6. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. The Windows wheels are now built with OpenBlas instead ATLAS, which should improve the performance of the linear algebra functions.

### Contributors¶

A total of 12 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Allan Haldane
- Brandon Carter
- Charles Harris
- Eric Wieser
- Iryna Shcherbina +
- James Bourbeau +
- Jonathan Helmus
- Julian Taylor
- Matti Picus
- Michael Lamparski +
- Michael Seifert
- Ralf Gommers

### Pull requests merged¶

A total of 20 pull requests were merged for this release.

- #9390 BUG: Return the poly1d coefficients array directly
- #9555 BUG: Fix regression in 1.13.x in distutils.mingw32ccompiler.
- #9556 BUG: Fix true_divide when dtype=np.float64 specified.
- #9557 DOC: Fix some rst markup in numpy/doc/basics.py.
- #9558 BLD: Remove -xhost flag from IntelFCompiler.
- #9559 DOC: Removes broken docstring example (source code, png, pdf)…
- #9580 BUG: Add hypot and cabs functions to WIN32 blacklist.
- #9732 BUG: Make scalar function elision check if temp is writeable.
- #9736 BUG: Various fixes to np.gradient
- #9742 BUG: Fix np.pad for CVE-2017-12852
- #9744 BUG: Check for exception in sort functions, add tests
- #9745 DOC: Add whitespace after “versionadded::” directive so it actually…
- #9746 BUG: Memory leak in np.dot of size 0
- #9747 BUG: Adjust gfortran version search regex
- #9757 BUG: Cython 0.27 breaks NumPy on Python 3.
- #9764 BUG: Ensure
*_npy_scaled_cexp{,f,l}*is defined when needed. - #9765 BUG: PyArray_CountNonzero does not check for exceptions
- #9766 BUG: Fixes histogram monotonicity check for unsigned bin values
- #9767 BUG: Ensure consistent result dtype of count_nonzero
- #9771 BUG, MAINT: Fix mtrand for Cython 0.27.

## NumPy 1.13.1 Release Notes¶

This is a bugfix release for problems found in 1.13.0. The major changes are
fixes for the new memory overlap detection and temporary elision as well as
reversion of the removal of the boolean binary `-`

operator. Users of 1.13.0
should upgrade.

Thr Python versions supported are 2.7 and 3.4 - 3.6. Note that the Python 3.6 wheels available from PIP are built against 3.6.1, hence will not work when used with 3.6.0 due to Python bug 29943. NumPy 1.13.2 will be released shortly after Python 3.6.2 is out to fix that problem. If you are using 3.6.0 the workaround is to upgrade to 3.6.1 or use an earlier Python version.

### Pull requests merged¶

A total of 19 pull requests were merged for this release.

- #9240 DOC: BLD: fix lots of Sphinx warnings/errors.
- #9255 Revert “DEP: Raise TypeError for subtract(bool, bool).”
- #9261 BUG: don’t elide into readonly and updateifcopy temporaries for…
- #9262 BUG: fix missing keyword rename for common block in numpy.f2py
- #9263 BUG: handle resize of 0d array
- #9267 DOC: update f2py front page and some doc build metadata.
- #9299 BUG: Fix Intel compilation on Unix.
- #9317 BUG: fix wrong ndim used in empty where check
- #9319 BUG: Make extensions compilable with MinGW on Py2.7
- #9339 BUG: Prevent crash if ufunc doc string is null
- #9340 BUG: umath: un-break ufunc where= when no out= is given
- #9371 DOC: Add isnat/positive ufunc to documentation
- #9372 BUG: Fix error in fromstring function from numpy.core.records…
- #9373 BUG: ‘)’ is printed at the end pointer of the buffer in numpy.f2py.
- #9374 DOC: Create NumPy 1.13.1 release notes.
- #9376 BUG: Prevent hang traversing ufunc userloop linked list
- #9377 DOC: Use x1 and x2 in the heaviside docstring.
- #9378 DOC: Add $PARAMS to the isnat docstring
- #9379 DOC: Update the 1.13.1 release notes

### Contributors¶

A total of 12 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Andras Deak +
- Bob Eldering +
- Charles Harris
- Daniel Hrisca +
- Eric Wieser
- Joshua Leahy +
- Julian Taylor
- Michael Seifert
- Pauli Virtanen
- Ralf Gommers
- Roland Kaufmann
- Warren Weckesser

## NumPy 1.13.0 Release Notes¶

This release supports Python 2.7 and 3.4 - 3.6.

### Highlights¶

- Operations like
`a + b + c`

will reuse temporaries on some platforms, resulting in less memory use and faster execution.- Inplace operations check if inputs overlap outputs and create temporaries to avoid problems.
- New
`__array_ufunc__`

attribute provides improved ability for classes to override default ufunc behavior.- New
`np.block`

function for creating blocked arrays.

### New functions¶

- New
`np.positive`

ufunc. - New
`np.divmod`

ufunc provides more efficient divmod. - New
`np.isnat`

ufunc tests for NaT special values. - New
`np.heaviside`

ufunc computes the Heaviside function. - New
`np.isin`

function, improves on`in1d`

. - New
`np.block`

function for creating blocked arrays. - New
`PyArray_MapIterArrayCopyIfOverlap`

added to NumPy C-API.

See below for details.

### Deprecations¶

- Calling
`np.fix`

,`np.isposinf`

, and`np.isneginf`

with`f(x, y=out)`

is deprecated - the argument should be passed as`f(x, out=out)`

, which matches other ufunc-like interfaces. - Use of the C-API
`NPY_CHAR`

type number deprecated since version 1.7 will now raise deprecation warnings at runtime. Extensions built with older f2py versions need to be recompiled to remove the warning. `np.ma.argsort`

,`np.ma.minimum.reduce`

, and`np.ma.maximum.reduce`

should be called with an explicit*axis*argument when applied to arrays with more than 2 dimensions, as the default value of this argument (`None`

) is inconsistent with the rest of numpy (`-1`

,`0`

, and`0`

, respectively).`np.ma.MaskedArray.mini`

is deprecated, as it almost duplicates the functionality of`np.MaskedArray.min`

. Exactly equivalent behaviour can be obtained with`np.ma.minimum.reduce`

.- The single-argument form of
`np.ma.minimum`

and`np.ma.maximum`

is deprecated.`np.maximum`

.`np.ma.minimum(x)`

should now be spelt`np.ma.minimum.reduce(x)`

, which is consistent with how this would be done with`np.minimum`

. - Calling
`ndarray.conjugate`

on non-numeric dtypes is deprecated (it should match the behavior of`np.conjugate`

, which throws an error). - Calling
`expand_dims`

when the`axis`

keyword does not satisfy`-a.ndim - 1 <= axis <= a.ndim`

, where`a`

is the array being reshaped, is deprecated.

### Future Changes¶

- Assignment between structured arrays with different field names will change
in NumPy 1.14. Previously, fields in the dst would be set to the value of the
identically-named field in the src. In numpy 1.14 fields will instead be
assigned ‘by position’: The n-th field of the dst will be set to the n-th
field of the src array. Note that the
`FutureWarning`

raised in NumPy 1.12 incorrectly reported this change as scheduled for NumPy 1.13 rather than NumPy 1.14.

### Build System Changes¶

`numpy.distutils`

now automatically determines C-file dependencies with GCC compatible compilers.

### Compatibility notes¶

#### Error type changes¶

`numpy.hstack()`

now throws`ValueError`

instead of`IndexError`

when input is empty.- Functions taking an axis argument, when that argument is out of range, now
throw
`np.AxisError`

instead of a mixture of`IndexError`

and`ValueError`

. For backwards compatibility,`AxisError`

subclasses both of these.

#### Tuple object dtypes¶

Support has been removed for certain obscure dtypes that were unintentionally
allowed, of the form `(old_dtype, new_dtype)`

, where either of the dtypes
is or contains the `object`

dtype. As an exception, dtypes of the form
`(object, [('name', object)])`

are still supported due to evidence of
existing use.

#### DeprecationWarning to error¶

See Changes section for more detail.

`partition`

, TypeError when non-integer partition index is used.`NpyIter_AdvancedNew`

, ValueError when`oa_ndim == 0`

and`op_axes`

is NULL`negative(bool_)`

, TypeError when negative applied to booleans.`subtract(bool_, bool_)`

, TypeError when subtracting boolean from boolean.`np.equal, np.not_equal`

, object identity doesn’t override failed comparison.`np.equal, np.not_equal`

, object identity doesn’t override non-boolean comparison.- Deprecated boolean indexing behavior dropped. See Changes below for details.
- Deprecated
`np.alterdot()`

and`np.restoredot()`

removed.

#### FutureWarning to changed behavior¶

See Changes section for more detail.

`numpy.average`

preserves subclasses`array == None`

and`array != None`

do element-wise comparison.`np.equal, np.not_equal`

, object identity doesn’t override comparison result.

#### dtypes are now always true¶

Previously `bool(dtype)`

would fall back to the default python
implementation, which checked if `len(dtype) > 0`

. Since `dtype`

objects
implement `__len__`

as the number of record fields, `bool`

of scalar dtypes
would evaluate to `False`

, which was unintuitive. Now `bool(dtype) == True`

for all dtypes.

`__getslice__`

and `__setslice__`

are no longer needed in `ndarray`

subclasses¶

When subclassing np.ndarray in Python 2.7, it is no longer _necessary_ to
implement `__*slice__`

on the derived class, as `__*item__`

will intercept
these calls correctly.

Any code that did implement these will work exactly as before. Code that
invokes``ndarray.__getslice__`` (e.g. through `super(...).__getslice__`

) will
now issue a DeprecationWarning - `.__getitem__(slice(start, end))`

should be
used instead.

#### Indexing MaskedArrays/Constants with `...`

(ellipsis) now returns MaskedArray¶

This behavior mirrors that of np.ndarray, and accounts for nested arrays in MaskedArrays of object dtype, and ellipsis combined with other forms of indexing.

### C API changes¶

#### GUfuncs on empty arrays and NpyIter axis removal¶

It is now allowed to remove a zero-sized axis from NpyIter. Which may mean that code removing axes from NpyIter has to add an additional check when accessing the removed dimensions later on.

The largest followup change is that gufuncs are now allowed to have zero-sized inner dimensions. This means that a gufunc now has to anticipate an empty inner dimension, while this was never possible and an error raised instead.

For most gufuncs no change should be necessary. However, it is now possible
for gufuncs with a signature such as `(..., N, M) -> (..., M)`

to return
a valid result if `N=0`

without further wrapping code.

`PyArray_MapIterArrayCopyIfOverlap`

added to NumPy C-API¶

Similar to `PyArray_MapIterArray`

but with an additional `copy_if_overlap`

argument. If `copy_if_overlap != 0`

, checks if input has memory overlap with
any of the other arrays and make copies as appropriate to avoid problems if the
input is modified during the iteration. See the documentation for more complete
documentation.

### New Features¶

`__array_ufunc__`

added¶

This is the renamed and redesigned `__numpy_ufunc__`

. Any class, ndarray
subclass or not, can define this method or set it to `None`

in order to
override the behavior of NumPy’s ufuncs. This works quite similarly to Python’s
`__mul__`

and other binary operation routines. See the documentation for a
more detailed description of the implementation and behavior of this new
option. The API is provisional, we do not yet guarantee backward compatibility
as modifications may be made pending feedback. See NEP 13 and
documentation for more details.

#### New `positive`

ufunc¶

This ufunc corresponds to unary *+*, but unlike *+* on an ndarray it will raise
an error if array values do not support numeric operations.

#### New `divmod`

ufunc¶

This ufunc corresponds to the Python builtin *divmod*, and is used to implement
*divmod* when called on numpy arrays. `np.divmod(x, y)`

calculates a result
equivalent to `(np.floor_divide(x, y), np.remainder(x, y))`

but is
approximately twice as fast as calling the functions separately.

`np.isnat`

ufunc tests for NaT special datetime and timedelta values¶

The new ufunc `np.isnat`

finds the positions of special NaT values
within datetime and timedelta arrays. This is analogous to `np.isnan`

.

`np.heaviside`

ufunc computes the Heaviside function¶

The new function `np.heaviside(x, h0)`

(a ufunc) computes the Heaviside
function:

```
{ 0 if x < 0,
heaviside(x, h0) = { h0 if x == 0,
{ 1 if x > 0.
```

`np.block`

function for creating blocked arrays¶

Add a new `block`

function to the current stacking functions `vstack`

,
`hstack`

, and `stack`

. This allows concatenation across multiple axes
simultaneously, with a similar syntax to array creation, but where elements
can themselves be arrays. For instance:

```
>>> A = np.eye(2) * 2
>>> B = np.eye(3) * 3
>>> np.block([
... [A, np.zeros((2, 3))],
... [np.ones((3, 2)), B ]
... ])
array([[ 2., 0., 0., 0., 0.],
[ 0., 2., 0., 0., 0.],
[ 1., 1., 3., 0., 0.],
[ 1., 1., 0., 3., 0.],
[ 1., 1., 0., 0., 3.]])
```

While primarily useful for block matrices, this works for arbitrary dimensions of arrays.

It is similar to Matlab’s square bracket notation for creating block matrices.

`isin`

function, improving on `in1d`

¶

The new function `isin`

tests whether each element of an N-dimensonal
array is present anywhere within a second array. It is an enhancement
of `in1d`

that preserves the shape of the first array.

#### Temporary elision¶

On platforms providing the `backtrace`

function NumPy will try to avoid
creating temporaries in expression involving basic numeric types.
For example `d = a + b + c`

is transformed to `d = a + b; d += c`

which can
improve performance for large arrays as less memory bandwidth is required to
perform the operation.

`axes`

argument for `unique`

¶

In an N-dimensional array, the user can now choose the axis along which to look
for duplicate N-1-dimensional elements using `numpy.unique`

. The original
behaviour is recovered if `axis=None`

(default).

`np.gradient`

now supports unevenly spaced data¶

Users can now specify a not-constant spacing for data.
In particular `np.gradient`

can now take:

- A single scalar to specify a sample distance for all dimensions.
- N scalars to specify a constant sample distance for each dimension.
i.e.
`dx`

,`dy`

,`dz`

, … - N arrays to specify the coordinates of the values along each dimension of F. The length of the array must match the size of the corresponding dimension
- Any combination of N scalars/arrays with the meaning of 2. and 3.

This means that, e.g., it is now possible to do the following:

```
>>> f = np.array([[1, 2, 6], [3, 4, 5]], dtype=np.float)
>>> dx = 2.
>>> y = [1., 1.5, 3.5]
>>> np.gradient(f, dx, y)
[array([[ 1. , 1. , -0.5], [ 1. , 1. , -0.5]]),
array([[ 2. , 2. , 2. ], [ 2. , 1.7, 0.5]])]
```

#### Support for returning arrays of arbitrary dimensions in `apply_along_axis`

¶

Previously, only scalars or 1D arrays could be returned by the function passed
to `apply_along_axis`

. Now, it can return an array of any dimensionality
(including 0D), and the shape of this array replaces the axis of the array
being iterated over.

`.ndim`

property added to `dtype`

to complement `.shape`

¶

For consistency with `ndarray`

and `broadcast`

, `d.ndim`

is a shorthand
for `len(d.shape)`

.

#### Support for tracemalloc in Python 3.6¶

NumPy now supports memory tracing with tracemalloc module of Python 3.6 or
newer. Memory allocations from NumPy are placed into the domain defined by
`numpy.lib.tracemalloc_domain`

.
Note that NumPy allocation will not show up in tracemalloc of earlier Python
versions.

#### NumPy may be built with relaxed stride checking debugging¶

Setting NPY_RELAXED_STRIDES_DEBUG=1 in the environment when relaxed stride checking is enabled will cause NumPy to be compiled with the affected strides set to the maximum value of npy_intp in order to help detect invalid usage of the strides in downstream projects. When enabled, invalid usage often results in an error being raised, but the exact type of error depends on the details of the code. TypeError and OverflowError have been observed in the wild.

It was previously the case that this option was disabled for releases and enabled in master and changing between the two required editing the code. It is now disabled by default but can be enabled for test builds.

### Improvements¶

#### Ufunc behavior for overlapping inputs¶

Operations where ufunc input and output operands have memory overlap produced undefined results in previous NumPy versions, due to data dependency issues. In NumPy 1.13.0, results from such operations are now defined to be the same as for equivalent operations where there is no memory overlap.

Operations affected now make temporary copies, as needed to eliminate data dependency. As detecting these cases is computationally expensive, a heuristic is used, which may in rare cases result to needless temporary copies. For operations where the data dependency is simple enough for the heuristic to analyze, temporary copies will not be made even if the arrays overlap, if it can be deduced copies are not necessary. As an example,``np.add(a, b, out=a)`` will not involve copies.

To illustrate a previously undefined operation:

```
>>> x = np.arange(16).astype(float)
>>> np.add(x[1:], x[:-1], out=x[1:])
```

In NumPy 1.13.0 the last line is guaranteed to be equivalent to:

```
>>> np.add(x[1:].copy(), x[:-1].copy(), out=x[1:])
```

A similar operation with simple non-problematic data dependence is:

```
>>> x = np.arange(16).astype(float)
>>> np.add(x[1:], x[:-1], out=x[:-1])
```

It will continue to produce the same results as in previous NumPy versions, and will not involve unnecessary temporary copies.

The change applies also to in-place binary operations, for example:

```
>>> x = np.random.rand(500, 500)
>>> x += x.T
```

This statement is now guaranteed to be equivalent to `x[...] = x + x.T`

,
whereas in previous NumPy versions the results were undefined.

#### Partial support for 64-bit f2py extensions with MinGW¶

Extensions that incorporate Fortran libraries can now be built using the free MinGW toolset, also under Python 3.5. This works best for extensions that only do calculations and uses the runtime modestly (reading and writing from files, for instance). Note that this does not remove the need for Mingwpy; if you make extensive use of the runtime, you will most likely run into issues. Instead, it should be regarded as a band-aid until Mingwpy is fully functional.

Extensions can also be compiled using the MinGW toolset using the runtime library from the (moveable) WinPython 3.4 distribution, which can be useful for programs with a PySide1/Qt4 front-end.

#### Performance improvements for `packbits`

and `unpackbits`

¶

The functions `numpy.packbits`

with boolean input and `numpy.unpackbits`

have
been optimized to be a significantly faster for contiguous data.

#### Fix for PPC long double floating point information¶

In previous versions of NumPy, the `finfo`

function returned invalid
information about the double double format of the `longdouble`

float type
on Power PC (PPC). The invalid values resulted from the failure of the NumPy
algorithm to deal with the variable number of digits in the significand
that are a feature of *PPC long doubles*. This release by-passes the failing
algorithm by using heuristics to detect the presence of the PPC double double
format. A side-effect of using these heuristics is that the `finfo`

function is faster than previous releases.

#### Better default repr for `ndarray`

subclasses¶

Subclasses of ndarray with no `repr`

specialization now correctly indent
their data and type lines.

#### More reliable comparisons of masked arrays¶

Comparisons of masked arrays were buggy for masked scalars and failed for
structured arrays with dimension higher than one. Both problems are now
solved. In the process, it was ensured that in getting the result for a
structured array, masked fields are properly ignored, i.e., the result is equal
if all fields that are non-masked in both are equal, thus making the behaviour
identical to what one gets by comparing an unstructured masked array and then
doing `.all()`

over some axis.

#### np.matrix with booleans elements can now be created using the string syntax¶

`np.matrix`

failed whenever one attempts to use it with booleans, e.g.,
`np.matrix('True')`

. Now, this works as expected.

#### More `linalg`

operations now accept empty vectors and matrices¶

All of the following functions in `np.linalg`

now work when given input
arrays with a 0 in the last two dimensions: `det`

, `slogdet`

, `pinv`

,
`eigvals`

, `eigvalsh`

, `eig`

, `eigh`

.

#### Bundled version of LAPACK is now 3.2.2¶

NumPy comes bundled with a minimal implementation of lapack for systems without
a lapack library installed, under the name of `lapack_lite`

. This has been
upgraded from LAPACK 3.0.0 (June 30, 1999) to LAPACK 3.2.2 (June 30, 2010). See
the LAPACK changelogs for details on the all the changes this entails.

While no new features are exposed through `numpy`

, this fixes some bugs
regarding “workspace” sizes, and in some places may use faster algorithms.

`reduce`

of `np.hypot.reduce`

and `np.logical_xor`

allowed in more cases¶

This now works on empty arrays, returning 0, and can reduce over multiple axes.
Previously, a `ValueError`

was thrown in these cases.

#### Better `repr`

of object arrays¶

Object arrays that contain themselves no longer cause a recursion error.

Object arrays that contain `list`

objects are now printed in a way that makes
clear the difference between a 2d object array, and a 1d object array of lists.

### Changes¶

`argsort`

on masked arrays takes the same default arguments as `sort`

¶

By default, `argsort`

now places the masked values at the end of the sorted
array, in the same way that `sort`

already did. Additionally, the
`end_with`

argument is added to `argsort`

, for consistency with `sort`

.
Note that this argument is not added at the end, so breaks any code that
passed `fill_value`

as a positional argument.

`average`

now preserves subclasses¶

For ndarray subclasses, `numpy.average`

will now return an instance of the
subclass, matching the behavior of most other NumPy functions such as `mean`

.
As a consequence, also calls that returned a scalar may now return a subclass
array scalar.

