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Mon Apr 2 10:27:55 EDT 2001 · http://mail.python.org/pipermail/python-list/2001-April/100885.html

On Sat, 31 Mar 2001, Robert Amesz wrote:

> Konrad Hinsen wrote:
[...]
> >Except for zero-padding in case of non-periodic signals. That's why
> >I always recommend to look at a detailed description before doing
> >this; some of my colleagues keep telling me that FFT techniques "don't
> >work", and I suspect this is the reason.
>
> Well, why dont you/they try a different kind of integral transform,
> that might give a better result. Perhaps something like wavelets? Of
> course, a fast algorithm must be available to do the transform and its
> inverse but if there is it might be worth to do some experimenting.
[...]

He was just pointing out that it doesn't make sense to take a non-periodic
function, smear it out, and then expect there to be no end effects.  With
FFT convolution, for example, you end up smearing from 'the other end' of
your function, whether you like it or not.  You have to reckon on
calculating more of your function that you want to end up with, so you can
throw the wrongly smeared regions out.

Err, hope that's clear...  As Konrad says, this is explained properly in
many Numerical Analysis books.

John

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Gaussian line profile using numeric python