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Re: fast convolving question [message #60625 is a reply to message #60624]

Fri, 30 May 2008 00:44

rogass
Messages: 200
Registered: April 2008

Senior Member

On May 29, 9:47 pm, Chris <cnb4s...@gmail.com> wrote:
>> But, did you see the error, why:
>
>> else (conv)[(i=indarray2[0:sm-1])]=kernel##mat( indsmall+ind(i) )
>
>> only works for the first ind(i=0) and then repeats it by using always
>> ind(0) instead of ind(i)?
>
>> It this a bug or error in code?
>
> Both kernel and mat(indsmall+ind(i)) are vectors of length sm. When
> you matrix multiply them, the answer is single number. So you are just
> asking to fill in conv with the same number at every element given by
> i.

Ah, ok - THANKS. But how can I fix this?

If I would:

(conv)[(i=0)]=kernel##mat( indsmall+ind(i) ) ->result right
(conv)[(i=1)]=kernel##mat( indsmall+ind(i) ) ->result right
and so on..

But if I would:

(conv)[(i=indarray2[0:sm-1])]=kernel##mat( indsmall+ind(i) )

or

(conv)[(i=indgen(sm))])]=kernel##mat( indsmall+ind(i) )

then it does what you said. That makes no sense to me. How can I do it
parallel for all indices given by i?

If the code would work, its 100 times faster than fft - and that is
the aim.

Please help again.

Thanks and best regards

Christian

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[Message index]

		Re: fast convolving question By: Chris[5] on Fri, 30 May 2008 13:06
		Re: fast convolving question By: rogass on Fri, 30 May 2008 05:44
		Re: fast convolving question By: Chris[5] on Fri, 30 May 2008 03:15
		Re: fast convolving question By: rogass on Fri, 30 May 2008 00:44
		Re: fast convolving question By: Chris[5] on Thu, 29 May 2008 12:47
		Re: fast convolving question By: rogass on Thu, 29 May 2008 04:38
		Re: fast convolving question By: Chris[5] on Thu, 29 May 2008 02:41
		Re: fast convolving question By: rogass on Mon, 09 June 2008 08:39

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