[Numpy-discussion] Problem with correlate

David Cournapeau david@ar.media.kyoto-u.ac...
Tue Jun 2 21:03:02 CDT 2009


Charles R Harris wrote:
>
>
>
>     I also think that having weighting options would be good.  I now
>     understand the complexities of the various
>     weightings that can be applied to the correlation i.e. biased vs
>     unbiased but I think that having correlate
>     include these options might prompt users to investigate which one
>     they really needed. Correlate seemed
>     so simple when I first used it but it took me ages to realise that
>     these are choices to be made.
>
>
> I wonder if xcorrelate would be a better name than acorrelate?

It may be confusing, because what acorrelate currently does is not what
xcorr does under matlab. Under matlab, xcorr computes the 1d cross
correlation column-wise (would be axis wise under numpy). If I get the
time today, I will try to implement a first version using generalized
ufunc - that would be a good occasion to learn generalized ufunc.

If that works well, maybe there is no need for the current acorrelate at
all (but we should still keep PyArray_Acorrelate, I think).

cheers,

David


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