MAINT: in fft, make copying more explicit

1 files changed, 14 insertions, 7 deletions

diff --git a/numpy/fft/fftpack.py b/numpy/fft/fftpack.py
index 19c6bed0f..89fc1e37f 100644
--- a/numpy/fft/fftpack.py
+++ b/numpy/fft/fftpack.py
@@ -249,7 +249,8 @@ def ifft(a, n=None, axis=-1):
     >>> plt.show()
 
     """
-    a = np.array(a, dtype=complex)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=complex)
     if n is None:
         n = shape(a)[axis]
     return _raw_fft(a, n, axis, fftpack.cffti, fftpack.cfftb, _fft_cache) / n
@@ -329,7 +330,8 @@ def rfft(a, n=None, axis=-1):
     exploited to compute only the non-negative frequency terms.
 
     """
-    a = np.array(a, dtype=float)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=float)
     return _raw_fft(a, n, axis, fftpack.rffti, fftpack.rfftf, _real_fft_cache)
 
 
@@ -409,7 +411,8 @@ def irfft(a, n=None, axis=-1):
     specified, and the output array is purely real.
 
     """
-    a = np.array(a, dtype=complex)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=complex)
     if n is None:
         n = (shape(a)[axis] - 1) * 2
     return _raw_fft(a, n, axis, fftpack.rffti, fftpack.rfftb,
@@ -482,7 +485,8 @@ def hfft(a, n=None, axis=-1):
            [ 2., -2.]])
 
     """
-    a = np.array(a, dtype=complex)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=complex)
     if n is None:
         n = (shape(a)[axis] - 1) * 2
     return irfft(conjugate(a), n, axis) * n
@@ -535,7 +539,8 @@ def ihfft(a, n=None, axis=-1):
     array([ 1.-0.j,  2.-0.j,  3.-0.j,  4.-0.j])
 
     """
-    a = np.array(a, dtype=float)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=float)
     if n is None:
         n = shape(a)[axis]
     return conjugate(rfft(a, n, axis))/n
@@ -1003,7 +1008,8 @@ def rfftn(a, s=None, axes=None):
             [ 0.+0.j,  0.+0.j]]])
 
     """
-    a = np.array(a, dtype=float)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=float)
     s, axes = _cook_nd_args(a, s, axes)
     a = rfft(a, s[-1], axes[-1])
     for ii in range(len(axes)-1):
@@ -1123,7 +1129,8 @@ def irfftn(a, s=None, axes=None):
             [ 1.,  1.]]])
 
     """
-    a = np.array(a, dtype=complex)
+    # The copy may be required for multithreading.
+    a = np.array(a, copy=True, dtype=complex)
     s, axes = _cook_nd_args(a, s, axes, invreal=1)
     for ii in range(len(axes)-1):
         a = ifft(a, s[ii], axes[ii])