`array == None`

and `array != None`

do element-wise comparison¶

Previously these operations returned scalars `False`

and `True`

respectively.

`np.equal, np.not_equal`

for object arrays ignores object identity¶

Previously, these functions always treated identical objects as equal. This had the effect of overriding comparison failures, comparison of objects that did not return booleans, such as np.arrays, and comparison of objects where the results differed from object identity, such as NaNs.

#### Boolean indexing changes¶

- Boolean array-likes (such as lists of python bools) are always treated as boolean indexes.
- Boolean scalars (including python
`True`

) are legal boolean indexes and never treated as integers. - Boolean indexes must match the dimension of the axis that they index.
- Boolean indexes used on the lhs of an assignment must match the dimensions of the rhs.
- Boolean indexing into scalar arrays return a new 1-d array. This means that
`array(1)[array(True)]`

gives`array([1])`

and not the original array.

`np.random.multivariate_normal`

behavior with bad covariance matrix¶

It is now possible to adjust the behavior the function will have when dealing with the covariance matrix by using two new keyword arguments:

`tol`

can be used to specify a tolerance to use when checking that the covariance matrix is positive semidefinite.`check_valid`

can be used to configure what the function will do in the presence of a matrix that is not positive semidefinite. Valid options are`ignore`

,`warn`

and`raise`

. The default value,`warn`

keeps the the behavior used on previous releases.

`assert_array_less`

compares `np.inf`

and `-np.inf`

now¶

Previously, `np.testing.assert_array_less`

ignored all infinite values. This
is not the expected behavior both according to documentation and intuitively.
Now, -inf < x < inf is considered `True`

for any real number x and all
other cases fail.

`assert_array_`

and masked arrays `assert_equal`

hide less warnings¶

Some warnings that were previously hidden by the `assert_array_`

functions are not hidden anymore. In most cases the warnings should be
correct and, should they occur, will require changes to the tests using
these functions.
For the masked array `assert_equal`

version, warnings may occur when
comparing NaT. The function presently does not handle NaT or NaN
specifically and it may be best to avoid it at this time should a warning
show up due to this change.

`offset`

attribute value in `memmap`

objects¶

The `offset`

attribute in a `memmap`

object is now set to the
offset into the file. This is a behaviour change only for offsets
greater than `mmap.ALLOCATIONGRANULARITY`

.

`np.real`

and `np.imag`

return scalars for scalar inputs¶

Previously, `np.real`

and `np.imag`

used to return array objects when
provided a scalar input, which was inconsistent with other functions like
`np.angle`

and `np.conj`

.

#### The polynomial convenience classes cannot be passed to ufuncs¶

The ABCPolyBase class, from which the convenience classes are derived, sets
`__array_ufun__ = None`

in order of opt out of ufuncs. If a polynomial
convenience class instance is passed as an argument to a ufunc, a `TypeError`

will now be raised.

#### Output arguments to ufuncs can be tuples also for ufunc methods¶

For calls to ufuncs, it was already possible, and recommended, to use an
`out`

argument with a tuple for ufuncs with multiple outputs. This has now
been extended to output arguments in the `reduce`

, `accumulate`

, and
`reduceat`

methods. This is mostly for compatibility with `__array_ufunc`

;
there are no ufuncs yet that have more than one output.

## NumPy 1.12.1 Release Notes¶

NumPy 1.12.1 supports Python 2.7 and 3.4 - 3.6 and fixes bugs and regressions found in NumPy 1.12.0. In particular, the regression in f2py constant parsing is fixed. Wheels for Linux, Windows, and OSX can be found on pypi,

### Bugs Fixed¶

- BUG: Fix wrong future nat warning and equiv type logic error…
- BUG: Fix wrong masked median for some special cases
- DOC: Place np.average in inline code
- TST: Work around isfinite inconsistency on i386
- BUG: Guard against replacing constants without ‘_’ spec in f2py.
- BUG: Fix mean for float 16 non-array inputs for 1.12
- BUG: Fix calling python api with error set and minor leaks for…
- BUG: Make iscomplexobj compatible with custom dtypes again
- BUG: Fix undefined behaviour induced by bad __array_wrap__
- BUG: Fix MaskedArray.__setitem__
- BUG: PPC64el machines are POWER for Fortran in f2py
- BUG: Look up methods on MaskedArray in
*_frommethod* - BUG: Remove extra digit in binary_repr at limit
- BUG: Fix deepcopy regression for empty arrays.
- BUG: Fix ma.median for empty ndarrays

## NumPy 1.12.0 Release Notes¶

This release supports Python 2.7 and 3.4 - 3.6.

### Highlights¶

The NumPy 1.12.0 release contains a large number of fixes and improvements, but few that stand out above all others. That makes picking out the highlights somewhat arbitrary but the following may be of particular interest or indicate areas likely to have future consequences.

- Order of operations in
`np.einsum`

can now be optimized for large speed improvements. - New
`signature`

argument to`np.vectorize`

for vectorizing with core dimensions. - The
`keepdims`

argument was added to many functions. - New context manager for testing warnings
- Support for BLIS in numpy.distutils
- Much improved support for PyPy (not yet finished)

### Dropped Support¶

- Support for Python 2.6, 3.2, and 3.3 has been dropped.

### Added Support¶

- Support for PyPy 2.7 v5.6.0 has been added. While not complete (nditer
`updateifcopy`

is not supported yet), this is a milestone for PyPy’s C-API compatibility layer.

### Build System Changes¶

- Library order is preserved, instead of being reordered to match that of the directories.

### Deprecations¶

#### Assignment of ndarray object’s `data`

attribute¶

Assigning the ‘data’ attribute is an inherently unsafe operation as pointed out in gh-7083. Such a capability will be removed in the future.

#### Unsafe int casting of the num attribute in `linspace`

¶

`np.linspace`

now raises DeprecationWarning when num cannot be safely
interpreted as an integer.

#### Insufficient bit width parameter to `binary_repr`

¶

If a ‘width’ parameter is passed into `binary_repr`

that is insufficient to
represent the number in base 2 (positive) or 2’s complement (negative) form,
the function used to silently ignore the parameter and return a representation
using the minimal number of bits needed for the form in question. Such behavior
is now considered unsafe from a user perspective and will raise an error in the
future.

### Future Changes¶

- In 1.13 NAT will always compare False except for
`NAT != NAT`

, which will be True. In short, NAT will behave like NaN - In 1.13
`np.average`

will preserve subclasses, to match the behavior of most other numpy functions such as np.mean. In particular, this means calls which returned a scalar may return a 0-d subclass object instead.

#### Multiple-field manipulation of structured arrays¶

In 1.13 the behavior of structured arrays involving multiple fields will change in two ways:

First, indexing a structured array with multiple fields (eg,
`arr[['f1', 'f3']]`

) will return a view into the original array in 1.13,
instead of a copy. Note the returned view will have extra padding bytes
corresponding to intervening fields in the original array, unlike the copy in
1.12, which will affect code such as `arr[['f1', 'f3']].view(newdtype)`

.

Second, for numpy versions 1.6 to 1.12 assignment between structured arrays occurs “by field name”: Fields in the destination array are set to the identically-named field in the source array or to 0 if the source does not have a field:

```
>>> a = np.array([(1,2),(3,4)], dtype=[('x', 'i4'), ('y', 'i4')])
>>> b = np.ones(2, dtype=[('z', 'i4'), ('y', 'i4'), ('x', 'i4')])
>>> b[:] = a
>>> b
array([(0, 2, 1), (0, 4, 3)],
dtype=[('z', '<i4'), ('y', '<i4'), ('x', '<i4')])
```

In 1.13 assignment will instead occur “by position”: The Nth field of the
destination will be set to the Nth field of the source regardless of field
name. The old behavior can be obtained by using indexing to reorder the fields
before
assignment, e.g., `b[['x', 'y']] = a[['y', 'x']]`

.

### Compatibility notes¶

#### DeprecationWarning to error¶

- Indexing with floats raises
`IndexError`

, e.g., a[0, 0.0]. - Indexing with non-integer array_like raises
`IndexError`

, e.g.,`a['1', '2']`

- Indexing with multiple ellipsis raises
`IndexError`

, e.g.,`a[..., ...]`

. - Non-integers used as index values raise
`TypeError`

, e.g., in`reshape`

,`take`

, and specifying reduce axis.

#### FutureWarning to changed behavior¶

`np.full`

now returns an array of the fill-value’s dtype if no dtype is given, instead of defaulting to float.`np.average`

will emit a warning if the argument is a subclass of ndarray, as the subclass will be preserved starting in 1.13. (see Future Changes)

`power`

and `**`

raise errors for integer to negative integer powers¶

The previous behavior depended on whether numpy scalar integers or numpy integer arrays were involved.

For arrays

- Zero to negative integer powers returned least integral value.
- Both 1, -1 to negative integer powers returned correct values.
- The remaining integers returned zero when raised to negative integer powers.

For scalars

- Zero to negative integer powers returned least integral value.
- Both 1, -1 to negative integer powers returned correct values.
- The remaining integers sometimes returned zero, sometimes the correct float depending on the integer type combination.

All of these cases now raise a `ValueError`

except for those integer
combinations whose common type is float, for instance uint64 and int8. It was
felt that a simple rule was the best way to go rather than have special
exceptions for the integer units. If you need negative powers, use an inexact
type.

#### Relaxed stride checking is the default¶

This will have some impact on code that assumed that `F_CONTIGUOUS`

and
`C_CONTIGUOUS`

were mutually exclusive and could be set to determine the
default order for arrays that are now both.

#### The `np.percentile`

‘midpoint’ interpolation method fixed for exact indices¶

The ‘midpoint’ interpolator now gives the same result as ‘lower’ and ‘higher’ when the two coincide. Previous behavior of ‘lower’ + 0.5 is fixed.

`keepdims`

kwarg is passed through to user-class methods¶

numpy functions that take a `keepdims`

kwarg now pass the value
through to the corresponding methods on ndarray sub-classes. Previously the
`keepdims`

keyword would be silently dropped. These functions now have
the following behavior:

- If user does not provide
`keepdims`

, no keyword is passed to the underlying method. - Any user-provided value of
`keepdims`

is passed through as a keyword argument to the method.

This will raise in the case where the method does not support a
`keepdims`

kwarg and the user explicitly passes in `keepdims`

.

The following functions are changed: `sum`

, `product`

,
`sometrue`

, `alltrue`

, `any`

, `all`

, `amax`

, `amin`

,
`prod`

, `mean`

, `std`

, `var`

, `nanmin`

, `nanmax`

,
`nansum`

, `nanprod`

, `nanmean`

, `nanmedian`

, `nanvar`

,
`nanstd`

`bitwise_and`

identity changed¶

The previous identity was 1, it is now -1. See entry in Improvements for more explanation.

#### ma.median warns and returns nan when unmasked invalid values are encountered¶

Similar to unmasked median the masked median *ma.median* now emits a Runtime
warning and returns *NaN* in slices where an unmasked *NaN* is present.

#### Greater consistency in `assert_almost_equal`

¶

The precision check for scalars has been changed to match that for arrays. It is now:

```
abs(actual - desired) < 1.5 * 10**(-decimal)
```

Note that this is looser than previously documented, but agrees with the
previous implementation used in `assert_array_almost_equal`

. Due to the
change in implementation some very delicate tests may fail that did not
fail before.

`NoseTester`

behaviour of warnings during testing¶

When `raise_warnings="develop"`

is given, all uncaught warnings will now
be considered a test failure. Previously only selected ones were raised.
Warnings which are not caught or raised (mostly when in release mode)
will be shown once during the test cycle similar to the default python
settings.

`assert_warns`

and `deprecated`

decorator more specific¶

The `assert_warns`

function and context manager are now more specific
to the given warning category. This increased specificity leads to them
being handled according to the outer warning settings. This means that
no warning may be raised in cases where a wrong category warning is given
and ignored outside the context. Alternatively the increased specificity
may mean that warnings that were incorrectly ignored will now be shown
or raised. See also the new `suppress_warnings`

context manager.
The same is true for the `deprecated`

decorator.

#### C API¶

No changes.

### New Features¶

#### Writeable keyword argument for `as_strided`

¶

`np.lib.stride_tricks.as_strided`

now has a `writeable`

keyword argument. It can be set to False when no write operation
to the returned array is expected to avoid accidental
unpredictable writes.

`axes`

keyword argument for `rot90`

¶

The `axes`

keyword argument in `rot90`

determines the plane in which the
array is rotated. It defaults to `axes=(0,1)`

as in the original function.

#### Generalized `flip`

¶

`flipud`

and `fliplr`

reverse the elements of an array along axis=0 and
axis=1 respectively. The newly added `flip`

function reverses the elements of
an array along any given axis.

`np.count_nonzero`

now has an`axis`

parameter, allowing non-zero counts to be generated on more than just a flattened array object.

#### BLIS support in `numpy.distutils`

¶

Building against the BLAS implementation provided by the BLIS library is now
supported. See the `[blis]`

section in `site.cfg.example`

(in the root of
the numpy repo or source distribution).

#### Hook in `numpy/__init__.py`

to run distribution-specific checks¶

Binary distributions of numpy may need to run specific hardware checks or load specific libraries during numpy initialization. For example, if we are distributing numpy with a BLAS library that requires SSE2 instructions, we would like to check the machine on which numpy is running does have SSE2 in order to give an informative error.

Add a hook in `numpy/__init__.py`

to import a `numpy/_distributor_init.py`

file that will remain empty (bar a docstring) in the standard numpy source,
but that can be overwritten by people making binary distributions of numpy.

#### New nanfunctions `nancumsum`

and `nancumprod`

added¶

Nan-functions `nancumsum`

and `nancumprod`

have been added to
compute `cumsum`

and `cumprod`

by ignoring nans.

`np.interp`

can now interpolate complex values¶

`np.lib.interp(x, xp, fp)`

now allows the interpolated array `fp`

to be complex and will interpolate at `complex128`

precision.

#### New polynomial evaluation function `polyvalfromroots`

added¶

The new function `polyvalfromroots`

evaluates a polynomial at given points
from the roots of the polynomial. This is useful for higher order polynomials,
where expansion into polynomial coefficients is inaccurate at machine
precision.

#### New array creation function `geomspace`

added¶

The new function `geomspace`

generates a geometric sequence. It is similar
to `logspace`

, but with start and stop specified directly:
`geomspace(start, stop)`

behaves the same as
`logspace(log10(start), log10(stop))`

.

#### New context manager for testing warnings¶

A new context manager `suppress_warnings`

has been added to the testing
utils. This context manager is designed to help reliably test warnings.
Specifically to reliably filter/ignore warnings. Ignoring warnings
by using an “ignore” filter in Python versions before 3.4.x can quickly
result in these (or similar) warnings not being tested reliably.

The context manager allows to filter (as well as record) warnings similar
to the `catch_warnings`

context, but allows for easier specificity.
Also printing warnings that have not been filtered or nesting the
context manager will work as expected. Additionally, it is possible
to use the context manager as a decorator which can be useful when
multiple tests give need to hide the same warning.

#### New masked array functions `ma.convolve`

and `ma.correlate`

added¶

These functions wrapped the non-masked versions, but propagate through masked values. There are two different propagation modes. The default causes masked values to contaminate the result with masks, but the other mode only outputs masks if there is no alternative.

#### New `float_power`

ufunc¶

The new `float_power`

ufunc is like the `power`

function except all
computation is done in a minimum precision of float64. There was a long
discussion on the numpy mailing list of how to treat integers to negative
integer powers and a popular proposal was that the `__pow__`

operator should
always return results of at least float64 precision. The `float_power`

function implements that option. Note that it does not support object arrays.

`np.loadtxt`

now supports a single integer as `usecol`

argument¶

Instead of using `usecol=(n,)`

to read the nth column of a file
it is now allowed to use `usecol=n`

. Also the error message is
more user friendly when a non-integer is passed as a column index.

#### Improved automated bin estimators for `histogram`

¶

Added ‘doane’ and ‘sqrt’ estimators to `histogram`

via the `bins`

argument. Added support for range-restricted histograms with automated
bin estimation.

`np.roll`

can now roll multiple axes at the same time¶

The `shift`

and `axis`

arguments to `roll`

are now broadcast against each
other, and each specified axis is shifted accordingly.

#### The `__complex__`

method has been implemented for the ndarrays¶

Calling `complex()`

on a size 1 array will now cast to a python
complex.

`pathlib.Path`

objects now supported¶

The standard `np.load`

, `np.save`

, `np.loadtxt`

, `np.savez`

, and similar
functions can now take `pathlib.Path`

objects as an argument instead of a
filename or open file object.

#### New `bits`

attribute for `np.finfo`

¶

This makes `np.finfo`

consistent with `np.iinfo`

which already has that
attribute.

#### New `signature`

argument to `np.vectorize`

¶

This argument allows for vectorizing user defined functions with core
dimensions, in the style of NumPy’s
generalized universal functions. This allows
for vectorizing a much broader class of functions. For example, an arbitrary
distance metric that combines two vectors to produce a scalar could be
vectorized with `signature='(n),(n)->()'`

. See `np.vectorize`

for full
details.

#### Emit py3kwarnings for division of integer arrays¶

To help people migrate their code bases from Python 2 to Python 3, the python interpreter has a handy option -3, which issues warnings at runtime. One of its warnings is for integer division:

```
$ python -3 -c "2/3"
-c:1: DeprecationWarning: classic int division
```

In Python 3, the new integer division semantics also apply to numpy arrays. With this version, numpy will emit a similar warning:

```
$ python -3 -c "import numpy as np; np.array(2)/np.array(3)"
-c:1: DeprecationWarning: numpy: classic int division
```

#### numpy.sctypes now includes bytes on Python3 too¶

Previously, it included str (bytes) and unicode on Python2, but only str (unicode) on Python3.

### Improvements¶

`bitwise_and`

identity changed¶

The previous identity was 1 with the result that all bits except the LSB were masked out when the reduce method was used. The new identity is -1, which should work properly on twos complement machines as all bits will be set to one.

#### Generalized Ufuncs will now unlock the GIL¶

Generalized Ufuncs, including most of the linalg module, will now unlock the Python global interpreter lock.

#### Caches in *np.fft* are now bounded in total size and item count¶

The caches in *np.fft* that speed up successive FFTs of the same length can no
longer grow without bounds. They have been replaced with LRU (least recently
used) caches that automatically evict no longer needed items if either the
memory size or item count limit has been reached.

#### Improved handling of zero-width string/unicode dtypes¶

Fixed several interfaces that explicitly disallowed arrays with zero-width
string dtypes (i.e. `dtype('S0')`

or `dtype('U0')`

, and fixed several
bugs where such dtypes were not handled properly. In particular, changed
`ndarray.__new__`

to not implicitly convert `dtype('S0')`

to
`dtype('S1')`

(and likewise for unicode) when creating new arrays.

#### Integer ufuncs vectorized with AVX2¶

If the cpu supports it at runtime the basic integer ufuncs now use AVX2 instructions. This feature is currently only available when compiled with GCC.

#### Order of operations optimization in `np.einsum`

¶

`np.einsum`

now supports the `optimize`

argument which will optimize the
order of contraction. For example, `np.einsum`

would complete the chain dot
example `np.einsum(‘ij,jk,kl->il’, a, b, c)`

in a single pass which would
scale like `N^4`

; however, when `optimize=True`

`np.einsum`

will create
an intermediate array to reduce this scaling to `N^3`

or effectively
`np.dot(a, b).dot(c)`

. Usage of intermediate tensors to reduce scaling has
been applied to the general einsum summation notation. See `np.einsum_path`

for more details.

#### quicksort has been changed to an introsort¶

The quicksort kind of `np.sort`

and `np.argsort`

is now an introsort which
is regular quicksort but changing to a heapsort when not enough progress is
made. This retains the good quicksort performance while changing the worst case
runtime from `O(N^2)`

to `O(N*log(N))`

.

`ediff1d`

improved performance and subclass handling¶

The ediff1d function uses an array instead on a flat iterator for the subtraction. When to_begin or to_end is not None, the subtraction is performed in place to eliminate a copy operation. A side effect is that certain subclasses are handled better, namely astropy.Quantity, since the complete array is created, wrapped, and then begin and end values are set, instead of using concatenate.

#### Improved precision of `ndarray.mean`

for float16 arrays¶

The computation of the mean of float16 arrays is now carried out in float32 for improved precision. This should be useful in packages such as Theano where the precision of float16 is adequate and its smaller footprint is desirable.

### Changes¶

#### All array-like methods are now called with keyword arguments in fromnumeric.py¶

Internally, many array-like methods in fromnumeric.py were being called with positional arguments instead of keyword arguments as their external signatures were doing. This caused a complication in the downstream ‘pandas’ library that encountered an issue with ‘numpy’ compatibility. Now, all array-like methods in this module are called with keyword arguments instead.

#### Operations on np.memmap objects return numpy arrays in most cases¶

Previously operations on a memmap object would misleadingly return a memmap
instance even if the result was actually not memmapped. For example,
`arr + 1`

or `arr + arr`

would return memmap instances, although no memory
from the output array is memmapped. Version 1.12 returns ordinary numpy arrays
from these operations.

