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Diffstat (limited to 'doc/source/reference/global_state.rst')
| -rw-r--r-- | doc/source/reference/global_state.rst | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/doc/source/reference/global_state.rst b/doc/source/reference/global_state.rst index 81685ec7d..a898450af 100644 --- a/doc/source/reference/global_state.rst +++ b/doc/source/reference/global_state.rst @@ -1,7 +1,7 @@ .. _global_state: ************ -Global State +Global state ************ NumPy has a few import-time, compile-time, or runtime options @@ -11,10 +11,10 @@ purposes and will not be interesting to the vast majority of users. -Performance-Related Options +Performance-related options =========================== -Number of Threads used for Linear Algebra +Number of threads used for Linear Algebra ----------------------------------------- NumPy itself is normally intentionally limited to a single thread @@ -49,25 +49,17 @@ is to use madvise on Kernels 4.6 and newer. These kernels presumably experience a large speedup with hugepage support. This flag is checked at import time. +SIMD feature selection +---------------------- -Interoperability-Related Options -================================ +Setting ``NPY_DISABLE_CPU_FEATURES`` will exclude simd features at runtime. +See :ref:`runtime-simd-dispatch`. -The array function protocol which allows array-like objects to -hook into the NumPy API is currently enabled by default. -This option exists since NumPy 1.16 and is enabled by default since -NumPy 1.17. It can be disabled using:: - NUMPY_EXPERIMENTAL_ARRAY_FUNCTION=0 - -See also :py:meth:`numpy.class.__array_function__` for more information. -This flag is checked at import time. - - -Debugging-Related Options +Debugging-related options ========================= -Relaxed Strides Checking +Relaxed strides checking ------------------------ The *compile-time* environment variable:: @@ -90,3 +82,17 @@ memory allocation policy, the default will be to call ``free``. If ``NUMPY_WARN_IF_NO_MEM_POLICY`` is set to ``"1"``, a ``RuntimeWarning`` will be emitted. A better alternative is to use a ``PyCapsule`` with a deallocator and set the ``ndarray.base``. + + +Testing planned future behavior +=============================== + +NumPy has some code paths which are planned to be activated in the future +but are not yet the default behavior. +You can try testing some of these which may be shipped with a new "major" +release (NumPy 2.0) by setting an environment before importing NumPy: + + NPY_NUMPY_2_BEHAVIOR=1 + +By default this will also activate the :ref:`NEP 50 <NEP50>` related setting +``NPY_PROMOTION_STATE`` (please see the NEP for details on this). |