On Mon, Jul 12, 2010 at 3:04 PM, Eric Firing <[email protected]> wrote:
> On 07/12/2010 11:43 AM, David Goldsmith wrote: > > >From the docstring: > > > > "A[0] contains the zero-frequency term (the mean of the signal)" > > > > And yet, consistent w/ the definition given in the docstring (and > > included w/ an earlier email), the code gives, e.g.: > > > > >>> import numpy as np > > >>> x = np.ones((16,)); x > > array([ 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., > > 1., 1., 1.]) > > >>> y = np.fft.fft(x); y > > array([ 16.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, > > 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j, > > 0.+0.j, 0.+0.j, 0.+0.j, 0.+0.j]) > > > > i.e., the zero-th term is the sum, not the mean (which, again, is > > consistent w/ the stated defining formula). > > > > So, same ol', same ol': bug in the doc (presumably) or bug in the code? > > Bug in the doc. Good catch. Thanks. (In case you hadn't noticed, I'm detail-oriented to a fault.) :-/ DG > "mean" is correct for the ifft, not for > the fft. > > Eric > > > > > DG > > > > > > > > _______________________________________________ > > NumPy-Discussion mailing list > > [email protected] > > http://mail.scipy.org/mailman/listinfo/numpy-discussion > > _______________________________________________ > NumPy-Discussion mailing list > [email protected] > http://mail.scipy.org/mailman/listinfo/numpy-discussion > -- Mathematician: noun, someone who disavows certainty when their uncertainty set is non-empty, even if that set has measure zero. Hope: noun, that delusive spirit which escaped Pandora's jar and, with her lies, prevents mankind from committing a general suicide. (As interpreted by Robert Graves)
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