Also, reduction of a memmap (e.g. `.sum(axis=None`

) now returns a numpy
scalar instead of a 0d memmap.

#### stacklevel of warnings increased¶

The stacklevel for python based warnings was increased so that most warnings
will report the offending line of the user code instead of the line the
warning itself is given. Passing of stacklevel is now tested to ensure that
new warnings will receive the `stacklevel`

argument.

This causes warnings with the “default” or “module” filter to be shown once for every offending user code line or user module instead of only once. On python versions before 3.4, this can cause warnings to appear that were falsely ignored before, which may be surprising especially in test suits.

## NumPy 1.11.3 Release Notes¶

Numpy 1.11.3 fixes a bug that leads to file corruption when very large files
opened in append mode are used in `ndarray.tofile`

. It supports Python
versions 2.6 - 2.7 and 3.2 - 3.5. Wheels for Linux, Windows, and OS X can be
found on PyPI.

### Contributors to maintenance/1.11.3¶

A total of 2 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

- Charles Harris
- Pavel Potocek +

## NumPy 1.11.2 Release Notes¶

Numpy 1.11.2 supports Python 2.6 - 2.7 and 3.2 - 3.5. It fixes bugs and regressions found in Numpy 1.11.1 and includes several build related improvements. Wheels for Linux, Windows, and OS X can be found on PyPI.

### Pull Requests Merged¶

Fixes overridden by later merges and release notes updates are omitted.

- #7736 BUG: Many functions silently drop ‘keepdims’ kwarg.
- #7738 ENH: Add extra kwargs and update doc of many MA methods.
- #7778 DOC: Update Numpy 1.11.1 release notes.
- #7793 BUG: MaskedArray.count treats negative axes incorrectly.
- #7816 BUG: Fix array too big error for wide dtypes.
- #7821 BUG: Make sure npy_mul_with_overflow_<type> detects overflow.
- #7824 MAINT: Allocate fewer bytes for empty arrays.
- #7847 MAINT,DOC: Fix some imp module uses and update f2py.compile docstring.
- #7849 MAINT: Fix remaining uses of deprecated Python imp module.
- #7851 BLD: Fix ATLAS version detection.
- #7896 BUG: Construct ma.array from np.array which contains padding.
- #7904 BUG: Fix float16 type not being called due to wrong ordering.
- #7917 BUG: Production install of numpy should not require nose.
- #7919 BLD: Fixed MKL detection for recent versions of this library.
- #7920 BUG: Fix for issue #7835 (ma.median of 1d).
- #7932 BUG: Monkey-patch _msvccompile.gen_lib_option like other compilers.
- #7939 BUG: Check for HAVE_LDOUBLE_DOUBLE_DOUBLE_LE in npy_math_complex.
- #7953 BUG: Guard against buggy comparisons in generic quicksort.
- #7954 BUG: Use keyword arguments to initialize Extension base class.
- #7955 BUG: Make sure numpy globals keep identity after reload.
- #7972 BUG: MSVCCompiler grows ‘lib’ & ‘include’ env strings exponentially.
- #8005 BLD: Remove __NUMPY_SETUP__ from builtins at end of setup.py.
- #8010 MAINT: Remove leftover imp module imports.
- #8020 BUG: Fix return of np.ma.count if keepdims is True and axis is None.
- #8024 BUG: Fix numpy.ma.median.
- #8031 BUG: Fix np.ma.median with only one non-masked value.
- #8044 BUG: Fix bug in NpyIter buffering with discontinuous arrays.

## NumPy 1.11.1 Release Notes¶

Numpy 1.11.1 supports Python 2.6 - 2.7 and 3.2 - 3.5. It fixes bugs and regressions found in Numpy 1.11.0 and includes several build related improvements. Wheels for Linux, Windows, and OSX can be found on pypi.

### Fixes Merged¶

- #7506 BUG: Make sure numpy imports on python 2.6 when nose is unavailable.
- #7530 BUG: Floating exception with invalid axis in np.lexsort.
- #7535 BUG: Extend glibc complex trig functions blacklist to glibc < 2.18.
- #7551 BUG: Allow graceful recovery for no compiler.
- #7558 BUG: Constant padding expected wrong type in constant_values.
- #7578 BUG: Fix OverflowError in Python 3.x. in swig interface.
- #7590 BLD: Fix configparser.InterpolationSyntaxError.
- #7597 BUG: Make np.ma.take work on scalars.
- #7608 BUG: linalg.norm(): Don’t convert object arrays to float.
- #7638 BLD: Correct C compiler customization in system_info.py.
- #7654 BUG: ma.median of 1d array should return a scalar.
- #7656 BLD: Remove hardcoded Intel compiler flag -xSSE4.2.
- #7660 BUG: Temporary fix for str(mvoid) for object field types.
- #7665 BUG: Fix incorrect printing of 1D masked arrays.
- #7670 BUG: Correct initial index estimate in histogram.
- #7671 BUG: Boolean assignment no GIL release when transfer needs API.
- #7676 BUG: Fix handling of right edge of final histogram bin.
- #7680 BUG: Fix np.clip bug NaN handling for Visual Studio 2015.
- #7724 BUG: Fix segfaults in np.random.shuffle.
- #7731 MAINT: Change mkl_info.dir_env_var from MKL to MKLROOT.
- #7737 BUG: Fix issue on OS X with Python 3.x, npymath.ini not installed.

## NumPy 1.11.0 Release Notes¶

This release supports Python 2.6 - 2.7 and 3.2 - 3.5 and contains a number of enhancements and improvements. Note also the build system changes listed below as they may have subtle effects.

No Windows (TM) binaries are provided for this release due to a broken toolchain. One of the providers of Python packages for Windows (TM) is your best bet.

### Highlights¶

Details of these improvements can be found below.

- The datetime64 type is now timezone naive.
- A dtype parameter has been added to
`randint`

. - Improved detection of two arrays possibly sharing memory.
- Automatic bin size estimation for
`np.histogram`

. - Speed optimization of A @ A.T and dot(A, A.T).
- New function
`np.moveaxis`

for reordering array axes.

### Build System Changes¶

- Numpy now uses
`setuptools`

for its builds instead of plain distutils. This fixes usage of`install_requires='numpy'`

in the`setup.py`

files of projects that depend on Numpy (see gh-6551). It potentially affects the way that build/install methods for Numpy itself behave though. Please report any unexpected behavior on the Numpy issue tracker. - Bento build support and related files have been removed.
- Single file build support and related files have been removed.

### Future Changes¶

The following changes are scheduled for Numpy 1.12.0.

- Support for Python 2.6, 3.2, and 3.3 will be dropped.
- Relaxed stride checking will become the default. See the 1.8.0 release notes for a more extended discussion of what this change implies.
- The behavior of the datetime64 “not a time” (NaT) value will be changed to match that of floating point “not a number” (NaN) values: all comparisons involving NaT will return False, except for NaT != NaT which will return True.
- Indexing with floats will raise IndexError, e.g., a[0, 0.0].
- Indexing with non-integer array_like will raise
`IndexError`

, e.g.,`a['1', '2']`

- Indexing with multiple ellipsis will raise
`IndexError`

, e.g.,`a[..., ...]`

. - Non-integers used as index values will raise
`TypeError`

, e.g., in`reshape`

,`take`

, and specifying reduce axis.

In a future release the following changes will be made.

- The
`rand`

function exposed in`numpy.testing`

will be removed. That function is left over from early Numpy and was implemented using the Python random module. The random number generators from`numpy.random`

should be used instead. - The
`ndarray.view`

method will only allow c_contiguous arrays to be viewed using a dtype of different size causing the last dimension to change. That differs from the current behavior where arrays that are f_contiguous but not c_contiguous can be viewed as a dtype type of different size causing the first dimension to change. - Slicing a
`MaskedArray`

will return views of both data**and**mask. Currently the mask is copy-on-write and changes to the mask in the slice do not propagate to the original mask. See the FutureWarnings section below for details.

### Compatibility notes¶

#### datetime64 changes¶

In prior versions of NumPy the experimental datetime64 type always stored times in UTC. By default, creating a datetime64 object from a string or printing it would convert from or to local time:

```
# old behavior
>>>> np.datetime64('2000-01-01T00:00:00')
numpy.datetime64('2000-01-01T00:00:00-0800') # note the timezone offset -08:00
```

A consensus of datetime64 users agreed that this behavior is undesirable
and at odds with how datetime64 is usually used (e.g., by pandas). For most use cases, a timezone naive datetime
type is preferred, similar to the `datetime.datetime`

type in the Python
standard library. Accordingly, datetime64 no longer assumes that input is in
local time, nor does it print local times:

```
>>>> np.datetime64('2000-01-01T00:00:00')
numpy.datetime64('2000-01-01T00:00:00')
```

For backwards compatibility, datetime64 still parses timezone offsets, which it handles by converting to UTC. However, the resulting datetime is timezone naive:

```
>>> np.datetime64('2000-01-01T00:00:00-08')
DeprecationWarning: parsing timezone aware datetimes is deprecated;
this will raise an error in the future
numpy.datetime64('2000-01-01T08:00:00')
```

As a corollary to this change, we no longer prohibit casting between datetimes with date units and datetimes with time units. With timezone naive datetimes, the rule for casting from dates to times is no longer ambiguous.

`linalg.norm`

return type changes¶

The return type of the `linalg.norm`

function is now floating point without
exception. Some of the norm types previously returned integers.

#### polynomial fit changes¶

The various fit functions in the numpy polynomial package no longer accept non-integers for degree specification.

*np.dot* now raises `TypeError`

instead of `ValueError`

¶

This behaviour mimics that of other functions such as `np.inner`

. If the two
arguments cannot be cast to a common type, it could have raised a `TypeError`

or `ValueError`

depending on their order. Now, `np.dot`

will now always
raise a `TypeError`

.

#### FutureWarning to changed behavior¶

- In
`np.lib.split`

an empty array in the result always had dimension`(0,)`

no matter the dimensions of the array being split. This has been changed so that the dimensions will be preserved. A`FutureWarning`

for this change has been in place since Numpy 1.9 but, due to a bug, sometimes no warning was raised and the dimensions were already preserved.

`%`

and `//`

operators¶

These operators are implemented with the `remainder`

and `floor_divide`

functions respectively. Those functions are now based around `fmod`

and are
computed together so as to be compatible with each other and with the Python
versions for float types. The results should be marginally more accurate or
outright bug fixes compared to the previous results, but they may
differ significantly in cases where roundoff makes a difference in the integer
returned by `floor_divide`

. Some corner cases also change, for instance, NaN
is always returned for both functions when the divisor is zero,
`divmod(1.0, inf)`

returns `(0.0, 1.0)`

except on MSVC 2008, and
`divmod(-1.0, inf)`

returns `(-1.0, inf)`

.

#### C API¶

Removed the `check_return`

and `inner_loop_selector`

members of
the `PyUFuncObject`

struct (replacing them with `reserved`

slots
to preserve struct layout). These were never used for anything, so
it’s unlikely that any third-party code is using them either, but we
mention it here for completeness.

#### object dtype detection for old-style classes¶

In python 2, objects which are instances of old-style user-defined classes no
longer automatically count as ‘object’ type in the dtype-detection handler.
Instead, as in python 3, they may potentially count as sequences, but only if
they define both a *__len__* and a *__getitem__* method. This fixes a segfault
and inconsistency between python 2 and 3.

### New Features¶

`np.histogram`

now provides plugin estimators for automatically estimating the optimal number of bins. Passing one of [‘auto’, ‘fd’, ‘scott’, ‘rice’, ‘sturges’] as the argument to ‘bins’ results in the corresponding estimator being used.A benchmark suite using Airspeed Velocity has been added, converting the previous vbench-based one. You can run the suite locally via

`python runtests.py --bench`

. For more details, see`benchmarks/README.rst`

.A new function

`np.shares_memory`

that can check exactly whether two arrays have memory overlap is added.`np.may_share_memory`

also now has an option to spend more effort to reduce false positives.`SkipTest`

and`KnownFailureException`

exception classes are exposed in the`numpy.testing`

namespace. Raise them in a test function to mark the test to be skipped or mark it as a known failure, respectively.`f2py.compile`

has a new`extension`

keyword parameter that allows the fortran extension to be specified for generated temp files. For instance, the files can be specifies to be`*.f90`

. The`verbose`

argument is also activated, it was previously ignored.A

`dtype`

parameter has been added to`np.random.randint`

Random ndarrays of the following types can now be generated:`np.bool`

,`np.int8`

,`np.uint8`

,`np.int16`

,`np.uint16`

,`np.int32`

,`np.uint32`

,`np.int64`

,`np.uint64`

,`np.int_ ``, ``np.intp`

The specification is by precision rather than by C type. Hence, on some platforms

`np.int64`

may be a`long`

instead of`long long`

even if the specified dtype is`long long`

because the two may have the same precision. The resulting type depends on which C type numpy uses for the given precision. The byteorder specification is also ignored, the generated arrays are always in native byte order.A new

`np.moveaxis`

function allows for moving one or more array axes to a new position by explicitly providing source and destination axes. This function should be easier to use than the current`rollaxis`

function as well as providing more functionality.The

`deg`

parameter of the various`numpy.polynomial`

fits has been extended to accept a list of the degrees of the terms to be included in the fit, the coefficients of all other terms being constrained to zero. The change is backward compatible, passing a scalar`deg`

will behave as before.A divmod function for float types modeled after the Python version has been added to the npy_math library.

### Improvements¶

`np.gradient`

now supports an `axis`

argument¶

The `axis`

parameter was added to `np.gradient`

for consistency. It
allows to specify over which axes the gradient is calculated.

`np.lexsort`

now supports arrays with object data-type¶

The function now internally calls the generic `npy_amergesort`

when the
type does not implement a merge-sort kind of `argsort`

method.

`np.ma.core.MaskedArray`

now supports an `order`

argument¶

When constructing a new `MaskedArray`

instance, it can be configured with
an `order`

argument analogous to the one when calling `np.ndarray`

. The
addition of this argument allows for the proper processing of an `order`

argument in several MaskedArray-related utility functions such as
`np.ma.core.array`

and `np.ma.core.asarray`

.

#### Memory and speed improvements for masked arrays¶

Creating a masked array with `mask=True`

(resp. `mask=False`

) now uses
`np.ones`

(resp. `np.zeros`

) to create the mask, which is faster and
avoid a big memory peak. Another optimization was done to avoid a memory
peak and useless computations when printing a masked array.

`ndarray.tofile`

now uses fallocate on linux¶

The function now uses the fallocate system call to reserve sufficient disk space on file systems that support it.

#### Optimizations for operations of the form `A.T @ A`

and `A @ A.T`

¶

Previously, `gemm`

BLAS operations were used for all matrix products. Now,
if the matrix product is between a matrix and its transpose, it will use
`syrk`

BLAS operations for a performance boost. This optimization has been
extended to `@`

, `numpy.dot`

, `numpy.inner`

, and `numpy.matmul`

.

**Note:** Requires the transposed and non-transposed matrices to share data.

`np.testing.assert_warns`

can now be used as a context manager¶

This matches the behavior of `assert_raises`

.

#### Speed improvement for np.random.shuffle¶

`np.random.shuffle`

is now much faster for 1d ndarrays.

### Changes¶

#### Pyrex support was removed from `numpy.distutils`

¶

The method `build_src.generate_a_pyrex_source`

will remain available; it
has been monkeypatched by users to support Cython instead of Pyrex. It’s
recommended to switch to a better supported method of build Cython
extensions though.

`np.broadcast`

can now be called with a single argument¶

The resulting object in that case will simply mimic iteration over a single array. This change obsoletes distinctions like

- if len(x) == 1:
- shape = x[0].shape
- else:
- shape = np.broadcast(*x).shape

Instead, `np.broadcast`

can be used in all cases.

`np.trace`

now respects array subclasses¶

This behaviour mimics that of other functions such as `np.diagonal`

and
ensures, e.g., that for masked arrays `np.trace(ma)`

and `ma.trace()`

give
the same result.

`np.dot`

now raises `TypeError`

instead of `ValueError`

¶

This behaviour mimics that of other functions such as `np.inner`

. If the two
arguments cannot be cast to a common type, it could have raised a `TypeError`

or `ValueError`

depending on their order. Now, `np.dot`

will now always
raise a `TypeError`

.

`linalg.norm`

return type changes¶

The `linalg.norm`

function now does all its computations in floating point
and returns floating results. This change fixes bugs due to integer overflow
and the failure of abs with signed integers of minimum value, e.g., int8(-128).
For consistency, floats are used even where an integer might work.

### Deprecations¶

#### Views of arrays in Fortran order¶

The F_CONTIGUOUS flag was used to signal that views using a dtype that
changed the element size would change the first index. This was always
problematical for arrays that were both F_CONTIGUOUS and C_CONTIGUOUS
because C_CONTIGUOUS took precedence. Relaxed stride checking results in
more such dual contiguous arrays and breaks some existing code as a result.
Note that this also affects changing the dtype by assigning to the dtype
attribute of an array. The aim of this deprecation is to restrict views to
C_CONTIGUOUS arrays at some future time. A work around that is backward
compatible is to use `a.T.view(...).T`

instead. A parameter may also be
added to the view method to explicitly ask for Fortran order views, but
that will not be backward compatible.

#### Invalid arguments for array ordering¶

It is currently possible to pass in arguments for the `order`

parameter in methods like `array.flatten`

or `array.ravel`

that were not one of the following: ‘C’, ‘F’, ‘A’, ‘K’ (note that
all of these possible values are both unicode and case insensitive).
Such behavior will not be allowed in future releases.

#### Random number generator in the `testing`

namespace¶

The Python standard library random number generator was previously exposed
in the `testing`

namespace as `testing.rand`

. Using this generator is
not recommended and it will be removed in a future release. Use generators
from `numpy.random`

namespace instead.

#### Random integer generation on a closed interval¶

In accordance with the Python C API, which gives preference to the half-open
interval over the closed one, `np.random.random_integers`

is being
deprecated in favor of calling `np.random.randint`

, which has been
enhanced with the `dtype`

parameter as described under “New Features”.
However, `np.random.random_integers`

will not be removed anytime soon.

### FutureWarnings¶

#### Assigning to slices/views of `MaskedArray`

¶

Currently a slice of a masked array contains a view of the original data and a
copy-on-write view of the mask. Consequently, any changes to the slice’s mask
will result in a copy of the original mask being made and that new mask being
changed rather than the original. For example, if we make a slice of the
original like so, `view = original[:]`

, then modifications to the data in one
array will affect the data of the other but, because the mask will be copied
during assignment operations, changes to the mask will remain local. A similar
situation occurs when explicitly constructing a masked array using
`MaskedArray(data, mask)`

, the returned array will contain a view of `data`

but the mask will be a copy-on-write view of `mask`

.

In the future, these cases will be normalized so that the data and mask arrays
are treated the same way and modifications to either will propagate between
views. In 1.11, numpy will issue a `MaskedArrayFutureWarning`

warning
whenever user code modifies the mask of a view that in the future may cause
values to propagate back to the original. To silence these warnings and make
your code robust against the upcoming changes, you have two options: if you
want to keep the current behavior, call `masked_view.unshare_mask()`

before
modifying the mask. If you want to get the future behavior early, use
`masked_view._sharedmask = False`

. However, note that setting the
`_sharedmask`

attribute will break following explicit calls to
`masked_view.unshare_mask()`

.

## NumPy 1.10.4 Release Notes¶

This release is a bugfix source release motivated by a segfault regression. No windows binaries are provided for this release, as there appear to be bugs in the toolchain we use to generate those files. Hopefully that problem will be fixed for the next release. In the meantime, we suggest using one of the providers of windows binaries.

### Compatibility notes¶

- The trace function now calls the trace method on subclasses of ndarray, except for matrix, for which the current behavior is preserved. This is to help with the units package of AstroPy and hopefully will not cause problems.

### Issues Fixed¶

- gh-6922 BUG: numpy.recarray.sort segfaults on Windows.
- gh-6937 BUG: busday_offset does the wrong thing with modifiedpreceding roll.
- gh-6949 BUG: Type is lost when slicing a subclass of recarray.

### Merged PRs¶

The following PRs have been merged into 1.10.4. When the PR is a backport, the PR number for the original PR against master is listed.

- gh-6840 TST: Update travis testing script in 1.10.x
- gh-6843 BUG: Fix use of python 3 only FileNotFoundError in test_f2py.
- gh-6884 REL: Update pavement.py and setup.py to reflect current version.
- gh-6916 BUG: Fix test_f2py so it runs correctly in runtests.py.
- gh-6924 BUG: Fix segfault gh-6922.
- gh-6942 Fix datetime roll=’modifiedpreceding’ bug.
- gh-6943 DOC,BUG: Fix some latex generation problems.
- gh-6950 BUG trace is not subclass aware, np.trace(ma) != ma.trace().
- gh-6952 BUG recarray slices should preserve subclass.

## NumPy 1.10.3 Release Notes¶

N/A this release did not happen due to various screwups involving PyPi.

## NumPy 1.10.2 Release Notes¶

This release deals with a number of bugs that turned up in 1.10.1 and adds various build and release improvements.

Numpy 1.10.1 supports Python 2.6 - 2.7 and 3.2 - 3.5.

### Compatibility notes¶

#### Relaxed stride checking is no longer the default¶

There were back compatibility problems involving views changing the dtype of multidimensional Fortran arrays that need to be dealt with over a longer timeframe.

