add multithreading tests

Author: vtavana

CHANGES.rst

@@ -79,26 +79,27 @@ transform improves multi-core utilization which may offset the performance loss
 
 Added :code:`scipy.fft` backend, see #42. Fixed #46.
 
-```
-Python 3.7.5 (default, Nov 23 2019, 04:02:01)
-Type 'copyright', 'credits' or 'license' for more information
-IPython 7.11.1 -- An enhanced Interactive Python. Type '?' for help.
-
-In [1]: import numpy as np, mkl_fft, mkl_fft._scipy_fft_backend as mkl_be, scipy, scipy.fft, mkl
-
-In [2]: mkl.verbose(1)
-Out[2]: True
-
-In [3]: x = np.random.randn(8*7).reshape((7, 8))
-...: with scipy.fft.set_backend(mkl_be, only=True):
-...:     ff = scipy.fft.fft2(x, workers=4)
-...: ff2 = scipy.fft.fft2(x)
-MKL_VERBOSE Intel(R) MKL 2020.0 Product build 20191102 for Intel(R) 64 architecture Intel(R) Advanced Vector Extensions 2 (Intel(R) AVX2) enabled processors, Lnx 2.40GHz intel_thread
-MKL_VERBOSE FFT(drfo7:8:8x8:1:1,bScale:0.0178571,tLim:1,desc:0x5629ad31b800) 24.85ms CNR:OFF Dyn:1 FastMM:1 TID:0  NThr:16,FFT:4
-
-In [4]: np.allclose(ff, ff2)
-Out[4]: True
-```
+
+.. code-block:: python
+
+    Python 3.7.5 (default, Nov 23 2019, 04:02:01)
+    Type 'copyright', 'credits' or 'license' for more information
+    IPython 7.11.1 -- An enhanced Interactive Python. Type '?' for help.
+
+    In [1]: import numpy as np, mkl_fft, mkl_fft._scipy_fft as mkl_be, scipy, scipy.fft, mkl
+
+    In [2]: mkl.verbose(1)
+    Out[2]: True
+
+    In [3]: x = np.random.randn(8*7).reshape((7, 8))
+    ...: with scipy.fft.set_backend(mkl_be, only=True):
+    ...:     ff = scipy.fft.fft2(x, workers=4)
+    ...: ff2 = scipy.fft.fft2(x)
+    MKL_VERBOSE Intel(R) MKL 2020.0 Product build 20191102 for Intel(R) 64 architecture Intel(R) Advanced Vector Extensions 2 (Intel(R) AVX2) enabled processors, Lnx 2.40GHz intel_thread
+    MKL_VERBOSE FFT(drfo7:8:8x8:1:1,bScale:0.0178571,tLim:1,desc:0x5629ad31b800) 24.85ms CNR:OFF Dyn:1 FastMM:1 TID:0  NThr:16,FFT:4
+
+    In [4]: np.allclose(ff, ff2)
+    Out[4]: True
 
 
 1.0.15

mkl_fft/tests/from_scipy/__pycache__/test_from_scipy.cpython-310-pytest-8.3.5.pyc

@@ -1,7 +1,7 @@
 # This file includes tests from scipy.fft module:
 # https://github.com/scipy/scipy/blob/main/scipy/fft/tests/test_basic.py
 
-# TODO: remove when hfft functions are added
+# TODO: remove when hfft* functions are added
 # pylint: disable=no-member
 
 import multiprocessing
@@ -426,7 +426,7 @@ def test_dtypes_real(self, dtype, xp):
         res_rfft = fft.irfft(fft.rfft(x))
         # TODO: res_hfft = fft.hfft(fft.ihfft(x), x.shape[0])
         # Check both numerical results and exact dtype matches
-        xp_assert_close(res_rfft, x, rtol=1e-06)
+        xp_assert_close(res_rfft, x, rtol=1e-06, atol=1e-06)
         # TODO: xp_assert_close(res_hfft, x)
 
     @pytest.mark.parametrize("dtype", ["complex64", "complex128"])

mkl_fft/tests/from_scipy/__pycache__/test_multithreading.cpython-310-pytest-8.3.5.pyc

@@ -0,0 +1,104 @@
+# This file includes tests from scipy.fft module:
+# https://github.com/scipy/scipy/blob/main/scipy/fft/tests/test_multithreading.py.py
+
+import multiprocessing
+import os
+
+import numpy as np
+import pytest
+from numpy.testing import assert_allclose
+
+import mkl_fft.interfaces.scipy_fft as fft
+
+
+@pytest.fixture(scope="module")
+def x():
+    return np.random.randn(512, 128)  # Must be large enough to qualify for mt
+
+
+@pytest.mark.parametrize(
+    "func",
+    [
+        fft.fft,
+        fft.ifft,
+        fft.fft2,
+        fft.ifft2,
+        fft.fftn,
+        fft.ifftn,
+        fft.rfft,
+        fft.irfft,
+        fft.rfft2,
+        fft.irfft2,
+        fft.rfftn,
+        fft.irfftn,
+        # TODO: fft.hfft, fft.ihfft, fft.hfft2, fft.ihfft2, fft.hfftn, fft.ihfftn,
+        # TODO: fft.dct, fft.idct, fft.dctn, fft.idctn,
+        # TODO: fft.dst, fft.idst, fft.dstn, fft.idstn,
+    ],
+)
+@pytest.mark.parametrize("workers", [2, -1])
+def test_threaded_same(x, func, workers):
+    expected = func(x, workers=1)
+    actual = func(x, workers=workers)
+    assert_allclose(actual, expected)
+
+
+def _mt_fft(x):
+    return fft.fft(x, workers=2)
+
+
+@pytest.mark.slow
+def test_mixed_threads_processes(x):
+    # Test that the fft threadpool is safe to use before & after fork
+
+    expect = fft.fft(x, workers=2)
+
+    with multiprocessing.Pool(2) as p:
+        res = p.map(_mt_fft, [x for _ in range(4)])
+
+    for r in res:
+        assert_allclose(r, expect)
+
+    fft.fft(x, workers=2)
+
+
+def test_invalid_workers(x):
+    cpus = os.cpu_count()
+
+    fft.ifft([1], workers=-cpus)
+
+    with pytest.raises(ValueError, match="workers must not be zero"):
+        fft.fft(x, workers=0)
+
+    with pytest.raises(ValueError, match="workers value out of range"):
+        fft.ifft(x, workers=-cpus - 1)
+
+
+@pytest.mark.skip()
+def test_set_get_workers():
+    cpus = os.cpu_count()
+    assert fft.get_workers() == 1
+    with fft.set_workers(4):
+        assert fft.get_workers() == 4
+
+        with fft.set_workers(-1):
+            assert fft.get_workers() == cpus
+
+        assert fft.get_workers() == 4
+
+    assert fft.get_workers() == 1
+
+    with fft.set_workers(-cpus):
+        assert fft.get_workers() == 1
+
+
+@pytest.mark.skip("mkl_fft does not validate workers")
+def test_set_workers_invalid():
+
+    with pytest.raises(ValueError, match="workers must not be zero"):
+        with fft.set_workers(0):
+            pass
+
+    with pytest.raises(ValueError, match="workers value out of range"):
+        with fft.set_workers(-os.cpu_count() - 1):
+            pass