Looks like Wolfram MathWorld would favor the docstring, but the possibility of a "use-domain" dependency seems plausible (after all, a similar dilemma is observed, e.g., w/ the Fourier Transform)--I guess one discipline's future is another discipline's past. :-)
http://mathworld.wolfram.com/Autocorrelation.html DG Date: Tue, 8 Oct 2013 20:10:41 +0100 > From: Richard Hattersley <rhatters...@gmail.com> > Subject: Re: [Numpy-discussion] Bug in numpy.correlate documentation > To: Discussion of Numerical Python <numpy-discussion@scipy.org> > Message-ID: > <CAP=RS9k54vtNFHy9ppG=U09oEHwB=KLV0xvwR6BfFgB3o5S= > f...@mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Bernard, > > Looks like you're on to something - two other people have raised this > discrepancy before: https://github.com/numpy/numpy/issues/2588. > Unfortunately, when it comes to resolving the discrepancy one of the > previous comments takes the opposite view. Namely, that the docstring is > correct and the code is wrong. > > Do different domains use different conventions here? Are there some > references to back up one stance or another? > > But all else being equal, I'm guessing there'll be far more appetite for > updating the documentation than the code. > > Regards, > Richard Hattersley > > > On 7 October 2013 22:09, Bernhard Spinnler <bernhard.spinn...@gmx.net > >wrote: > > > The numpy.correlate documentation says: > > > > correlate(a, v) = z[k] = sum_n a[n] * conj(v[n+k]) > > > <snip> > > [so] according to the documentation, z should be > > > > z[-1] = a[1] * conj(v[0]) = 4.+0.j > > z[0] = a[0] * conj(v[0]) + a[1] * conj(v[1]) = 2.-2.j > > z[1] = a[0] * conj(v[1]) = 0.-1.j > > > > which is the time reversed version of what correlate() calculates. >
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