#### Fix swig bug in `numpy.i`

¶

Relaxed stride checking revealed a bug in `array_is_fortran(a)`

, that was
using PyArray_ISFORTRAN to check for Fortran contiguity instead of
PyArray_IS_F_CONTIGUOUS. You may want to regenerate swigged files using the
updated numpy.i

#### Deprecate views changing dimensions in fortran order¶

This deprecates assignment of a new descriptor to the dtype attribute of a non-C-contiguous array if it result in changing the shape. This effectively bars viewing a multidimensional Fortran array using a dtype that changes the element size along the first axis.

The reason for the deprecation is that, when relaxed strides checking is enabled, arrays that are both C and Fortran contiguous are always treated as C contiguous which breaks some code that depended the two being mutually exclusive for non-scalar arrays of ndim > 1. This deprecation prepares the way to always enable relaxed stride checking.

### Issues Fixed¶

- gh-6019 Masked array repr fails for structured array with multi-dimensional column.
- gh-6462 Median of empty array produces IndexError.
- gh-6467 Performance regression for record array access.
- gh-6468 numpy.interp uses ‘left’ value even when x[0]==xp[0].
- gh-6475 np.allclose returns a memmap when one of its arguments is a memmap.
- gh-6491 Error in broadcasting stride_tricks array.
- gh-6495 Unrecognized command line option ‘-ffpe-summary’ in gfortran.
- gh-6497 Failure of reduce operation on recarrays.
- gh-6498 Mention change in default casting rule in 1.10 release notes.
- gh-6530 The partition function errors out on empty input.
- gh-6532 numpy.inner return wrong inaccurate value sometimes.
- gh-6563 Intent(out) broken in recent versions of f2py.
- gh-6569 Cannot run tests after ‘python setup.py build_ext -i’
- gh-6572 Error in broadcasting stride_tricks array component.
- gh-6575 BUG: Split produces empty arrays with wrong number of dimensions
- gh-6590 Fortran Array problem in numpy 1.10.
- gh-6602 Random __all__ missing choice and dirichlet.
- gh-6611 ma.dot no longer always returns a masked array in 1.10.
- gh-6618 NPY_FORTRANORDER in make_fortran() in numpy.i
- gh-6636 Memory leak in nested dtypes in numpy.recarray
- gh-6641 Subsetting recarray by fields yields a structured array.
- gh-6667 ma.make_mask handles ma.nomask input incorrectly.
- gh-6675 Optimized blas detection broken in master and 1.10.
- gh-6678 Getting unexpected error from: X.dtype = complex (or Y = X.view(complex))
- gh-6718 f2py test fail in pip installed numpy-1.10.1 in virtualenv.
- gh-6719 Error compiling Cython file: Pythonic division not allowed without gil.
- gh-6771 Numpy.rec.fromarrays losing dtype metadata between versions 1.9.2 and 1.10.1
- gh-6781 The travis-ci script in maintenance/1.10.x needs fixing.
- gh-6807 Windows testing errors for 1.10.2

### Merged PRs¶

The following PRs have been merged into 1.10.2. When the PR is a backport, the PR number for the original PR against master is listed.

- gh-5773 MAINT: Hide testing helper tracebacks when using them with pytest.
- gh-6094 BUG: Fixed a bug with string representation of masked structured arrays.
- gh-6208 MAINT: Speedup field access by removing unneeded safety checks.
- gh-6460 BUG: Replacing the os.environ.clear by less invasive procedure.
- gh-6470 BUG: Fix AttributeError in numpy distutils.
- gh-6472 MAINT: Use Python 3.5 instead of 3.5-dev for travis 3.5 testing.
- gh-6474 REL: Update Paver script for sdist and auto-switch test warnings.
- gh-6478 BUG: Fix Intel compiler flags for OS X build.
- gh-6481 MAINT: LIBPATH with spaces is now supported Python 2.7+ and Win32.
- gh-6487 BUG: Allow nested use of parameters in definition of arrays in f2py.
- gh-6488 BUG: Extend common blocks rather than overwriting in f2py.
- gh-6499 DOC: Mention that default casting for inplace operations has changed.
- gh-6500 BUG: Recarrays viewed as subarrays don’t convert to np.record type.
- gh-6501 REL: Add “make upload” command for built docs, update “make dist”.
- gh-6526 BUG: Fix use of __doc__ in setup.py for -OO mode.
- gh-6527 BUG: Fix the IndexError when taking the median of an empty array.
- gh-6537 BUG: Make ma.atleast_* with scalar argument return arrays.
- gh-6538 BUG: Fix ma.masked_values does not shrink mask if requested.
- gh-6546 BUG: Fix inner product regression for non-contiguous arrays.
- gh-6553 BUG: Fix partition and argpartition error for empty input.
- gh-6556 BUG: Error in broadcast_arrays with as_strided array.
- gh-6558 MAINT: Minor update to “make upload” doc build command.
- gh-6562 BUG: Disable view safety checks in recarray.
- gh-6567 BUG: Revert some import * fixes in f2py.
- gh-6574 DOC: Release notes for Numpy 1.10.2.
- gh-6577 BUG: Fix for #6569, allowing build_ext –inplace
- gh-6579 MAINT: Fix mistake in doc upload rule.
- gh-6596 BUG: Fix swig for relaxed stride checking.
- gh-6606 DOC: Update 1.10.2 release notes.
- gh-6614 BUG: Add choice and dirichlet to numpy.random.__all__.
- gh-6621 BUG: Fix swig make_fortran function.
- gh-6628 BUG: Make allclose return python bool.
- gh-6642 BUG: Fix memleak in _convert_from_dict.
- gh-6643 ENH: make recarray.getitem return a recarray.
- gh-6653 BUG: Fix ma dot to always return masked array.
- gh-6668 BUG: ma.make_mask should always return nomask for nomask argument.
- gh-6686 BUG: Fix a bug in assert_string_equal.
- gh-6695 BUG: Fix removing tempdirs created during build.
- gh-6697 MAINT: Fix spurious semicolon in macro definition of PyArray_FROM_OT.
- gh-6698 TST: test np.rint bug for large integers.
- gh-6717 BUG: Readd fallback CBLAS detection on linux.
- gh-6721 BUG: Fix for #6719.
- gh-6726 BUG: Fix bugs exposed by relaxed stride rollback.
- gh-6757 BUG: link cblas library if cblas is detected.
- gh-6756 TST: only test f2py, not f2py2.7 etc, fixes #6718.
- gh-6747 DEP: Deprecate changing shape of non-C-contiguous array via descr.
- gh-6775 MAINT: Include from __future__ boilerplate in some files missing it.
- gh-6780 BUG: metadata is not copied to base_dtype.
- gh-6783 BUG: Fix travis ci testing for new google infrastructure.
- gh-6785 BUG: Quick and dirty fix for interp.
- gh-6813 TST,BUG: Make test_mvoid_multidim_print work for 32 bit systems.
- gh-6817 BUG: Disable 32-bit msvc9 compiler optimizations for npy_rint.
- gh-6819 TST: Fix test_mvoid_multidim_print failures on Python 2.x for Windows.

Initial support for mingwpy was reverted as it was causing problems for non-windows builds.

- gh-6536 BUG: Revert gh-5614 to fix non-windows build problems

A fix for np.lib.split was reverted because it resulted in “fixing” behavior that will be present in the Numpy 1.11 and that was already present in Numpy 1.9. See the discussion of the issue at gh-6575 for clarification.

- gh-6576 BUG: Revert gh-6376 to fix split behavior for empty arrays.

Relaxed stride checking was reverted. There were back compatibility problems involving views changing the dtype of multidimensional Fortran arrays that need to be dealt with over a longer timeframe.

- gh-6735 MAINT: Make no relaxed stride checking the default for 1.10.

### Notes¶

A bug in the Numpy 1.10.1 release resulted in exceptions being raised for
`RuntimeWarning`

and `DeprecationWarning`

in projects depending on Numpy.
That has been fixed.

## NumPy 1.10.1 Release Notes¶

This release deals with a few build problems that showed up in 1.10.0. Most users would not have seen these problems. The differences are:

- Compiling with msvc9 or msvc10 for 32 bit Windows now requires SSE2. This was the easiest fix for what looked to be some miscompiled code when SSE2 was not used. If you need to compile for 32 bit Windows systems without SSE2 support, mingw32 should still work.
- Make compiling with VS2008 python2.7 SDK easier
- Change Intel compiler options so that code will also be generated to support systems without SSE4.2.
- Some _config test functions needed an explicit integer return in order to avoid the openSUSE rpmlinter erring out.
- We ran into a problem with pipy not allowing reuse of filenames and a
resulting proliferation of
*.*.*.postN releases. Not only were the names getting out of hand, some packages were unable to work with the postN suffix.

Numpy 1.10.1 supports Python 2.6 - 2.7 and 3.2 - 3.5.

Commits:

45a3d84 DEP: Remove warning for *full* when dtype is set.
0c1a5df BLD: import setuptools to allow compile with VS2008 python2.7 sdk
04211c6 BUG: mask nan to 1 in ordered compare
826716f DOC: Document the reason msvc requires SSE2 on 32 bit platforms.
49fa187 BLD: enable SSE2 for 32-bit msvc 9 and 10 compilers
dcbc4cc MAINT: remove Wreturn-type warnings from config checks
d6564cb BLD: do not build exclusively for SSE4.2 processors
15cb66f BLD: do not build exclusively for SSE4.2 processors
c38bc08 DOC: fix var. reference in percentile docstring
78497f4 DOC: Sync 1.10.0-notes.rst in 1.10.x branch with master.

## NumPy 1.10.0 Release Notes¶

This release supports Python 2.6 - 2.7 and 3.2 - 3.5.

### Highlights¶

- numpy.distutils now supports parallel compilation via the –parallel/-j argument passed to setup.py build
- numpy.distutils now supports additional customization via site.cfg to control compilation parameters, i.e. runtime libraries, extra linking/compilation flags.
- Addition of
*np.linalg.multi_dot*: compute the dot product of two or more arrays in a single function call, while automatically selecting the fastest evaluation order. - The new function
*np.stack*provides a general interface for joining a sequence of arrays along a new axis, complementing*np.concatenate*for joining along an existing axis. - Addition of
*nanprod*to the set of nanfunctions. - Support for the ‘@’ operator in Python 3.5.

### Dropped Support¶

- The _dotblas module has been removed. CBLAS Support is now in Multiarray.
- The testcalcs.py file has been removed.
- The polytemplate.py file has been removed.
- npy_PyFile_Dup and npy_PyFile_DupClose have been removed from npy_3kcompat.h.
- splitcmdline has been removed from numpy/distutils/exec_command.py.
- try_run and get_output have been removed from numpy/distutils/command/config.py
- The a._format attribute is no longer supported for array printing.
- Keywords
`skiprows`

and`missing`

removed from np.genfromtxt. - Keyword
`old_behavior`

removed from np.correlate.

### Future Changes¶

- In array comparisons like
`arr1 == arr2`

, many corner cases involving strings or structured dtypes that used to return scalars now issue`FutureWarning`

or`DeprecationWarning`

, and in the future will be change to either perform elementwise comparisons or raise an error. - In
`np.lib.split`

an empty array in the result always had dimension`(0,)`

no matter the dimensions of the array being split. In Numpy 1.11 that behavior will be changed so that the dimensions will be preserved. A`FutureWarning`

for this change has been in place since Numpy 1.9 but, due to a bug, sometimes no warning was raised and the dimensions were already preserved. - The SafeEval class will be removed in Numpy 1.11.
- The alterdot and restoredot functions will be removed in Numpy 1.11.

See below for more details on these changes.

### Compatibility notes¶

#### Default casting rule change¶

Default casting for inplace operations has changed to `'same_kind'`

. For
instance, if n is an array of integers, and f is an array of floats, then
`n += f`

will result in a `TypeError`

, whereas in previous Numpy
versions the floats would be silently cast to ints. In the unlikely case
that the example code is not an actual bug, it can be updated in a backward
compatible way by rewriting it as `np.add(n, f, out=n, casting='unsafe')`

.
The old `'unsafe'`

default has been deprecated since Numpy 1.7.

#### numpy version string¶

The numpy version string for development builds has been changed from
`x.y.z.dev-githash`

to `x.y.z.dev0+githash`

(note the +) in order to comply
with PEP 440.

#### relaxed stride checking¶

NPY_RELAXED_STRIDE_CHECKING is now true by default.

UPDATE: In 1.10.2 the default value of NPY_RELAXED_STRIDE_CHECKING was changed to false for back compatibility reasons. More time is needed before it can be made the default. As part of the roadmap a deprecation of dimension changing views of f_contiguous not c_contiguous arrays was also added.

#### Concatenation of 1d arrays along any but `axis=0`

raises `IndexError`

¶

Using axis != 0 has raised a DeprecationWarning since NumPy 1.7, it now raises an error.

*np.ravel*, *np.diagonal* and *np.diag* now preserve subtypes¶

There was inconsistent behavior between *x.ravel()* and *np.ravel(x)*, as
well as between *x.diagonal()* and *np.diagonal(x)*, with the methods
preserving subtypes while the functions did not. This has been fixed and
the functions now behave like the methods, preserving subtypes except in
the case of matrices. Matrices are special cased for backward
compatibility and still return 1-D arrays as before. If you need to
preserve the matrix subtype, use the methods instead of the functions.

*rollaxis* and *swapaxes* always return a view¶

Previously, a view was returned except when no change was made in the order of the axes, in which case the input array was returned. A view is now returned in all cases.

*nonzero* now returns base ndarrays¶

Previously, an inconsistency existed between 1-D inputs (returning a
base ndarray) and higher dimensional ones (which preserved subclasses).
Behavior has been unified, and the return will now be a base ndarray.
Subclasses can still override this behavior by providing their own
*nonzero* method.

#### C API¶

The changes to *swapaxes* also apply to the *PyArray_SwapAxes* C function,
which now returns a view in all cases.

The changes to *nonzero* also apply to the *PyArray_Nonzero* C function,
which now returns a base ndarray in all cases.

The dtype structure (PyArray_Descr) has a new member at the end to cache its hash value. This shouldn’t affect any well-written applications.

The change to the concatenation function DeprecationWarning also affects PyArray_ConcatenateArrays,

#### recarray field return types¶

Previously the returned types for recarray fields accessed by attribute and by index were inconsistent, and fields of string type were returned as chararrays. Now, fields accessed by either attribute or indexing will return an ndarray for fields of non-structured type, and a recarray for fields of structured type. Notably, this affect recarrays containing strings with whitespace, as trailing whitespace is trimmed from chararrays but kept in ndarrays of string type. Also, the dtype.type of nested structured fields is now inherited.

#### recarray views¶

Viewing an ndarray as a recarray now automatically converts the dtype to np.record. See new record array documentation. Additionally, viewing a recarray with a non-structured dtype no longer converts the result’s type to ndarray - the result will remain a recarray.

#### ‘out’ keyword argument of ufuncs now accepts tuples of arrays¶

When using the ‘out’ keyword argument of a ufunc, a tuple of arrays, one per
ufunc output, can be provided. For ufuncs with a single output a single array
is also a valid ‘out’ keyword argument. Previously a single array could be
provided in the ‘out’ keyword argument, and it would be used as the first
output for ufuncs with multiple outputs, is deprecated, and will result in a
*DeprecationWarning* now and an error in the future.

#### byte-array indices now raises an IndexError¶

Indexing an ndarray using a byte-string in Python 3 now raises an IndexError instead of a ValueError.

#### Masked arrays containing objects with arrays¶

For such (rare) masked arrays, getting a single masked item no longer returns a corrupted masked array, but a fully masked version of the item.

#### Median warns and returns nan when invalid values are encountered¶

Similar to mean, median and percentile now emits a Runtime warning and
returns *NaN* in slices where a *NaN* is present.
To compute the median or percentile while ignoring invalid values use the
new *nanmedian* or *nanpercentile* functions.

#### Functions available from numpy.ma.testutils have changed¶

All functions from numpy.testing were once available from numpy.ma.testutils but not all of them were redefined to work with masked arrays. Most of those functions have now been removed from numpy.ma.testutils with a small subset retained in order to preserve backward compatibility. In the long run this should help avoid mistaken use of the wrong functions, but it may cause import problems for some.

### New Features¶

#### Reading extra flags from site.cfg¶

Previously customization of compilation of dependency libraries and numpy
itself was only accomblishable via code changes in the distutils package.
Now numpy.distutils reads in the following extra flags from each group of the
*site.cfg*:

`runtime_library_dirs/rpath`

, sets runtime library directories to override`LD_LIBRARY_PATH`

`extra_compile_args`

, add extra flags to the compilation of sources`extra_link_args`

, add extra flags when linking libraries

This should, at least partially, complete user customization.

*np.cbrt* to compute cube root for real floats¶

*np.cbrt* wraps the C99 cube root function *cbrt*.
Compared to *np.power(x, 1./3.)* it is well defined for negative real floats
and a bit faster.

#### numpy.distutils now allows parallel compilation¶

By passing *–parallel=n* or *-j n* to *setup.py build* the compilation of
extensions is now performed in *n* parallel processes.
The parallelization is limited to files within one extension so projects using
Cython will not profit because it builds extensions from single files.

*genfromtxt* has a new `max_rows`

argument¶

A `max_rows`

argument has been added to *genfromtxt* to limit the
number of rows read in a single call. Using this functionality, it is
possible to read in multiple arrays stored in a single file by making
repeated calls to the function.

#### New function *np.broadcast_to* for invoking array broadcasting¶

*np.broadcast_to* manually broadcasts an array to a given shape according to
numpy’s broadcasting rules. The functionality is similar to broadcast_arrays,
which in fact has been rewritten to use broadcast_to internally, but only a
single array is necessary.

#### New context manager *clear_and_catch_warnings* for testing warnings¶

When Python emits a warning, it records that this warning has been emitted in
the module that caused the warning, in a module attribute
`__warningregistry__`

. Once this has happened, it is not possible to emit
the warning again, unless you clear the relevant entry in
`__warningregistry__`

. This makes is hard and fragile to test warnings,
because if your test comes after another that has already caused the warning,
you will not be able to emit the warning or test it. The context manager
`clear_and_catch_warnings`

clears warnings from the module registry on entry
and resets them on exit, meaning that warnings can be re-raised.

*cov* has new `fweights`

and `aweights`

arguments¶

The `fweights`

and `aweights`

arguments add new functionality to
covariance calculations by applying two types of weighting to observation
vectors. An array of `fweights`

indicates the number of repeats of each
observation vector, and an array of `aweights`

provides their relative
importance or probability.

#### Support for the ‘@’ operator in Python 3.5+¶

Python 3.5 adds support for a matrix multiplication operator ‘@’ proposed
in PEP465. Preliminary support for that has been implemented, and an
equivalent function `matmul`

has also been added for testing purposes and
use in earlier Python versions. The function is preliminary and the order
and number of its optional arguments can be expected to change.

#### New argument `norm`

to fft functions¶

The default normalization has the direct transforms unscaled and the inverse
transforms are scaled by . It is possible to obtain unitary
transforms by setting the keyword argument `norm`

to `"ortho"`

(default is
*None*) so that both direct and inverse transforms will be scaled by
.

### Improvements¶

*np.digitize* using binary search¶

*np.digitize* is now implemented in terms of *np.searchsorted*. This means
that a binary search is used to bin the values, which scales much better
for larger number of bins than the previous linear search. It also removes
the requirement for the input array to be 1-dimensional.

*np.poly* now casts integer inputs to float¶

*np.poly* will now cast 1-dimensional input arrays of integer type to double
precision floating point, to prevent integer overflow when computing the monic
polynomial. It is still possible to obtain higher precision results by
passing in an array of object type, filled e.g. with Python ints.

*np.interp* can now be used with periodic functions¶

*np.interp* now has a new parameter *period* that supplies the period of the
input data *xp*. In such case, the input data is properly normalized to the
given period and one end point is added to each extremity of *xp* in order to
close the previous and the next period cycles, resulting in the correct
interpolation behavior.

*np.pad* supports more input types for `pad_width`

and `constant_values`

¶

`constant_values`

parameters now accepts NumPy arrays and float values.
NumPy arrays are supported as input for `pad_width`

, and an exception is
raised if its values are not of integral type.

*np.argmax* and *np.argmin* now support an `out`

argument¶

The `out`

parameter was added to *np.argmax* and *np.argmin* for consistency
with *ndarray.argmax* and *ndarray.argmin*. The new parameter behaves exactly
as it does in those methods.

#### More system C99 complex functions detected and used¶

All of the functions `in complex.h`

are now detected. There are new
fallback implementations of the following functions.

- npy_ctan,
- npy_cacos, npy_casin, npy_catan
- npy_ccosh, npy_csinh, npy_ctanh,
- npy_cacosh, npy_casinh, npy_catanh

As a result of these improvements, there will be some small changes in returned values, especially for corner cases.

*np.loadtxt* support for the strings produced by the `float.hex`

method¶

The strings produced by `float.hex`

look like `0x1.921fb54442d18p+1`

,
so this is not the hex used to represent unsigned integer types.

*np.isclose* properly handles minimal values of integer dtypes¶

In order to properly handle minimal values of integer types, *np.isclose* will
now cast to the float dtype during comparisons. This aligns its behavior with
what was provided by *np.allclose*.

