diff options
Diffstat (limited to 'numpy/dft/fftpack.py')
| -rw-r--r-- | numpy/dft/fftpack.py | 74 |
1 files changed, 41 insertions, 33 deletions
diff --git a/numpy/dft/fftpack.py b/numpy/dft/fftpack.py index 22e236370..4b88651ef 100644 --- a/numpy/dft/fftpack.py +++ b/numpy/dft/fftpack.py @@ -6,21 +6,22 @@ version of the FFTPACK routines. fft(a, n=None, axis=-1) ifft(a, n=None, axis=-1) -refft(a, n=None, axis=-1) -irefft(a, n=None, axis=-1) +rfft(a, n=None, axis=-1) +irfft(a, n=None, axis=-1) hfft(a, n=None, axis=-1) ihfft(a, n=None, axis=-1) fftn(a, s=None, axes=None) ifftn(a, s=None, axes=None) -refftn(a, s=None, axes=None) -irefftn(a, s=None, axes=None) +rfftn(a, s=None, axes=None) +irfftn(a, s=None, axes=None) fft2(a, s=None, axes=(-2,-1)) ifft2(a, s=None, axes=(-2, -1)) -refft2(a, s=None, axes=(-2,-1)) -irefft2(a, s=None, axes=(-2, -1)) +rfft2(a, s=None, axes=(-2,-1)) +irfft2(a, s=None, axes=(-2, -1)) """ -__all__ = ['fft','ifft', 'refft', 'irefft', 'hfft', 'ihfft', 'refftn', - 'irefftn', 'refft2', 'irefft2', 'fft2', 'ifft2', 'fftn', 'ifftn'] +__all__ = ['fft','ifft', 'rfft', 'irfft', 'hfft', 'ihfft', 'rfftn', + 'irfftn', 'rfft2', 'irfft2', 'fft2', 'ifft2', 'fftn', 'ifftn', + 'refft', 'irefft','refftn','irefftn', 'refft2', 'irefft2'] from numpy.core import asarray, zeros, swapaxes, shape, conjugate, \ take @@ -111,8 +112,8 @@ def ifft(a, n=None, axis=-1): return _raw_fft(a, n, axis, fftpack.cffti, fftpack.cfftb, _fft_cache) / n -def refft(a, n=None, axis=-1): - """refft(a, n=None, axis=-1) +def rfft(a, n=None, axis=-1): + """rfft(a, n=None, axis=-1) Will return the n point discrete Fourier transform of the real valued array a. n defaults to the length of a. n is the length of the input, not @@ -132,8 +133,8 @@ def refft(a, n=None, axis=-1): return _raw_fft(a, n, axis, fftpack.rffti, fftpack.rfftf, _real_fft_cache) -def irefft(a, n=None, axis=-1): - """irefft(a, n=None, axis=-1) +def irfft(a, n=None, axis=-1): + """irfft(a, n=None, axis=-1) Will return the real valued n point inverse discrete Fourier transform of a, where a contains the nonnegative frequency terms of a Hermite-symmetric @@ -144,10 +145,10 @@ def irefft(a, n=None, axis=-1): If you specify an n such that a must be zero-padded or truncated, the extra/removed values will be added/removed at high frequencies. One can thus resample a series to m points via Fourier interpolation by: a_resamp - = irefft(refft(a), m). + = irfft(rfft(a), m). - This is the inverse of refft: - irefft(refft(a), len(a)) == a + This is the inverse of rfft: + irfft(rfft(a), len(a)) == a within numerical accuracy.""" a = asarray(a).astype(complex) @@ -161,7 +162,7 @@ def hfft(a, n=None, axis=-1): """hfft(a, n=None, axis=-1) ihfft(a, n=None, axis=-1) - These are a pair analogous to refft/irefft, but for the + These are a pair analogous to rfft/irfft, but for the opposite case: here the signal is real in the frequency domain and has Hermite symmetry in the time domain. So here it's hermite_fft for which you must supply the length of the result if it is to be odd. @@ -172,14 +173,14 @@ def hfft(a, n=None, axis=-1): a = asarray(a).astype(complex) if n == None: n = (shape(a)[axis] - 1) * 2 - return irefft(conjugate(a), n, axis) * n + return irfft(conjugate(a), n, axis) * n def ihfft(a, n=None, axis=-1): """hfft(a, n=None, axis=-1) ihfft(a, n=None, axis=-1) - These are a pair analogous to refft/irefft, but for the + These are a pair analogous to rfft/irfft, but for the opposite case: here the signal is real in the frequency domain and has Hermite symmetry in the time domain. So here it's hfft for which you must supply the length of the result if it is to be odd. @@ -190,7 +191,7 @@ def ihfft(a, n=None, axis=-1): a = asarray(a).astype(float) if n == None: n = shape(a)[axis] - return conjugate(refft(a, n, axis))/n + return conjugate(rfft(a, n, axis))/n def _cook_nd_args(a, s=None, axes=None, invreal=0): @@ -265,8 +266,8 @@ def ifft2(a, s=None, axes=(-2,-1)): return _raw_fftnd(a, s, axes, ifft) -def refftn(a, s=None, axes=None): - """refftn(a, s=None, axes=None) +def rfftn(a, s=None, axes=None): + """rfftn(a, s=None, axes=None) The n-dimensional discrete Fourier transform of a real array a. A real transform as real_fft is performed along the axis specified by the last @@ -275,24 +276,24 @@ def refftn(a, s=None, axes=None): a = asarray(a).astype(float) s, axes = _cook_nd_args(a, s, axes) - a = refft(a, s[-1], axes[-1]) + a = rfft(a, s[-1], axes[-1]) for ii in range(len(axes)-1): a = fft(a, s[ii], axes[ii]) return a -def refft2(a, s=None, axes=(-2,-1)): - """refft2(a, s=None, axes=(-2,-1)) +def rfft2(a, s=None, axes=(-2,-1)): + """rfft2(a, s=None, axes=(-2,-1)) - The 2d fft of the real valued array a. This is really just refftn with + The 2d fft of the real valued array a. This is really just rfftn with different default behavior.""" return real_fftnd(a, s, axes) -def irefftn(a, s=None, axes=None): - """irefftn(a, s=None, axes=None) +def irfftn(a, s=None, axes=None): + """irfftn(a, s=None, axes=None) - The inverse of refftn. The transform implemented in inverse_fft is + The inverse of rfftn. The transform implemented in inverse_fft is applied along all axes but the last, then the transform implemented in inverse_real_fft is performed along the last axis. As with inverse_real_fft, the length of the result along that axis must be @@ -302,14 +303,21 @@ def irefftn(a, s=None, axes=None): s, axes = _cook_nd_args(a, s, axes, invreal=1) for ii in range(len(axes)-1): a = ifft(a, s[ii], axes[ii]) - a = irefft(a, s[-1], axes[-1]) + a = irfft(a, s[-1], axes[-1]) return a -def irefft2(a, s=None, axes=(-2,-1)): - """irefft2(a, s=None, axes=(-2, -1)) +def irfft2(a, s=None, axes=(-2,-1)): + """irfft2(a, s=None, axes=(-2, -1)) - The inverse of refft2. This is really just irefftn with + The inverse of rfft2. This is really just irfftn with different default behavior.""" - return irefftn(a, s, axes) + return irfftn(a, s, axes) +# Deprecated names +refft = rfft +irefft = irfft +refft2 = rfft2 +irefft2 = irfft2 +refftn = rfftn +irefftn = irfftn |