diff options
Diffstat (limited to 'numpy/fft/fftpack.py')
| -rw-r--r-- | numpy/fft/fftpack.py | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/numpy/fft/fftpack.py b/numpy/fft/fftpack.py index 78cf214d2..e18625881 100644 --- a/numpy/fft/fftpack.py +++ b/numpy/fft/fftpack.py @@ -35,6 +35,8 @@ from __future__ import division, absolute_import, print_function __all__ = ['fft', 'ifft', 'rfft', 'irfft', 'hfft', 'ihfft', 'rfftn', 'irfftn', 'rfft2', 'irfft2', 'fft2', 'ifft2', 'fftn', 'ifftn'] +import threading + from numpy.core import (array, asarray, zeros, swapaxes, shape, conjugate, take, sqrt) from . import fftpack_lite as fftpack @@ -42,6 +44,7 @@ from .helper import _FFTCache _fft_cache = _FFTCache(max_size_in_mb=100, max_item_count=32) _real_fft_cache = _FFTCache(max_size_in_mb=100, max_item_count=32) +_cache_lock = threading.Lock() def _raw_fft(a, n=None, axis=-1, init_function=fftpack.cffti, @@ -56,10 +59,13 @@ def _raw_fft(a, n=None, axis=-1, init_function=fftpack.cffti, % n) try: - # Thread-safety note: We rely on list.pop() here to atomically - # retrieve-and-remove a wsave from the cache. This ensures that no - # other thread can get the same wsave while we're using it. - wsave = fft_cache.setdefault(n, []).pop() + # We have to ensure that only a single thread can access a wsave array + # at any given time. Thus we remove it from the cache and insert it + # again after it has been used. Multiple threads might create multiple + # copies of the wsave array. This is intentional and a limitation of + # the current C code. + with _cache_lock: + wsave = fft_cache.setdefault(n, []).pop() except (IndexError): wsave = init_function(n) @@ -86,7 +92,8 @@ def _raw_fft(a, n=None, axis=-1, init_function=fftpack.cffti, # As soon as we put wsave back into the cache, another thread could pick it # up and start using it, so we must not do this until after we're # completely done using it ourselves. - fft_cache[n].append(wsave) + with _cache_lock: + fft_cache[n].append(wsave) return r |