*np.allclose* uses *np.isclose* internally.¶

*np.allclose* now uses *np.isclose* internally and inherits the ability to
compare NaNs as equal by setting `equal_nan=True`

. Subclasses, such as
*np.ma.MaskedArray*, are also preserved now.

*np.genfromtxt* now handles large integers correctly¶

*np.genfromtxt* now correctly handles integers larger than `2**31-1`

on
32-bit systems and larger than `2**63-1`

on 64-bit systems (it previously
crashed with an `OverflowError`

in these cases). Integers larger than
`2**63-1`

are converted to floating-point values.

*np.load*, *np.save* have pickle backward compatibility flags¶

The functions *np.load* and *np.save* have additional keyword
arguments for controlling backward compatibility of pickled Python
objects. This enables Numpy on Python 3 to load npy files containing
object arrays that were generated on Python 2.

#### MaskedArray support for more complicated base classes¶

Built-in assumptions that the baseclass behaved like a plain array are being
removed. In particular, setting and getting elements and ranges will respect
baseclass overrides of `__setitem__`

and `__getitem__`

, and arithmetic
will respect overrides of `__add__`

, `__sub__`

, etc.

### Changes¶

#### dotblas functionality moved to multiarray¶

The cblas versions of dot, inner, and vdot have been integrated into the multiarray module. In particular, vdot is now a multiarray function, which it was not before.

#### stricter check of gufunc signature compliance¶

Inputs to generalized universal functions are now more strictly checked against the function’s signature: all core dimensions are now required to be present in input arrays; core dimensions with the same label must have the exact same size; and output core dimension’s must be specified, either by a same label input core dimension or by a passed-in output array.

#### views returned from *np.einsum* are writeable¶

Views returned by *np.einsum* will now be writeable whenever the input
array is writeable.

*np.argmin* skips NaT values¶

*np.argmin* now skips NaT values in datetime64 and timedelta64 arrays,
making it consistent with *np.min*, *np.argmax* and *np.max*.

### Deprecations¶

#### Array comparisons involving strings or structured dtypes¶

Normally, comparison operations on arrays perform elementwise comparisons and return arrays of booleans. But in some corner cases, especially involving strings are structured dtypes, NumPy has historically returned a scalar instead. For example:

```
### Current behaviour
np.arange(2) == "foo"
# -> False
np.arange(2) < "foo"
# -> True on Python 2, error on Python 3
np.ones(2, dtype="i4,i4") == np.ones(2, dtype="i4,i4,i4")
# -> False
```

Continuing work started in 1.9, in 1.10 these comparisons will now
raise `FutureWarning`

or `DeprecationWarning`

, and in the future
they will be modified to behave more consistently with other
comparison operations, e.g.:

```
### Future behaviour
np.arange(2) == "foo"
# -> array([False, False])
np.arange(2) < "foo"
# -> error, strings and numbers are not orderable
np.ones(2, dtype="i4,i4") == np.ones(2, dtype="i4,i4,i4")
# -> [False, False]
```

#### SafeEval¶

The SafeEval class in numpy/lib/utils.py is deprecated and will be removed in the next release.

#### alterdot, restoredot¶

The alterdot and restoredot functions no longer do anything, and are deprecated.

#### pkgload, PackageLoader¶

These ways of loading packages are now deprecated.

#### bias, ddof arguments to corrcoef¶

The values for the `bias`

and `ddof`

arguments to the `corrcoef`

function canceled in the division implied by the correlation coefficient and
so had no effect on the returned values.

We now deprecate these arguments to `corrcoef`

and the masked array version
`ma.corrcoef`

.

Because we are deprecating the `bias`

argument to `ma.corrcoef`

, we also
deprecate the use of the `allow_masked`

argument as a positional argument,
as its position will change with the removal of `bias`

. `allow_masked`

will in due course become a keyword-only argument.

#### dtype string representation changes¶

Since 1.6, creating a dtype object from its string representation, e.g.
`'f4'`

, would issue a deprecation warning if the size did not correspond
to an existing type, and default to creating a dtype of the default size
for the type. Starting with this release, this will now raise a `TypeError`

.

The only exception is object dtypes, where both `'O4'`

and `'O8'`

will
still issue a deprecation warning. This platform-dependent representation
will raise an error in the next release.

In preparation for this upcoming change, the string representation of an
object dtype, i.e. `np.dtype(object).str`

, no longer includes the item
size, i.e. will return `'|O'`

instead of `'|O4'`

or `'|O8'`

as
before.

## NumPy 1.9.2 Release Notes¶

This is a bugfix only release in the 1.9.x series.

### Issues fixed¶

- #5316: fix too large dtype alignment of strings and complex types
- #5424: fix ma.median when used on ndarrays
- #5481: Fix astype for structured array fields of different byte order
- #5354: fix segfault when clipping complex arrays
- #5524: allow np.argpartition on non ndarrays
- #5612: Fixes ndarray.fill to accept full range of uint64
- #5155: Fix loadtxt with comments=None and a string None data
- #4476: Masked array view fails if structured dtype has datetime component
- #5388: Make RandomState.set_state and RandomState.get_state threadsafe
- #5390: make seed, randint and shuffle threadsafe
- #5374: Fixed incorrect assert_array_almost_equal_nulp documentation
- #5393: Add support for ATLAS > 3.9.33.
- #5313: PyArray_AsCArray caused segfault for 3d arrays
- #5492: handle out of memory in rfftf
- #4181: fix a few bugs in the random.pareto docstring
- #5359: minor changes to linspace docstring
- #4723: fix a compile issues on AIX

## NumPy 1.9.1 Release Notes¶

This is a bugfix only release in the 1.9.x series.

### Issues fixed¶

- gh-5184: restore linear edge behaviour of gradient to as it was in < 1.9.
The second order behaviour is available via the
*edge_order*keyword - gh-4007: workaround Accelerate sgemv crash on OSX 10.9
- gh-5100: restore object dtype inference from iterable objects without
*len()* - gh-5163: avoid gcc-4.1.2 (red hat 5) miscompilation causing a crash
- gh-5138: fix nanmedian on arrays containing inf
- gh-5240: fix not returning out array from ufuncs with subok=False set
- gh-5203: copy inherited masks in MaskedArray.__array_finalize__
- gh-2317: genfromtxt did not handle filling_values=0 correctly
- gh-5067: restore api of npy_PyFile_DupClose in python2
- gh-5063: cannot convert invalid sequence index to tuple
- gh-5082: Segmentation fault with argmin() on unicode arrays
- gh-5095: don’t propagate subtypes from np.where
- gh-5104: np.inner segfaults with SciPy’s sparse matrices
- gh-5251: Issue with fromarrays not using correct format for unicode arrays
- gh-5136: Import dummy_threading if importing threading fails
- gh-5148: Make numpy import when run with Python flag ‘-OO’
- gh-5147: Einsum double contraction in particular order causes ValueError
- gh-479: Make f2py work with intent(in out)
- gh-5170: Make python2 .npy files readable in python3
- gh-5027: Use ‘ll’ as the default length specifier for long long
- gh-4896: fix build error with MSVC 2013 caused by C99 complex support
- gh-4465: Make PyArray_PutTo respect writeable flag
- gh-5225: fix crash when using arange on datetime without dtype set
- gh-5231: fix build in c99 mode

## NumPy 1.9.0 Release Notes¶

This release supports Python 2.6 - 2.7 and 3.2 - 3.4.

### Highlights¶

- Numerous performance improvements in various areas, most notably indexing and operations on small arrays are significantly faster. Indexing operations now also release the GIL.
- Addition of
*nanmedian*and*nanpercentile*rounds out the nanfunction set.

### Dropped Support¶

- The oldnumeric and numarray modules have been removed.
- The doc/pyrex and doc/cython directories have been removed.
- The doc/numpybook directory has been removed.
- The numpy/testing/numpytest.py file has been removed together with the importall function it contained.

### Future Changes¶

- The numpy/polynomial/polytemplate.py file will be removed in NumPy 1.10.0.
- Default casting for inplace operations will change to ‘same_kind’ in Numpy 1.10.0. This will certainly break some code that is currently ignoring the warning.
- Relaxed stride checking will be the default in 1.10.0
- String version checks will break because, e.g., ‘1.9’ > ‘1.10’ is True. A NumpyVersion class has been added that can be used for such comparisons.
- The diagonal and diag functions will return writeable views in 1.10.0
- The
*S*and/or*a*dtypes may be changed to represent Python strings instead of bytes, in Python 3 these two types are very different.

### Compatibility notes¶

#### The diagonal and diag functions return readonly views.¶

In NumPy 1.8, the diagonal and diag functions returned readonly copies, in NumPy 1.9 they return readonly views, and in 1.10 they will return writeable views.

#### Special scalar float values don’t cause upcast to double anymore¶

In previous numpy versions operations involving floating point scalars
containing special values `NaN`

, `Inf`

and `-Inf`

caused the result
type to be at least `float64`

. As the special values can be represented
in the smallest available floating point type, the upcast is not performed
anymore.

For example the dtype of:

`np.array([1.], dtype=np.float32) * float('nan')`

now remains `float32`

instead of being cast to `float64`

.
Operations involving non-special values have not been changed.

#### Percentile output changes¶

If given more than one percentile to compute numpy.percentile returns an
array instead of a list. A single percentile still returns a scalar. The
array is equivalent to converting the list returned in older versions
to an array via `np.array`

.

If the `overwrite_input`

option is used the input is only partially
instead of fully sorted.

#### ndarray.tofile exception type¶

All `tofile`

exceptions are now `IOError`

, some were previously
`ValueError`

.

#### Invalid fill value exceptions¶

Two changes to numpy.ma.core._check_fill_value:

- When the fill value is a string and the array type is not one of ‘OSUV’, TypeError is raised instead of the default fill value being used.
- When the fill value overflows the array type, TypeError is raised instead of OverflowError.

#### Polynomial Classes no longer derived from PolyBase¶

This may cause problems with folks who depended on the polynomial classes being derived from PolyBase. They are now all derived from the abstract base class ABCPolyBase. Strictly speaking, there should be a deprecation involved, but no external code making use of the old baseclass could be found.

#### Using numpy.random.binomial may change the RNG state vs. numpy < 1.9¶

A bug in one of the algorithms to generate a binomial random variate has been fixed. This change will likely alter the number of random draws performed, and hence the sequence location will be different after a call to distribution.c::rk_binomial_btpe. Any tests which rely on the RNG being in a known state should be checked and/or updated as a result.

#### Random seed enforced to be a 32 bit unsigned integer¶

`np.random.seed`

and `np.random.RandomState`

now throw a `ValueError`

if the seed cannot safely be converted to 32 bit unsigned integers.
Applications that now fail can be fixed by masking the higher 32 bit values to
zero: `seed = seed & 0xFFFFFFFF`

. This is what is done silently in older
versions so the random stream remains the same.

#### Argmin and argmax out argument¶

The `out`

argument to `np.argmin`

and `np.argmax`

and their
equivalent C-API functions is now checked to match the desired output shape
exactly. If the check fails a `ValueError`

instead of `TypeError`

is
raised.

#### Einsum¶

Remove unnecessary broadcasting notation restrictions.
`np.einsum('ijk,j->ijk', A, B)`

can also be written as
`np.einsum('ij...,j->ij...', A, B)`

(ellipsis is no longer required on ‘j’)

#### Indexing¶

The NumPy indexing has seen a complete rewrite in this version. This makes most advanced integer indexing operations much faster and should have no other implications. However some subtle changes and deprecations were introduced in advanced indexing operations:

- Boolean indexing into scalar arrays will always return a new 1-d array.
This means that
`array(1)[array(True)]`

gives`array([1])`

and not the original array. - Advanced indexing into one dimensional arrays used to have
(undocumented) special handling regarding repeating the value array in
assignments when the shape of the value array was too small or did not
match. Code using this will raise an error. For compatibility you can
use
`arr.flat[index] = values`

, which uses the old code branch. (for example`a = np.ones(10); a[np.arange(10)] = [1, 2, 3]`

) - The iteration order over advanced indexes used to be always C-order.
In NumPy 1.9. the iteration order adapts to the inputs and is not
guaranteed (with the exception of a
*single*advanced index which is never reversed for compatibility reasons). This means that the result is undefined if multiple values are assigned to the same element. An example for this is`arr[[0, 0], [1, 1]] = [1, 2]`

, which may set`arr[0, 1]`

to either 1 or 2. - Equivalent to the iteration order, the memory layout of the advanced indexing result is adapted for faster indexing and cannot be predicted.
- All indexing operations return a view or a copy. No indexing operation
will return the original array object. (For example
`arr[...]`

) - In the future Boolean array-likes (such as lists of python bools) will
always be treated as Boolean indexes and Boolean scalars (including
python
`True`

) will be a legal*boolean*index. At this time, this is already the case for scalar arrays to allow the general`positive = a[a > 0]`

to work when`a`

is zero dimensional. - In NumPy 1.8 it was possible to use
`array(True)`

and`array(False)`

equivalent to 1 and 0 if the result of the operation was a scalar. This will raise an error in NumPy 1.9 and, as noted above, treated as a boolean index in the future. - All non-integer array-likes are deprecated, object arrays of custom integer like objects may have to be cast explicitly.
- The error reporting for advanced indexing is more informative, however
the error type has changed in some cases. (Broadcasting errors of
indexing arrays are reported as
`IndexError`

) - Indexing with more then one ellipsis (
`...`

) is deprecated.

#### Non-integer reduction axis indexes are deprecated¶

Non-integer axis indexes to reduction ufuncs like *add.reduce* or *sum* are
deprecated.

`promote_types`

and string dtype¶

`promote_types`

function now returns a valid string length when given an
integer or float dtype as one argument and a string dtype as another
argument. Previously it always returned the input string dtype, even if it
wasn’t long enough to store the max integer/float value converted to a
string.

`can_cast`

and string dtype¶

`can_cast`

function now returns False in “safe” casting mode for
integer/float dtype and string dtype if the string dtype length is not long
enough to store the max integer/float value converted to a string.
Previously `can_cast`

in “safe” mode returned True for integer/float
dtype and a string dtype of any length.

#### astype and string dtype¶

The `astype`

method now returns an error if the string dtype to cast to
is not long enough in “safe” casting mode to hold the max value of
integer/float array that is being casted. Previously the casting was
allowed even if the result was truncated.

*npyio.recfromcsv* keyword arguments change¶

*npyio.recfromcsv* no longer accepts the undocumented *update* keyword,
which used to override the *dtype* keyword.

#### The `doc/swig`

directory moved¶

The `doc/swig`

directory has been moved to `tools/swig`

.

#### The `npy_3kcompat.h`

header changed¶

The unused `simple_capsule_dtor`

function has been removed from
`npy_3kcompat.h`

. Note that this header is not meant to be used outside
of numpy; other projects should be using their own copy of this file when
needed.

#### Negative indices in C-Api `sq_item`

and `sq_ass_item`

sequence methods¶

When directly accessing the `sq_item`

or `sq_ass_item`

PyObject slots
for item getting, negative indices will not be supported anymore.
`PySequence_GetItem`

and `PySequence_SetItem`

however fix negative
indices so that they can be used there.

#### NDIter¶

When `NpyIter_RemoveAxis`

is now called, the iterator range will be reset.

When a multi index is being tracked and an iterator is not buffered, it is
possible to use `NpyIter_RemoveAxis`

. In this case an iterator can shrink
in size. Because the total size of an iterator is limited, the iterator
may be too large before these calls. In this case its size will be set to `-1`

and an error issued not at construction time but when removing the multi
index, setting the iterator range, or getting the next function.

This has no effect on currently working code, but highlights the necessity of checking for an error return if these conditions can occur. In most cases the arrays being iterated are as large as the iterator so that such a problem cannot occur.

This change was already applied to the 1.8.1 release.

`zeros_like`

for string dtypes now returns empty strings¶

To match the *zeros* function *zeros_like* now returns an array initialized
with empty strings instead of an array filled with *‘0’*.

### New Features¶

#### Percentile supports more interpolation options¶

`np.percentile`

now has the interpolation keyword argument to specify in
which way points should be interpolated if the percentiles fall between two
values. See the documentation for the available options.

#### Generalized axis support for median and percentile¶

`np.median`

and `np.percentile`

now support generalized axis arguments like
ufunc reductions do since 1.7. One can now say axis=(index, index) to pick a
list of axes for the reduction. The `keepdims`

keyword argument was also
added to allow convenient broadcasting to arrays of the original shape.

#### Dtype parameter added to `np.linspace`

and `np.logspace`

¶

The returned data type from the `linspace`

and `logspace`

functions can
now be specified using the dtype parameter.

#### More general `np.triu`

and `np.tril`

broadcasting¶

For arrays with `ndim`

exceeding 2, these functions will now apply to the
final two axes instead of raising an exception.

`tobytes`

alias for `tostring`

method¶

`ndarray.tobytes`

and `MaskedArray.tobytes`

have been added as aliases
for `tostring`

which exports arrays as `bytes`

. This is more consistent
in Python 3 where `str`

and `bytes`

are not the same.

#### Build system¶

Added experimental support for the ppc64le and OpenRISC architecture.

#### Compatibility to python `numbers`

module¶

All numerical numpy types are now registered with the type hierarchy in
the python `numbers`

module.

`increasing`

parameter added to `np.vander`

¶

The ordering of the columns of the Vandermonde matrix can be specified with this new boolean argument.

`unique_counts`

parameter added to `np.unique`

¶

The number of times each unique item comes up in the input can now be obtained as an optional return value.

#### Support for median and percentile in nanfunctions¶

The `np.nanmedian`

and `np.nanpercentile`

functions behave like
the median and percentile functions except that NaNs are ignored.

#### NumpyVersion class added¶

The class may be imported from numpy.lib and can be used for version comparison when the numpy version goes to 1.10.devel. For example:

```
>>> from numpy.lib import NumpyVersion
>>> if NumpyVersion(np.__version__) < '1.10.0'):
... print('Wow, that is an old NumPy version!')
```

#### Allow saving arrays with large number of named columns¶

The numpy storage format 1.0 only allowed the array header to have a total size
of 65535 bytes. This can be exceeded by structured arrays with a large number
of columns. A new format 2.0 has been added which extends the header size to 4
GiB. *np.save* will automatically save in 2.0 format if the data requires it,
else it will always use the more compatible 1.0 format.

#### Full broadcasting support for `np.cross`

¶

`np.cross`

now properly broadcasts its two input arrays, even if they
have different number of dimensions. In earlier versions this would result
in either an error being raised, or wrong results computed.

### Improvements¶

#### Better numerical stability for sum in some cases¶

Pairwise summation is now used in the sum method, but only along the fast axis and for groups of the values <= 8192 in length. This should also improve the accuracy of var and std in some common cases.

#### Percentile implemented in terms of `np.partition`

¶

`np.percentile`

has been implemented in terms of `np.partition`

which
only partially sorts the data via a selection algorithm. This improves the
time complexity from `O(nlog(n))`

to `O(n)`

.

#### Performance improvement for `np.array`

¶

The performance of converting lists containing arrays to arrays using
`np.array`

has been improved. It is now equivalent in speed to
`np.vstack(list)`

.

#### Performance improvement for `np.searchsorted`

¶

For the built-in numeric types, `np.searchsorted`

no longer relies on the
data type’s `compare`

function to perform the search, but is now
implemented by type specific functions. Depending on the size of the
inputs, this can result in performance improvements over 2x.

#### Optional reduced verbosity for np.distutils¶

Set `numpy.distutils.system_info.system_info.verbosity = 0`

and then
calls to `numpy.distutils.system_info.get_info('blas_opt')`

will not
print anything on the output. This is mostly for other packages using
numpy.distutils.

#### Covariance check in `np.random.multivariate_normal`

¶

A `RuntimeWarning`

warning is raised when the covariance matrix is not
positive-semidefinite.

#### Polynomial Classes no longer template based¶

The polynomial classes have been refactored to use an abstract base class rather than a template in order to implement a common interface. This makes importing the polynomial package faster as the classes do not need to be compiled on import.

#### More GIL releases¶

Several more functions now release the Global Interpreter Lock allowing more
efficient parallelization using the `threading`

module. Most notably the GIL is
now released for fancy indexing, `np.where`

and the `random`

module now
uses a per-state lock instead of the GIL.

#### MaskedArray support for more complicated base classes¶

Built-in assumptions that the baseclass behaved like a plain array are being
removed. In particalur, `repr`

and `str`

should now work more reliably.

#### C-API¶

### Deprecations¶

#### Non-integer scalars for sequence repetition¶

Using non-integer numpy scalars to repeat python sequences is deprecated.
For example `np.float_(2) * [1]`

will be an error in the future.

`select`

input deprecations¶

The integer and empty input to `select`

is deprecated. In the future only
boolean arrays will be valid conditions and an empty `condlist`

will be
considered an input error instead of returning the default.

`rank`

function¶

The `rank`

function has been deprecated to avoid confusion with
`numpy.linalg.matrix_rank`

.

#### Object array equality comparisons¶

In the future object array comparisons both *==* and *np.equal* will not
make use of identity checks anymore. For example:

```
>>> a = np.array([np.array([1, 2, 3]), 1])
>>> b = np.array([np.array([1, 2, 3]), 1])
>>> a == b
```

will consistently return False (and in the future an error) even if the array
in *a* and *b* was the same object.

The equality operator *==* will in the future raise errors like *np.equal*
if broadcasting or element comparisons, etc. fails.

Comparison with *arr == None* will in the future do an elementwise comparison
instead of just returning False. Code should be using *arr is None*.

All of these changes will give Deprecation- or FutureWarnings at this time.

#### C-API¶

The utility function npy_PyFile_Dup and npy_PyFile_DupClose are broken by the internal buffering python 3 applies to its file objects. To fix this two new functions npy_PyFile_Dup2 and npy_PyFile_DupClose2 are declared in npy_3kcompat.h and the old functions are deprecated. Due to the fragile nature of these functions it is recommended to instead use the python API when possible.

This change was already applied to the 1.8.1 release.

## NumPy 1.8.2 Release Notes¶

This is a bugfix only release in the 1.8.x series.

### Issues fixed¶

- gh-4836: partition produces wrong results for multiple selections in equal ranges
- gh-4656: Make fftpack._raw_fft threadsafe
- gh-4628: incorrect argument order to _copyto in in np.nanmax, np.nanmin
- gh-4642: Hold GIL for converting dtypes types with fields
- gh-4733: fix np.linalg.svd(b, compute_uv=False)
- gh-4853: avoid unaligned simd load on reductions on i386
- gh-4722: Fix seg fault converting empty string to object
- gh-4613: Fix lack of NULL check in array_richcompare
- gh-4774: avoid unaligned access for strided byteswap
- gh-650: Prevent division by zero when creating arrays from some buffers
- gh-4602: ifort has issues with optimization flag O2, use O1

## NumPy 1.8.1 Release Notes¶

This is a bugfix only release in the 1.8.x series.

### Issues fixed¶

- gh-4276: Fix mean, var, std methods for object arrays
- gh-4262: remove insecure mktemp usage
- gh-2385: absolute(complex(inf)) raises invalid warning in python3
- gh-4024: Sequence assignment doesn’t raise exception on shape mismatch
- gh-4027: Fix chunked reading of strings longer than BUFFERSIZE
- gh-4109: Fix object scalar return type of 0-d array indices
- gh-4018: fix missing check for memory allocation failure in ufuncs
- gh-4156: high order linalg.norm discards imaginary elements of complex arrays
- gh-4144: linalg: norm fails on longdouble, signed int
- gh-4094: fix NaT handling in _strided_to_strided_string_to_datetime
- gh-4051: fix uninitialized use in _strided_to_strided_string_to_datetime
- gh-4093: Loading compressed .npz file fails under Python 2.6.6
- gh-4138: segfault with non-native endian memoryview in python 3.4
- gh-4123: Fix missing NULL check in lexsort
- gh-4170: fix native-only long long check in memoryviews
- gh-4187: Fix large file support on 32 bit
- gh-4152: fromfile: ensure file handle positions are in sync in python3
- gh-4176: clang compatibility: Typos in conversion_utils
- gh-4223: Fetching a non-integer item caused array return
- gh-4197: fix minor memory leak in memoryview failure case
- gh-4206: fix build with single-threaded python
- gh-4220: add versionadded:: 1.8.0 to ufunc.at docstring
- gh-4267: improve handling of memory allocation failure
- gh-4267: fix use of capi without gil in ufunc.at
- gh-4261: Detect vendor versions of GNU Compilers
- gh-4253: IRR was returning nan instead of valid negative answer
- gh-4254: fix unnecessary byte order flag change for byte arrays
- gh-3263: numpy.random.shuffle clobbers mask of a MaskedArray
- gh-4270: np.random.shuffle not work with flexible dtypes
- gh-3173: Segmentation fault when ‘size’ argument to random.multinomial
- gh-2799: allow using unique with lists of complex
- gh-3504: fix linspace truncation for integer array scalar
- gh-4191: get_info(‘openblas’) does not read libraries key
- gh-3348: Access violation in _descriptor_from_pep3118_format
- gh-3175: segmentation fault with numpy.array() from bytearray
- gh-4266: histogramdd - wrong result for entries very close to last boundary
- gh-4408: Fix stride_stricks.as_strided function for object arrays
- gh-4225: fix log1p and exmp1 return for np.inf on windows compiler builds
- gh-4359: Fix infinite recursion in str.format of flex arrays
- gh-4145: Incorrect shape of broadcast result with the exponent operator
- gh-4483: Fix commutativity of {dot,multiply,inner}(scalar, matrix_of_objs)
- gh-4466: Delay npyiter size check when size may change
- gh-4485: Buffered stride was erroneously marked fixed
- gh-4354: byte_bounds fails with datetime dtypes
- gh-4486: segfault/error converting from/to high-precision datetime64 objects
- gh-4428: einsum(None, None, None, None) causes segfault
- gh-4134: uninitialized use for for size 1 object reductions

### Changes¶

#### NDIter¶

When `NpyIter_RemoveAxis`

is now called, the iterator range will be reset.

When a multi index is being tracked and an iterator is not buffered, it is
possible to use `NpyIter_RemoveAxis`

. In this case an iterator can shrink
in size. Because the total size of an iterator is limited, the iterator
may be too large before these calls. In this case its size will be set to `-1`

and an error issued not at construction time but when removing the multi
index, setting the iterator range, or getting the next function.

This has no effect on currently working code, but highlights the necessity of checking for an error return if these conditions can occur. In most cases the arrays being iterated are as large as the iterator so that such a problem cannot occur.

#### Optional reduced verbosity for np.distutils¶

Set `numpy.distutils.system_info.system_info.verbosity = 0`

and then
calls to `numpy.distutils.system_info.get_info('blas_opt')`

will not
print anything on the output. This is mostly for other packages using
numpy.distutils.

### Deprecations¶

#### C-API¶

The utility function npy_PyFile_Dup and npy_PyFile_DupClose are broken by the internal buffering python 3 applies to its file objects. To fix this two new functions npy_PyFile_Dup2 and npy_PyFile_DupClose2 are declared in npy_3kcompat.h and the old functions are deprecated. Due to the fragile nature of these functions it is recommended to instead use the python API when possible.

## NumPy 1.8.0 Release Notes¶

This release supports Python 2.6 -2.7 and 3.2 - 3.3.

### Highlights¶

- New, no 2to3, Python 2 and Python 3 are supported by a common code base.
- New, gufuncs for linear algebra, enabling operations on stacked arrays.
- New, inplace fancy indexing for ufuncs with the
`.at`

method. - New,
`partition`

function, partial sorting via selection for fast median. - New,
`nanmean`

,`nanvar`

, and`nanstd`

functions skipping NaNs. - New,
`full`

and`full_like`

functions to create value initialized arrays. - New,
`PyUFunc_RegisterLoopForDescr`

, better ufunc support for user dtypes. - Numerous performance improvements in many areas.

### Dropped Support¶

Support for Python versions 2.4 and 2.5 has been dropped,

Support for SCons has been removed.

### Future Changes¶

The Datetime64 type remains experimental in this release. In 1.9 there will probably be some changes to make it more useable.

The diagonal method currently returns a new array and raises a FutureWarning. In 1.9 it will return a readonly view.

Multiple field selection from an array of structured type currently returns a new array and raises a FutureWarning. In 1.9 it will return a readonly view.

The numpy/oldnumeric and numpy/numarray compatibility modules will be removed in 1.9.

### Compatibility notes¶

The doc/sphinxext content has been moved into its own github repository, and is included in numpy as a submodule. See the instructions in doc/HOWTO_BUILD_DOCS.rst.txt for how to access the content.

The hash function of numpy.void scalars has been changed. Previously the pointer to the data was hashed as an integer. Now, the hash function uses the tuple-hash algorithm to combine the hash functions of the elements of the scalar, but only if the scalar is read-only.

Numpy has switched its build system to using ‘separate compilation’ by default. In previous releases this was supported, but not default. This should produce the same results as the old system, but if you’re trying to do something complicated like link numpy statically or using an unusual compiler, then it’s possible you will encounter problems. If so, please file a bug and as a temporary workaround you can re-enable the old build system by exporting the shell variable NPY_SEPARATE_COMPILATION=0.

For the AdvancedNew iterator the `oa_ndim`

flag should now be -1 to indicate
that no `op_axes`

and `itershape`

are passed in. The `oa_ndim == 0`

case, now indicates a 0-D iteration and `op_axes`

being NULL and the old
usage is deprecated. This does not effect the `NpyIter_New`

or
`NpyIter_MultiNew`

functions.

The functions nanargmin and nanargmax now return np.iinfo[‘intp’].min for the index in all-NaN slices. Previously the functions would raise a ValueError for array returns and NaN for scalar returns.

#### NPY_RELAXED_STRIDES_CHECKING¶

There is a new compile time environment variable
`NPY_RELAXED_STRIDES_CHECKING`

. If this variable is set to 1, then
numpy will consider more arrays to be C- or F-contiguous – for
example, it becomes possible to have a column vector which is
considered both C- and F-contiguous simultaneously. The new definition
is more accurate, allows for faster code that makes fewer unnecessary
copies, and simplifies numpy’s code internally. However, it may also
break third-party libraries that make too-strong assumptions about the
stride values of C- and F-contiguous arrays. (It is also currently
known that this breaks Cython code using memoryviews, which will be
fixed in Cython.) THIS WILL BECOME THE DEFAULT IN A FUTURE RELEASE, SO
PLEASE TEST YOUR CODE NOW AGAINST NUMPY BUILT WITH:

```
NPY_RELAXED_STRIDES_CHECKING=1 python setup.py install
```

You can check whether NPY_RELAXED_STRIDES_CHECKING is in effect by running:

```
np.ones((10, 1), order="C").flags.f_contiguous
```

This will be `True`

if relaxed strides checking is enabled, and
`False`

otherwise. The typical problem we’ve seen so far is C code
that works with C-contiguous arrays, and assumes that the itemsize can
be accessed by looking at the last element in the `PyArray_STRIDES(arr)`

array. When relaxed strides are in effect, this is not true (and in
fact, it never was true in some corner cases). Instead, use
`PyArray_ITEMSIZE(arr)`

.

For more information check the “Internal memory layout of an ndarray” section in the documentation.

#### Binary operations with non-arrays as second argument¶

Binary operations of the form `<array-or-subclass> * <non-array-subclass>`

where `<non-array-subclass>`

declares an `__array_priority__`

higher than
that of `<array-or-subclass>`

will now unconditionally return
*NotImplemented*, giving `<non-array-subclass>`

a chance to handle the
operation. Previously, *NotImplemented* would only be returned if
`<non-array-subclass>`

actually implemented the reversed operation, and after
a (potentially expensive) array conversion of `<non-array-subclass>`

had been
attempted. (bug, pull request)

#### Function *median* used with *overwrite_input* only partially sorts array¶

If *median* is used with *overwrite_input* option the input array will now only
be partially sorted instead of fully sorted.

#### Fix to financial.npv¶

The npv function had a bug. Contrary to what the documentation stated, it
summed from indexes `1`

to `M`

instead of from `0`

to `M - 1`

. The
fix changes the returned value. The mirr function called the npv function,
but worked around the problem, so that was also fixed and the return value
of the mirr function remains unchanged.

#### Runtime warnings when comparing NaN numbers¶

Comparing `NaN`

floating point numbers now raises the `invalid`

runtime
warning. If a `NaN`

is expected the warning can be ignored using np.errstate.
E.g.:

```
with np.errstate(invalid='ignore'):
operation()
```

### New Features¶

#### Support for linear algebra on stacked arrays¶

The gufunc machinery is now used for np.linalg, allowing operations on stacked arrays and vectors. For example:

```
>>> a
array([[[ 1., 1.],
[ 0., 1.]],
[[ 1., 1.],
[ 0., 1.]]])
>>> np.linalg.inv(a)
array([[[ 1., -1.],
[ 0., 1.]],
[[ 1., -1.],
[ 0., 1.]]])
```

#### In place fancy indexing for ufuncs¶

The function `at`

has been added to ufunc objects to allow in place
ufuncs with no buffering when fancy indexing is used. For example, the
following will increment the first and second items in the array, and will
increment the third item twice: `numpy.add.at(arr, [0, 1, 2, 2], 1)`

This is what many have mistakenly thought `arr[[0, 1, 2, 2]] += 1`

would do,
but that does not work as the incremented value of `arr[2]`

is simply copied
into the third slot in `arr`

twice, not incremented twice.

#### New functions *partition* and *argpartition*¶

New functions to partially sort arrays via a selection algorithm.

A `partition`

by index `k`

moves the `k`

smallest element to the front of
an array. All elements before `k`

are then smaller or equal than the value
in position `k`

and all elements following `k`

are then greater or equal
than the value in position `k`

. The ordering of the values within these
bounds is undefined.
A sequence of indices can be provided to sort all of them into their sorted
position at once iterative partitioning.
This can be used to efficiently obtain order statistics like median or
percentiles of samples.
`partition`

has a linear time complexity of `O(n)`

while a full sort has
`O(n log(n))`

.

#### New functions *nanmean*, *nanvar* and *nanstd*¶

New nan aware statistical functions are added. In these functions the results are what would be obtained if nan values were omitted from all computations.

#### New functions *full* and *full_like*¶

New convenience functions to create arrays filled with a specific value;
complementary to the existing *zeros* and *zeros_like* functions.

#### IO compatibility with large files¶

Large NPZ files >2GB can be loaded on 64-bit systems.

#### Building against OpenBLAS¶

It is now possible to build numpy against OpenBLAS by editing site.cfg.

#### New constant¶

Euler’s constant is now exposed in numpy as euler_gamma.

#### New modes for qr¶

New modes ‘complete’, ‘reduced’, and ‘raw’ have been added to the qr factorization and the old ‘full’ and ‘economic’ modes are deprecated. The ‘reduced’ mode replaces the old ‘full’ mode and is the default as was the ‘full’ mode, so backward compatibility can be maintained by not specifying the mode.

The ‘complete’ mode returns a full dimensional factorization, which can be useful for obtaining a basis for the orthogonal complement of the range space. The ‘raw’ mode returns arrays that contain the Householder reflectors and scaling factors that can be used in the future to apply q without needing to convert to a matrix. The ‘economic’ mode is simply deprecated, there isn’t much use for it and it isn’t any more efficient than the ‘raw’ mode.

#### New *invert* argument to *in1d*¶

The function *in1d* now accepts a *invert* argument which, when *True*,
causes the returned array to be inverted.

#### Advanced indexing using *np.newaxis*¶

It is now possible to use *np.newaxis*/*None* together with index
arrays instead of only in simple indices. This means that
`array[np.newaxis, [0, 1]]`

will now work as expected and select the first
two rows while prepending a new axis to the array.

#### C-API¶

New ufuncs can now be registered with builtin input types and a custom output type. Before this change, NumPy wouldn’t be able to find the right ufunc loop function when the ufunc was called from Python, because the ufunc loop signature matching logic wasn’t looking at the output operand type. Now the correct ufunc loop is found, as long as the user provides an output argument with the correct output type.

#### runtests.py¶

A simple test runner script `runtests.py`

was added. It also builds Numpy via
`setup.py build`

and can be used to run tests easily during development.

### Improvements¶

#### IO performance improvements¶

Performance in reading large files was improved by chunking (see also IO compatibility).

#### Performance improvements to *pad*¶

The *pad* function has a new implementation, greatly improving performance for
all inputs except *mode=* (retained for backwards compatibility).
Scaling with dimensionality is dramatically improved for rank >= 4.

#### Performance improvements to *isnan*, *isinf*, *isfinite* and *byteswap*¶

*isnan*, *isinf*, *isfinite* and *byteswap* have been improved to take
advantage of compiler builtins to avoid expensive calls to libc.
This improves performance of these operations by about a factor of two on gnu
libc systems.

#### Performance improvements via SSE2 vectorization¶

Several functions have been optimized to make use of SSE2 CPU SIMD instructions.

- Float32 and float64:
- base math (
*add*,*subtract*,*divide*,*multiply*) *sqrt**minimum/maximum**absolute*

- base math (

- Bool:
*logical_or**logical_and**logical_not*

This improves performance of these operations up to 4x/2x for float32/float64 and up to 10x for bool depending on the location of the data in the CPU caches. The performance gain is greatest for in-place operations.

In order to use the improved functions the SSE2 instruction set must be enabled at compile time. It is enabled by default on x86_64 systems. On x86_32 with a capable CPU it must be enabled by passing the appropriate flag to the CFLAGS build variable (-msse2 with gcc).

#### Performance improvements to *median*¶

*median* is now implemented in terms of *partition* instead of *sort* which
reduces its time complexity from O(n log(n)) to O(n).
If used with the *overwrite_input* option the array will now only be partially
sorted instead of fully sorted.

#### Overrideable operand flags in ufunc C-API¶

When creating a ufunc, the default ufunc operand flags can be overridden via the new op_flags attribute of the ufunc object. For example, to set the operand flag for the first input to read/write:

PyObject *ufunc = PyUFunc_FromFuncAndData(…); ufunc->op_flags[0] = NPY_ITER_READWRITE;

This allows a ufunc to perform an operation in place. Also, global nditer flags can be overridden via the new iter_flags attribute of the ufunc object. For example, to set the reduce flag for a ufunc:

ufunc->iter_flags = NPY_ITER_REDUCE_OK;

### Changes¶

#### General¶

The function np.take now allows 0-d arrays as indices.

The separate compilation mode is now enabled by default.

Several changes to np.insert and np.delete:

- Previously, negative indices and indices that pointed past the end of the array were simply ignored. Now, this will raise a Future or Deprecation Warning. In the future they will be treated like normal indexing treats them – negative indices will wrap around, and out-of-bound indices will generate an error.
- Previously, boolean indices were treated as if they were integers (always referring to either the 0th or 1st item in the array). In the future, they will be treated as masks. In this release, they raise a FutureWarning warning of this coming change.
- In Numpy 1.7. np.insert already allowed the syntax
*np.insert(arr, 3, [1,2,3])*to insert multiple items at a single position. In Numpy 1.8. this is also possible for*np.insert(arr, [3], [1, 2, 3])*.

Padded regions from np.pad are now correctly rounded, not truncated.

#### C-API Array Additions¶

Four new functions have been added to the array C-API.

- PyArray_Partition
- PyArray_ArgPartition
- PyArray_SelectkindConverter
- PyDataMem_NEW_ZEROED

#### C-API Ufunc Additions¶

One new function has been added to the ufunc C-API that allows to register an inner loop for user types using the descr.

- PyUFunc_RegisterLoopForDescr

#### C-API Developer Improvements¶

The `PyArray_Type`

instance creation function `tp_new`

now
uses `tp_basicsize`

to determine how much memory to allocate.
In previous releases only `sizeof(PyArrayObject)`

bytes of
memory were allocated, often requiring C-API subtypes to
reimplement `tp_new`

.

### Deprecations¶

The ‘full’ and ‘economic’ modes of qr factorization are deprecated.

#### General¶

The use of non-integer for indices and most integer arguments has been
deprecated. Previously float indices and function arguments such as axes or
shapes were truncated to integers without warning. For example
*arr.reshape(3., -1)* or *arr[0.]* will trigger a deprecation warning in
NumPy 1.8., and in some future version of NumPy they will raise an error.

### Authors¶

This release contains work by the following people who contributed at least one patch to this release. The names are in alphabetical order by first name:

- 87
- Adam Ginsburg +
- Adam Griffiths +
- Alexander Belopolsky +
- Alex Barth +
- Alex Ford +
- Andreas Hilboll +
- Andreas Kloeckner +
- Andreas Schwab +
- Andrew Horton +
- argriffing +
- Arink Verma +
- Bago Amirbekian +
- Bartosz Telenczuk +
- bebert218 +
- Benjamin Root +
- Bill Spotz +
- Bradley M. Froehle
- Carwyn Pelley +
- Charles Harris
- Chris
- Christian Brueffer +
- Christoph Dann +
- Christoph Gohlke
- Dan Hipschman +
- Daniel +
- Dan Miller +
- daveydave400 +
- David Cournapeau
- David Warde-Farley
- Denis Laxalde
- dmuellner +
- Edward Catmur +
- Egor Zindy +
- endolith
- Eric Firing
- Eric Fode
- Eric Moore +
- Eric Price +
- Fazlul Shahriar +
- Félix Hartmann +
- Fernando Perez
- Frank B +
- Frank Breitling +
- Frederic
- Gabriel
- GaelVaroquaux
- Guillaume Gay +
- Han Genuit
- HaroldMills +
- hklemm +
- jamestwebber +
- Jason Madden +
- Jay Bourque
- jeromekelleher +
- Jesús Gómez +
- jmozmoz +
- jnothman +
- Johannes Schönberger +
- John Benediktsson +
- John Salvatier +
- John Stechschulte +
- Jonathan Waltman +
- Joon Ro +
- Jos de Kloe +
- Joseph Martinot-Lagarde +
- Josh Warner (Mac) +
- Jostein Bø Fløystad +
- Juan Luis Cano Rodríguez +
- Julian Taylor +
- Julien Phalip +
- K.-Michael Aye +
- Kumar Appaiah +
- Lars Buitinck
- Leon Weber +
- Luis Pedro Coelho
- Marcin Juszkiewicz
- Mark Wiebe
- Marten van Kerkwijk +
- Martin Baeuml +
- Martin Spacek
- Martin Teichmann +
- Matt Davis +
- Matthew Brett
- Maximilian Albert +
- m-d-w +
- Michael Droettboom
- mwtoews +
- Nathaniel J. Smith
- Nicolas Scheffer +
- Nils Werner +
- ochoadavid +
- Ondřej Čertík
- ovillellas +
- Paul Ivanov
- Pauli Virtanen
- peterjc
- Ralf Gommers
- Raul Cota +
- Richard Hattersley +
- Robert Costa +
- Robert Kern
- Rob Ruana +
- Ronan Lamy
- Sandro Tosi
- Sascha Peilicke +
- Sebastian Berg
- Skipper Seabold
- Stefan van der Walt
- Steve +
- Takafumi Arakaki +
- Thomas Robitaille +
- Tomas Tomecek +
- Travis E. Oliphant
- Valentin Haenel
- Vladimir Rutsky +
- Warren Weckesser
- Yaroslav Halchenko
- Yury V. Zaytsev +

A total of 119 people contributed to this release. People with a “+” by their names contributed a patch for the first time.

## NumPy 1.7.2 Release Notes¶

This is a bugfix only release in the 1.7.x series. It supports Python 2.4 - 2.7 and 3.1 - 3.3 and is the last series that supports Python 2.4 - 2.5.

### Issues fixed¶

- gh-3153: Do not reuse nditer buffers when not filled enough
- gh-3192: f2py crashes with UnboundLocalError exception
- gh-442: Concatenate with axis=None now requires equal number of array elements
- gh-2485: Fix for astype(‘S’) string truncate issue
- gh-3312: bug in count_nonzero
- gh-2684: numpy.ma.average casts complex to float under certain conditions
- gh-2403: masked array with named components does not behave as expected
- gh-2495: np.ma.compress treated inputs in wrong order
- gh-576: add __len__ method to ma.mvoid
- gh-3364: reduce performance regression of mmap slicing
- gh-3421: fix non-swapping strided copies in GetStridedCopySwap
- gh-3373: fix small leak in datetime metadata initialization
- gh-2791: add platform specific python include directories to search paths
- gh-3168: fix undefined function and add integer divisions
- gh-3301: memmap does not work with TemporaryFile in python3
- gh-3057: distutils.misc_util.get_shared_lib_extension returns wrong debug extension
- gh-3472: add module extensions to load_library search list
- gh-3324: Make comparison function (gt, ge, …) respect __array_priority__
- gh-3497: np.insert behaves incorrectly with argument ‘axis=-1’
- gh-3541: make preprocessor tests consistent in halffloat.c
- gh-3458: array_ass_boolean_subscript() writes ‘non-existent’ data to array
- gh-2892: Regression in ufunc.reduceat with zero-sized index array
- gh-3608: Regression when filling struct from tuple
- gh-3701: add support for Python 3.4 ast.NameConstant
- gh-3712: do not assume that GIL is enabled in xerbla
- gh-3712: fix LAPACK error handling in lapack_litemodule
- gh-3728: f2py fix decref on wrong object
- gh-3743: Hash changed signature in Python 3.3
- gh-3793: scalar int hashing broken on 64 bit python3
- gh-3160: SandboxViolation easyinstalling 1.7.0 on Mac OS X 10.8.3
- gh-3871: npy_math.h has invalid isinf for Solaris with SUNWspro12.2
- gh-2561: Disable check for oldstyle classes in python3
- gh-3900: Ensure NotImplemented is passed on in MaskedArray ufunc’s
- gh-2052: del scalar subscript causes segfault
- gh-3832: fix a few uninitialized uses and memleaks
- gh-3971: f2py changed string.lowercase to string.ascii_lowercase for python3
- gh-3480: numpy.random.binomial raised ValueError for n == 0
- gh-3992: hypot(inf, 0) shouldn’t raise a warning, hypot(inf, inf) wrong result
- gh-4018: Segmentation fault dealing with very large arrays
- gh-4094: fix NaT handling in _strided_to_strided_string_to_datetime
- gh-4051: fix uninitialized use in _strided_to_strided_string_to_datetime
- gh-4123: lexsort segfault
- gh-4141: Fix a few issues that show up with python 3.4b1

## NumPy 1.7.1 Release Notes¶

This is a bugfix only release in the 1.7.x series. It supports Python 2.4 - 2.7 and 3.1 - 3.3 and is the last series that supports Python 2.4 - 2.5.

### Issues fixed¶

- gh-2973: Fix
*1*is printed during numpy.test() - gh-2983: BUG: gh-2969: Backport memory leak fix 80b3a34.
- gh-3007: Backport gh-3006
- gh-2984: Backport fix complex polynomial fit
- gh-2982: BUG: Make nansum work with booleans.
- gh-2985: Backport large sort fixes
- gh-3039: Backport object take
- gh-3105: Backport nditer fix op axes initialization
- gh-3108: BUG: npy-pkg-config ini files were missing after Bento build.
- gh-3124: BUG: PyArray_LexSort allocates too much temporary memory.
- gh-3131: BUG: Exported f2py_size symbol prevents linking multiple f2py modules.
- gh-3117: Backport gh-2992
- gh-3135: DOC: Add mention of PyArray_SetBaseObject stealing a reference
- gh-3134: DOC: Fix typo in fft docs (the indexing variable is ‘m’, not ‘n’).
- gh-3136: Backport #3128

## NumPy 1.7.0 Release Notes¶

This release includes several new features as well as numerous bug fixes and refactorings. It supports Python 2.4 - 2.7 and 3.1 - 3.3 and is the last release that supports Python 2.4 - 2.5.

### Highlights¶

`where=`

parameter to ufuncs (allows the use of boolean arrays to choose where a computation should be done)`vectorize`

improvements (added ‘excluded’ and ‘cache’ keyword, general cleanup and bug fixes)`numpy.random.choice`

(random sample generating function)

### Compatibility notes¶

In a future version of numpy, the functions np.diag, np.diagonal, and the diagonal method of ndarrays will return a view onto the original array, instead of producing a copy as they do now. This makes a difference if you write to the array returned by any of these functions. To facilitate this transition, numpy 1.7 produces a FutureWarning if it detects that you may be attempting to write to such an array. See the documentation for np.diagonal for details.

Similar to np.diagonal above, in a future version of numpy, indexing a record array by a list of field names will return a view onto the original array, instead of producing a copy as they do now. As with np.diagonal, numpy 1.7 produces a FutureWarning if it detects that you may be attempting to write to such an array. See the documentation for array indexing for details.

In a future version of numpy, the default casting rule for UFunc out= parameters will be changed from ‘unsafe’ to ‘same_kind’. (This also applies to in-place operations like a += b, which is equivalent to np.add(a, b, out=a).) Most usages which violate the ‘same_kind’ rule are likely bugs, so this change may expose previously undetected errors in projects that depend on NumPy. In this version of numpy, such usages will continue to succeed, but will raise a DeprecationWarning.

Full-array boolean indexing has been optimized to use a different, optimized code path. This code path should produce the same results, but any feedback about changes to your code would be appreciated.

Attempting to write to a read-only array (one with `arr.flags.writeable`

set to `False`

) used to raise either a RuntimeError, ValueError, or
TypeError inconsistently, depending on which code path was taken. It now
consistently raises a ValueError.

The <ufunc>.reduce functions evaluate some reductions in a different order than in previous versions of NumPy, generally providing higher performance. Because of the nature of floating-point arithmetic, this may subtly change some results, just as linking NumPy to a different BLAS implementations such as MKL can.

If upgrading from 1.5, then generally in 1.6 and 1.7 there have been substantial code added and some code paths altered, particularly in the areas of type resolution and buffered iteration over universal functions. This might have an impact on your code particularly if you relied on accidental behavior in the past.

### New features¶

#### Reduction UFuncs Generalize axis= Parameter¶

Any ufunc.reduce function call, as well as other reductions like sum, prod, any, all, max and min support the ability to choose a subset of the axes to reduce over. Previously, one could say axis=None to mean all the axes or axis=# to pick a single axis. Now, one can also say axis=(#,#) to pick a list of axes for reduction.

#### Reduction UFuncs New keepdims= Parameter¶

There is a new keepdims= parameter, which if set to True, doesn’t throw away the reduction axes but instead sets them to have size one. When this option is set, the reduction result will broadcast correctly to the original operand which was reduced.

#### Datetime support¶

Note

The datetime API is *experimental* in 1.7.0, and may undergo changes
in future versions of NumPy.

There have been a lot of fixes and enhancements to datetime64 compared to NumPy 1.6:

- the parser is quite strict about only accepting ISO 8601 dates, with a few convenience extensions
- converts between units correctly
- datetime arithmetic works correctly
- business day functionality (allows the datetime to be used in contexts where only certain days of the week are valid)

The notes in doc/source/reference/arrays.datetime.rst (also available in the online docs at arrays.datetime.html) should be consulted for more details.

#### Custom formatter for printing arrays¶

See the new `formatter`

parameter of the `numpy.set_printoptions`

function.

#### New function numpy.random.choice¶

A generic sampling function has been added which will generate samples from a given array-like. The samples can be with or without replacement, and with uniform or given non-uniform probabilities.

#### New function isclose¶

Returns a boolean array where two arrays are element-wise equal within a tolerance. Both relative and absolute tolerance can be specified.

#### Preliminary multi-dimensional support in the polynomial package¶

Axis keywords have been added to the integration and differentiation functions and a tensor keyword was added to the evaluation functions. These additions allow multi-dimensional coefficient arrays to be used in those functions. New functions for evaluating 2-D and 3-D coefficient arrays on grids or sets of points were added together with 2-D and 3-D pseudo-Vandermonde matrices that can be used for fitting.

#### Ability to pad rank-n arrays¶

A pad module containing functions for padding n-dimensional arrays has been added. The various private padding functions are exposed as options to a public ‘pad’ function. Example:

```
pad(a, 5, mode='mean')
```

Current modes are `constant`

, `edge`

, `linear_ramp`

, `maximum`

,
`mean`

, `median`

, `minimum`

, `reflect`

, `symmetric`

, `wrap`

, and
`<function>`

.

#### New argument to searchsorted¶

The function searchsorted now accepts a ‘sorter’ argument that is a permutation array that sorts the array to search.

#### Build system¶

Added experimental support for the AArch64 architecture.

#### C API¶

New function `PyArray_RequireWriteable`

provides a consistent interface
for checking array writeability – any C code which works with arrays whose
WRITEABLE flag is not known to be True a priori, should make sure to call
this function before writing.

NumPy C Style Guide added (`doc/C_STYLE_GUIDE.rst.txt`

).

### Changes¶

#### General¶

The function np.concatenate tries to match the layout of its input arrays. Previously, the layout did not follow any particular reason, and depended in an undesirable way on the particular axis chosen for concatenation. A bug was also fixed which silently allowed out of bounds axis arguments.

The ufuncs logical_or, logical_and, and logical_not now follow Python’s behavior with object arrays, instead of trying to call methods on the objects. For example the expression (3 and ‘test’) produces the string ‘test’, and now np.logical_and(np.array(3, ‘O’), np.array(‘test’, ‘O’)) produces ‘test’ as well.

The `.base`

attribute on ndarrays, which is used on views to ensure that the
underlying array owning the memory is not deallocated prematurely, now
collapses out references when you have a view-of-a-view. For example:

```
a = np.arange(10)
b = a[1:]
c = b[1:]
```

In numpy 1.6, `c.base`

is `b`

, and `c.base.base`

is `a`

. In numpy 1.7,
`c.base`

is `a`

.

To increase backwards compatibility for software which relies on the old
behaviour of `.base`

, we only ‘skip over’ objects which have exactly the same
type as the newly created view. This makes a difference if you use `ndarray`

subclasses. For example, if we have a mix of `ndarray`

and `matrix`

objects
which are all views on the same original `ndarray`

:

```
a = np.arange(10)
b = np.asmatrix(a)
c = b[0, 1:]
d = c[0, 1:]
```

then `d.base`

will be `b`

. This is because `d`

is a `matrix`

object,
and so the collapsing process only continues so long as it encounters other
`matrix`

objects. It considers `c`

, `b`

, and `a`

in that order, and
`b`

is the last entry in that list which is a `matrix`

object.

#### Casting Rules¶

Casting rules have undergone some changes in corner cases, due to the NA-related work. In particular for combinations of scalar+scalar:

- the
*longlong*type (*q*) now stays*longlong*for operations with any other number (*? b h i l q p B H I*), previously it was cast as*int_*(*l*). The*ulonglong*type (*Q*) now stays as*ulonglong*instead of*uint*(*L*). - the
*timedelta64*type (*m*) can now be mixed with any integer type (*b h i l q p B H I L Q P*), previously it raised*TypeError*.

For array + scalar, the above rules just broadcast except the case when the array and scalars are unsigned/signed integers, then the result gets converted to the array type (of possibly larger size) as illustrated by the following examples:

```
>>> (np.zeros((2,), dtype=np.uint8) + np.int16(257)).dtype
dtype('uint16')
>>> (np.zeros((2,), dtype=np.int8) + np.uint16(257)).dtype
dtype('int16')
>>> (np.zeros((2,), dtype=np.int16) + np.uint32(2**17)).dtype
dtype('int32')
```

Whether the size gets increased depends on the size of the scalar, for example:

```
>>> (np.zeros((2,), dtype=np.uint8) + np.int16(255)).dtype
dtype('uint8')
>>> (np.zeros((2,), dtype=np.uint8) + np.int16(256)).dtype
dtype('uint16')
```

Also a `complex128`

scalar + `float32`

array is cast to `complex64`

.

In NumPy 1.7 the *datetime64* type (*M*) must be constructed by explicitly
specifying the type as the second argument (e.g. `np.datetime64(2000, 'Y')`

).

### Deprecations¶

#### General¶

Specifying a custom string formatter with a *_format* array attribute is
deprecated. The new `formatter`

keyword in `numpy.set_printoptions`

or
`numpy.array2string`

can be used instead.

The deprecated imports in the polynomial package have been removed.

`concatenate`

now raises DepractionWarning for 1D arrays if `axis != 0`

.
Versions of numpy < 1.7.0 ignored axis argument value for 1D arrays. We
allow this for now, but in due course we will raise an error.

#### C-API¶

Direct access to the fields of PyArrayObject* has been deprecated. Direct access has been recommended against for many releases. Expect similar deprecations for PyArray_Descr* and other core objects in the future as preparation for NumPy 2.0.

The macros in old_defines.h are deprecated and will be removed in the next major release (>= 2.0). The sed script tools/replace_old_macros.sed can be used to replace these macros with the newer versions.

You can test your code against the deprecated C API by adding a line
composed of `#define NPY_NO_DEPRECATED_API`

and the target version number,
such as `NPY_1_7_API_VERSION`

, before including any NumPy headers.

The `NPY_CHAR`

member of the `NPY_TYPES`

enum is deprecated and will be
removed in NumPy 1.8. See the discussion at
gh-2801 for more details.

## NumPy 1.6.2 Release Notes¶

This is a bugfix release in the 1.6.x series. Due to the delay of the NumPy 1.7.0 release, this release contains far more fixes than a regular NumPy bugfix release. It also includes a number of documentation and build improvements.

### Issues fixed¶

`numpy.core`

¶

- #2063: make unique() return consistent index
- #1138: allow creating arrays from empty buffers or empty slices
- #1446: correct note about correspondence vstack and concatenate
- #1149: make argmin() work for datetime
- #1672: fix allclose() to work for scalar inf
- #1747: make np.median() work for 0-D arrays
- #1776: make complex division by zero to yield inf properly
- #1675: add scalar support for the format() function
- #1905: explicitly check for NaNs in allclose()
- #1952: allow floating ddof in std() and var()
- #1948: fix regression for indexing chararrays with empty list
- #2017: fix type hashing
- #2046: deleting array attributes causes segfault
- #2033: a**2.0 has incorrect type
- #2045: make attribute/iterator_element deletions not segfault
- #2021: fix segfault in searchsorted()
- #2073: fix float16 __array_interface__ bug

`numpy.lib`

¶

- #2048: break reference cycle in NpzFile
- #1573: savetxt() now handles complex arrays
- #1387: allow bincount() to accept empty arrays
- #1899: fixed histogramdd() bug with empty inputs
- #1793: fix failing npyio test under py3k
- #1936: fix extra nesting for subarray dtypes
- #1848: make tril/triu return the same dtype as the original array
- #1918: use Py_TYPE to access ob_type, so it works also on Py3

`numpy.distutils`

¶

- #1261: change compile flag on AIX from -O5 to -O3
- #1377: update HP compiler flags
- #1383: provide better support for C++ code on HPUX
- #1857: fix build for py3k + pip
- BLD: raise a clearer warning in case of building without cleaning up first
- BLD: follow build_ext coding convention in build_clib
- BLD: fix up detection of Intel CPU on OS X in system_info.py
- BLD: add support for the new X11 directory structure on Ubuntu & co.
- BLD: add ufsparse to the libraries search path.
- BLD: add ‘pgfortran’ as a valid compiler in the Portland Group
- BLD: update version match regexp for IBM AIX Fortran compilers.

`numpy.random`

¶

- BUG: Use npy_intp instead of long in mtrand

### Changes¶

`numpy.f2py`

¶

- ENH: Introduce new options extra_f77_compiler_args and extra_f90_compiler_args
- BLD: Improve reporting of fcompiler value
- BUG: Fix f2py test_kind.py test

`numpy.poly`

¶

- ENH: Add some tests for polynomial printing
- ENH: Add companion matrix functions
- DOC: Rearrange the polynomial documents
- BUG: Fix up links to classes
- DOC: Add version added to some of the polynomial package modules
- DOC: Document xxxfit functions in the polynomial package modules
- BUG: The polynomial convenience classes let different types interact
- DOC: Document the use of the polynomial convenience classes
- DOC: Improve numpy reference documentation of polynomial classes
- ENH: Improve the computation of polynomials from roots
- STY: Code cleanup in polynomial [*]fromroots functions
- DOC: Remove references to cast and NA, which were added in 1.7

## NumPy 1.6.1 Release Notes¶

This is a bugfix only release in the 1.6.x series.

### Issues Fixed¶

- #1834: einsum fails for specific shapes
- #1837: einsum throws nan or freezes python for specific array shapes
- #1838: object <-> structured type arrays regression
- #1851: regression for SWIG based code in 1.6.0
- #1863: Buggy results when operating on array copied with astype()
- #1870: Fix corner case of object array assignment
- #1843: Py3k: fix error with recarray
- #1885: nditer: Error in detecting double reduction loop
- #1874: f2py: fix –include_paths bug
- #1749: Fix ctypes.load_library()
- #1895/1896: iter: writeonly operands weren’t always being buffered correctly

## NumPy 1.6.0 Release Notes¶

This release includes several new features as well as numerous bug fixes and improved documentation. It is backward compatible with the 1.5.0 release, and supports Python 2.4 - 2.7 and 3.1 - 3.2.

### Highlights¶

- Re-introduction of datetime dtype support to deal with dates in arrays.
- A new 16-bit floating point type.
- A new iterator, which improves performance of many functions.

### New features¶

#### New 16-bit floating point type¶

This release adds support for the IEEE 754-2008 binary16 format, available as
the data type `numpy.half`

. Within Python, the type behaves similarly to
*float* or *double*, and C extensions can add support for it with the exposed
half-float API.

#### New iterator¶

A new iterator has been added, replacing the functionality of the existing iterator and multi-iterator with a single object and API. This iterator works well with general memory layouts different from C or Fortran contiguous, and handles both standard NumPy and customized broadcasting. The buffering, automatic data type conversion, and optional output parameters, offered by ufuncs but difficult to replicate elsewhere, are now exposed by this iterator.

#### Legendre, Laguerre, Hermite, HermiteE polynomials in `numpy.polynomial`

¶

Extend the number of polynomials available in the polynomial package. In
addition, a new `window`

attribute has been added to the classes in
order to specify the range the `domain`

maps to. This is mostly useful
for the Laguerre, Hermite, and HermiteE polynomials whose natural domains
are infinite and provides a more intuitive way to get the correct mapping
of values without playing unnatural tricks with the domain.

#### Fortran assumed shape array and size function support in `numpy.f2py`

¶

F2py now supports wrapping Fortran 90 routines that use assumed shape arrays. Before such routines could be called from Python but the corresponding Fortran routines received assumed shape arrays as zero length arrays which caused unpredicted results. Thanks to Lorenz Hüdepohl for pointing out the correct way to interface routines with assumed shape arrays.

In addition, f2py supports now automatic wrapping of Fortran routines
that use two argument `size`

function in dimension specifications.

#### Other new functions¶

`numpy.ravel_multi_index`

: Converts a multi-index tuple into
an array of flat indices, applying boundary modes to the indices.

`numpy.einsum`

: Evaluate the Einstein summation convention. Using the
Einstein summation convention, many common multi-dimensional array operations
can be represented in a simple fashion. This function provides a way compute
such summations.

`numpy.count_nonzero`

: Counts the number of non-zero elements in an array.

`numpy.result_type`

and `numpy.min_scalar_type`

: These functions expose
the underlying type promotion used by the ufuncs and other operations to
determine the types of outputs. These improve upon the `numpy.common_type`

and `numpy.mintypecode`

which provide similar functionality but do
not match the ufunc implementation.

### Changes¶

`default error handling`

¶

The default error handling has been change from `print`

to `warn`

for
all except for `underflow`

, which remains as `ignore`

.

`numpy.distutils`

¶

Several new compilers are supported for building Numpy: the Portland Group Fortran compiler on OS X, the PathScale compiler suite and the 64-bit Intel C compiler on Linux.

`numpy.testing`

¶

The testing framework gained `numpy.testing.assert_allclose`

, which provides
a more convenient way to compare floating point arrays than
*assert_almost_equal*, *assert_approx_equal* and *assert_array_almost_equal*.

`C API`

¶

In addition to the APIs for the new iterator and half data type, a number
of other additions have been made to the C API. The type promotion
mechanism used by ufuncs is exposed via `PyArray_PromoteTypes`

,
`PyArray_ResultType`

, and `PyArray_MinScalarType`

. A new enumeration
`NPY_CASTING`

has been added which controls what types of casts are
permitted. This is used by the new functions `PyArray_CanCastArrayTo`

and `PyArray_CanCastTypeTo`

. A more flexible way to handle
conversion of arbitrary python objects into arrays is exposed by
`PyArray_GetArrayParamsFromObject`

.

### Deprecated features¶

The “normed” keyword in `numpy.histogram`

is deprecated. Its functionality
will be replaced by the new “density” keyword.

### Removed features¶

`numpy.fft`

¶

The functions *refft*, *refft2*, *refftn*, *irefft*, *irefft2*, *irefftn*,
which were aliases for the same functions without the ‘e’ in the name, were
removed.

`numpy.memmap`

¶

The *sync()* and *close()* methods of memmap were removed. Use *flush()* and
“del memmap” instead.

`numpy.lib`

¶

The deprecated functions `numpy.unique1d`

, `numpy.setmember1d`

,
`numpy.intersect1d_nu`

and `numpy.lib.ufunclike.log2`

were removed.

`numpy.ma`

¶

Several deprecated items were removed from the `numpy.ma`

module:

```
* ``numpy.ma.MaskedArray`` "raw_data" method
* ``numpy.ma.MaskedArray`` constructor "flag" keyword
* ``numpy.ma.make_mask`` "flag" keyword
* ``numpy.ma.allclose`` "fill_value" keyword
```

`numpy.distutils`

¶

The `numpy.get_numpy_include`

function was removed, use `numpy.get_include`

instead.

## NumPy 1.5.0 Release Notes¶

### Highlights¶

#### Python 3 compatibility¶

This is the first NumPy release which is compatible with Python 3. Support for Python 3 and Python 2 is done from a single code base. Extensive notes on changes can be found at http://projects.scipy.org/numpy/browser/trunk/doc/Py3K.txt.

Note that the Numpy testing framework relies on nose, which does not have a Python 3 compatible release yet. A working Python 3 branch of nose can be found at http://bitbucket.org/jpellerin/nose3/ however.

Porting of SciPy to Python 3 is expected to be completed soon.

### New features¶

#### Warning on casting complex to real¶

Numpy now emits a `numpy.ComplexWarning`

when a complex number is cast
into a real number. For example:

```
>>> x = np.array([1,2,3])
>>> x[:2] = np.array([1+2j, 1-2j])
ComplexWarning: Casting complex values to real discards the imaginary part
```

The cast indeed discards the imaginary part, and this may not be the intended behavior in all cases, hence the warning. This warning can be turned off in the standard way:

```
>>> import warnings
>>> warnings.simplefilter("ignore", np.ComplexWarning)
```

#### Dot method for ndarrays¶

Ndarrays now have the dot product also as a method, which allows writing chains of matrix products as

```
>>> a.dot(b).dot(c)
```

instead of the longer alternative

```
>>> np.dot(a, np.dot(b, c))
```

#### linalg.slogdet function¶

The slogdet function returns the sign and logarithm of the determinant of a matrix. Because the determinant may involve the product of many small/large values, the result is often more accurate than that obtained by simple multiplication.

#### new header¶

The new header file ndarraytypes.h contains the symbols from ndarrayobject.h that do not depend on the PY_ARRAY_UNIQUE_SYMBOL and NO_IMPORT/_ARRAY macros. Broadly, these symbols are types, typedefs, and enumerations; the array function calls are left in ndarrayobject.h. This allows users to include array-related types and enumerations without needing to concern themselves with the macro expansions and their side- effects.

### Changes¶

#### polynomial.polynomial¶

- The polyint and polyder functions now check that the specified number integrations or derivations is a non-negative integer. The number 0 is a valid value for both functions.
- A degree method has been added to the Polynomial class.
- A trimdeg method has been added to the Polynomial class. It operates like truncate except that the argument is the desired degree of the result, not the number of coefficients.
- Polynomial.fit now uses None as the default domain for the fit. The default Polynomial domain can be specified by using [] as the domain value.
- Weights can be used in both polyfit and Polynomial.fit
- A linspace method has been added to the Polynomial class to ease plotting.
- The polymulx function was added.

#### polynomial.chebyshev¶

- The chebint and chebder functions now check that the specified number integrations or derivations is a non-negative integer. The number 0 is a valid value for both functions.
- A degree method has been added to the Chebyshev class.
- A trimdeg method has been added to the Chebyshev class. It operates like truncate except that the argument is the desired degree of the result, not the number of coefficients.
- Chebyshev.fit now uses None as the default domain for the fit. The default Chebyshev domain can be specified by using [] as the domain value.
- Weights can be used in both chebfit and Chebyshev.fit
- A linspace method has been added to the Chebyshev class to ease plotting.
- The chebmulx function was added.
- Added functions for the Chebyshev points of the first and second kind.

#### histogram¶

After a two years transition period, the old behavior of the histogram function has been phased out, and the “new” keyword has been removed.

#### correlate¶

The old behavior of correlate was deprecated in 1.4.0, the new behavior (the usual definition for cross-correlation) is now the default.

## NumPy 1.4.0 Release Notes¶

This minor includes numerous bug fixes, as well as a few new features. It is backward compatible with 1.3.0 release.

### Highlights¶

- New datetime dtype support to deal with dates in arrays
- Faster import time
- Extended array wrapping mechanism for ufuncs
- New Neighborhood iterator (C-level only)
- C99-like complex functions in npymath

### New features¶

#### Extended array wrapping mechanism for ufuncs¶

An __array_prepare__ method has been added to ndarray to provide subclasses
greater flexibility to interact with ufuncs and ufunc-like functions. ndarray
already provided __array_wrap__, which allowed subclasses to set the array type
for the result and populate metadata on the way out of the ufunc (as seen in
the implementation of MaskedArray). For some applications it is necessary to
provide checks and populate metadata *on the way in*. __array_prepare__ is
therefore called just after the ufunc has initialized the output array but
before computing the results and populating it. This way, checks can be made
and errors raised before operations which may modify data in place.

#### Automatic detection of forward incompatibilities¶

Previously, if an extension was built against a version N of NumPy, and used on a system with NumPy M < N, the import_array was successful, which could cause crashes because the version M does not have a function in N. Starting from NumPy 1.4.0, this will cause a failure in import_array, so the error will be caught early on.

#### New iterators¶

A new neighborhood iterator has been added to the C API. It can be used to iterate over the items in a neighborhood of an array, and can handle boundaries conditions automatically. Zero and one padding are available, as well as arbitrary constant value, mirror and circular padding.

#### New polynomial support¶

New modules chebyshev and polynomial have been added. The new polynomial module
is not compatible with the current polynomial support in numpy, but is much
like the new chebyshev module. The most noticeable difference to most will
be that coefficients are specified from low to high power, that the low
level functions do *not* work with the Chebyshev and Polynomial classes as
arguments, and that the Chebyshev and Polynomial classes include a domain.
Mapping between domains is a linear substitution and the two classes can be
converted one to the other, allowing, for instance, a Chebyshev series in
one domain to be expanded as a polynomial in another domain. The new classes
should generally be used instead of the low level functions, the latter are
provided for those who wish to build their own classes.

The new modules are not automatically imported into the numpy namespace, they must be explicitly brought in with an “import numpy.polynomial” statement.

#### New C API¶

The following C functions have been added to the C API:

- PyArray_GetNDArrayCFeatureVersion: return the
APIversion of the loaded numpy.- PyArray_Correlate2 - like PyArray_Correlate, but implements the usual definition of correlation. Inputs are not swapped, and conjugate is taken for complex arrays.
- PyArray_NeighborhoodIterNew - a new iterator to iterate over a neighborhood of a point, with automatic boundaries handling. It is documented in the iterators section of the C-API reference, and you can find some examples in the multiarray_test.c.src file in numpy.core.

#### New ufuncs¶

The following ufuncs have been added to the C API:

- copysign - return the value of the first argument with the sign copied from the second argument.
- nextafter - return the next representable floating point value of the first argument toward the second argument.

#### New defines¶

The alpha processor is now defined and available in numpy/npy_cpu.h. The failed detection of the PARISC processor has been fixed. The defines are:

- NPY_CPU_HPPA: PARISC
- NPY_CPU_ALPHA: Alpha

#### Testing¶

- deprecated decorator: this decorator may be used to avoid cluttering testing output while testing DeprecationWarning is effectively raised by the decorated test.
- assert_array_almost_equal_nulps: new method to compare two arrays of floating point values. With this function, two values are considered close if there are not many representable floating point values in between, thus being more robust than assert_array_almost_equal when the values fluctuate a lot.
- assert_array_max_ulp: raise an assertion if there are more than N representable numbers between two floating point values.
- assert_warns: raise an AssertionError if a callable does not generate a warning of the appropriate class, without altering the warning state.

#### Reusing npymath¶

In 1.3.0, we started putting portable C math routines in npymath library, so that people can use those to write portable extensions. Unfortunately, it was not possible to easily link against this library: in 1.4.0, support has been added to numpy.distutils so that 3rd party can reuse this library. See coremath documentation for more information.

#### Improved set operations¶

In previous versions of NumPy some set functions (intersect1d, setxor1d, setdiff1d and setmember1d) could return incorrect results if the input arrays contained duplicate items. These now work correctly for input arrays with duplicates. setmember1d has been renamed to in1d, as with the change to accept arrays with duplicates it is no longer a set operation, and is conceptually similar to an elementwise version of the Python operator ‘in’. All of these functions now accept the boolean keyword assume_unique. This is False by default, but can be set True if the input arrays are known not to contain duplicates, which can increase the functions’ execution speed.

### Improvements¶

numpy import is noticeably faster (from 20 to 30 % depending on the platform and computer)

The sort functions now sort nans to the end.

- Real sort order is [R, nan]
- Complex sort order is [R + Rj, R + nanj, nan + Rj, nan + nanj]
Complex numbers with the same nan placements are sorted according to the non-nan part if it exists.

The type comparison functions have been made consistent with the new sort order of nans. Searchsorted now works with sorted arrays containing nan values.

Complex division has been made more resistant to overflow.

Complex floor division has been made more resistant to overflow.

### Deprecations¶

The following functions are deprecated:

- correlate: it takes a new keyword argument old_behavior. When True (the default), it returns the same result as before. When False, compute the conventional correlation, and take the conjugate for complex arrays. The old behavior will be removed in NumPy 1.5, and raises a DeprecationWarning in 1.4.
- unique1d: use unique instead. unique1d raises a deprecation warning in 1.4, and will be removed in 1.5.
- intersect1d_nu: use intersect1d instead. intersect1d_nu raises a deprecation warning in 1.4, and will be removed in 1.5.
- setmember1d: use in1d instead. setmember1d raises a deprecation warning in 1.4, and will be removed in 1.5.

The following raise errors:

- When operating on 0-d arrays,
`numpy.max`

and other functions accept only`axis=0`

,`axis=-1`

and`axis=None`

. Using an out-of-bounds axes is an indication of a bug, so Numpy raises an error for these cases now.- Specifying
`axis > MAX_DIMS`

is no longer allowed; Numpy raises now an error instead of behaving similarly as for`axis=None`

.

### Internal changes¶

#### Use C99 complex functions when available¶

The numpy complex types are now guaranteed to be ABI compatible with C99 complex type, if available on the platform. Moreover, the complex ufunc now use the platform C99 functions instead of our own.

#### split multiarray and umath source code¶

The source code of multiarray and umath has been split into separate logic compilation units. This should make the source code more amenable for newcomers.

#### Separate compilation¶

By default, every file of multiarray (and umath) is merged into one for compilation as was the case before, but if NPY_SEPARATE_COMPILATION env variable is set to a non-negative value, experimental individual compilation of each file is enabled. This makes the compile/debug cycle much faster when working on core numpy.

#### Separate core math library¶

New functions which have been added:

- npy_copysign
- npy_nextafter
- npy_cpack
- npy_creal
- npy_cimag
- npy_cabs
- npy_cexp
- npy_clog
- npy_cpow
- npy_csqr
- npy_ccos
- npy_csin

## NumPy 1.3.0 Release Notes¶

This minor includes numerous bug fixes, official python 2.6 support, and several new features such as generalized ufuncs.

### Highlights¶

#### Python 2.6 support¶

Python 2.6 is now supported on all previously supported platforms, including windows.

#### Generalized ufuncs¶

There is a general need for looping over not only functions on scalars but also over functions on vectors (or arrays), as explained on http://scipy.org/scipy/numpy/wiki/GeneralLoopingFunctions. We propose to realize this concept by generalizing the universal functions (ufuncs), and provide a C implementation that adds ~500 lines to the numpy code base. In current (specialized) ufuncs, the elementary function is limited to element-by-element operations, whereas the generalized version supports “sub-array” by “sub-array” operations. The Perl vector library PDL provides a similar functionality and its terms are re-used in the following.

Each generalized ufunc has information associated with it that states what the “core” dimensionality of the inputs is, as well as the corresponding dimensionality of the outputs (the element-wise ufuncs have zero core dimensions). The list of the core dimensions for all arguments is called the “signature” of a ufunc. For example, the ufunc numpy.add has signature “(),()->()” defining two scalar inputs and one scalar output.

Another example is (see the GeneralLoopingFunctions page) the function inner1d(a,b) with a signature of “(i),(i)->()”. This applies the inner product along the last axis of each input, but keeps the remaining indices intact. For example, where a is of shape (3,5,N) and b is of shape (5,N), this will return an output of shape (3,5). The underlying elementary function is called 3*5 times. In the signature, we specify one core dimension “(i)” for each input and zero core dimensions “()” for the output, since it takes two 1-d arrays and returns a scalar. By using the same name “i”, we specify that the two corresponding dimensions should be of the same size (or one of them is of size 1 and will be broadcasted).

The dimensions beyond the core dimensions are called “loop” dimensions. In the above example, this corresponds to (3,5).

The usual numpy “broadcasting” rules apply, where the signature determines how the dimensions of each input/output object are split into core and loop dimensions:

While an input array has a smaller dimensionality than the corresponding number of core dimensions, 1’s are pre-pended to its shape. The core dimensions are removed from all inputs and the remaining dimensions are broadcasted; defining the loop dimensions. The output is given by the loop dimensions plus the output core dimensions.

#### Experimental Windows 64 bits support¶

Numpy can now be built on windows 64 bits (amd64 only, not IA64), with both MS compilers and mingw-w64 compilers:

This is *highly experimental*: DO NOT USE FOR PRODUCTION USE. See INSTALL.txt,
Windows 64 bits section for more information on limitations and how to build it
by yourself.

### New features¶

#### Formatting issues¶

Float formatting is now handled by numpy instead of the C runtime: this enables locale independent formatting, more robust fromstring and related methods. Special values (inf and nan) are also more consistent across platforms (nan vs IND/NaN, etc…), and more consistent with recent python formatting work (in 2.6 and later).

#### Nan handling in max/min¶

The maximum/minimum ufuncs now reliably propagate nans. If one of the arguments is a nan, then nan is returned. This affects np.min/np.max, amin/amax and the array methods max/min. New ufuncs fmax and fmin have been added to deal with non-propagating nans.

#### Nan handling in sign¶

The ufunc sign now returns nan for the sign of anan.

#### New ufuncs¶

- fmax - same as maximum for integer types and non-nan floats. Returns the non-nan argument if one argument is nan and returns nan if both arguments are nan.
- fmin - same as minimum for integer types and non-nan floats. Returns the non-nan argument if one argument is nan and returns nan if both arguments are nan.
- deg2rad - converts degrees to radians, same as the radians ufunc.
- rad2deg - converts radians to degrees, same as the degrees ufunc.
- log2 - base 2 logarithm.
- exp2 - base 2 exponential.
- trunc - truncate floats to nearest integer towards zero.
- logaddexp - add numbers stored as logarithms and return the logarithm of the result.
- logaddexp2 - add numbers stored as base 2 logarithms and return the base 2 logarithm of the result.

#### Masked arrays¶

Several new features and bug fixes, including:

- structured arrays should now be fully supported by MaskedArray (r6463, r6324, r6305, r6300, r6294…)
- Minor bug fixes (r6356, r6352, r6335, r6299, r6298)
- Improved support for __iter__ (r6326)
- made baseclass, sharedmask and hardmask accessible to the user (but read-only)
- doc update

#### gfortran support on windows¶

Gfortran can now be used as a fortran compiler for numpy on windows, even when the C compiler is Visual Studio (VS 2005 and above; VS 2003 will NOT work). Gfortran + Visual studio does not work on windows 64 bits (but gcc + gfortran does). It is unclear whether it will be possible to use gfortran and visual studio at all on x64.

#### Arch option for windows binary¶

Automatic arch detection can now be bypassed from the command line for the superpack installed:

numpy-1.3.0-superpack-win32.exe /arch=nosse

will install a numpy which works on any x86, even if the running computer supports SSE set.

### Deprecated features¶

#### Histogram¶

The semantics of histogram has been modified to fix long-standing issues with outliers handling. The main changes concern

- the definition of the bin edges, now including the rightmost edge, and
- the handling of upper outliers, now ignored rather than tallied in the rightmost bin.

The previous behavior is still accessible using *new=False*, but this is
deprecated, and will be removed entirely in 1.4.0.

### Documentation changes¶

A lot of documentation has been added. Both user guide and references can be built from sphinx.

### New C API¶

#### Multiarray API¶

The following functions have been added to the multiarray C API:

- PyArray_GetEndianness: to get runtime endianness

#### Ufunc API¶

The following functions have been added to the ufunc API:

- PyUFunc_FromFuncAndDataAndSignature: to declare a more general ufunc (generalized ufunc).

#### New defines¶

New public C defines are available for ARCH specific code through numpy/npy_cpu.h:

- NPY_CPU_X86: x86 arch (32 bits)
- NPY_CPU_AMD64: amd64 arch (x86_64, NOT Itanium)
- NPY_CPU_PPC: 32 bits ppc
- NPY_CPU_PPC64: 64 bits ppc
- NPY_CPU_SPARC: 32 bits sparc
- NPY_CPU_SPARC64: 64 bits sparc
- NPY_CPU_S390: S390
- NPY_CPU_IA64: ia64
- NPY_CPU_PARISC: PARISC

New macros for CPU endianness has been added as well (see internal changes below for details):

- NPY_BYTE_ORDER: integer
- NPY_LITTLE_ENDIAN/NPY_BIG_ENDIAN defines

Those provide portable alternatives to glibc endian.h macros for platforms without it.

#### Portable NAN, INFINITY, etc…¶

npy_math.h now makes available several portable macro to get NAN, INFINITY:

- NPY_NAN: equivalent to NAN, which is a GNU extension
- NPY_INFINITY: equivalent to C99 INFINITY
- NPY_PZERO, NPY_NZERO: positive and negative zero respectively

Corresponding single and extended precision macros are available as well. All references to NAN, or home-grown computation of NAN on the fly have been removed for consistency.

### Internal changes¶

#### numpy.core math configuration revamp¶

This should make the porting to new platforms easier, and more robust. In particular, the configuration stage does not need to execute any code on the target platform, which is a first step toward cross-compilation.

#### umath refactor¶

A lot of code cleanup for umath/ufunc code (charris).

#### Improvements to build warnings¶

Numpy can now build with -W -Wall without warnings

#### Separate core math library¶

The core math functions (sin, cos, etc… for basic C types) have been put into a separate library; it acts as a compatibility layer, to support most C99 maths functions (real only for now). The library includes platform-specific fixes for various maths functions, such as using those versions should be more robust than using your platform functions directly. The API for existing functions is exactly the same as the C99 math functions API; the only difference is the npy prefix (npy_cos vs cos).

The core library will be made available to any extension in 1.4.0.

#### CPU arch detection¶

npy_cpu.h defines numpy specific CPU defines, such as NPY_CPU_X86, etc… Those are portable across OS and toolchains, and set up when the header is parsed, so that they can be safely used even in the case of cross-compilation (the values is not set when numpy is built), or for multi-arch binaries (e.g. fat binaries on Max OS X).

npy_endian.h defines numpy specific endianness defines, modeled on the glibc endian.h. NPY_BYTE_ORDER is equivalent to BYTE_ORDER, and one of NPY_LITTLE_ENDIAN or NPY_BIG_ENDIAN is defined. As for CPU archs, those are set when the header is parsed by the compiler, and as such can be used for cross-compilation and multi-arch binaries.