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Re: Approximate convolution - for loop problem [message #64402 is a reply to message #64381]

Mon, 22 December 2008 01:31

Wout De Nolf
Messages: 194
Registered: October 2008

Senior Member

On Sun, 21 Dec 2008 09:32:40 -0800 (PST), samuel.leach@gmail.com
wrote:

> nsamp=n_elements(signal)
> const1 = exp(-tsamp/taubolo)
> const2 = 1.-const1
>
> bolo_signal = const2*signal
> for ii= 1L,nsamp-1L do begin
> bolo_signal[ii] += const1*bolo_signal[ii-1]
> endfor
>
> where tsamp and taubolo are scalars. Is there any way to avoid the for
> loop in this case? The hope is to speed up the execution.

This is without loop. Not sure it's faster though.

a=[1.,2.,3.,4.]
c=0.5
n=n_elements(a)

a=reform([reform(rebin([a,0],n+1,n-1,/sample),n*n-1),a[0]],n ,n)
i=REBIN(LINDGEN(n), n, n)
j=REBIN(TRANSPOSE(LINDGEN(n)), n, n)
a*= i ge j

c=rebin(c^reverse(indgen(n)),n,n,/sample)
a=reverse(total(a*c,1))
print,a

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[Message index]

		Re: Approximate convolution - for loop problem By: Sam on Mon, 22 December 2008 14:19
		Re: Approximate convolution - for loop problem By: Wout De Nolf on Mon, 22 December 2008 01:31
		Re: Approximate convolution - for loop problem By: David Fanning on Sun, 21 December 2008 12:44
		Re: Approximate convolution - for loop problem By: Sam on Sun, 21 December 2008 12:01
		Re: Approximate convolution - for loop problem By: David Fanning on Sun, 21 December 2008 10:03
		Re: Approximate convolution - for loop problem By: Jeremy Bailin on Tue, 23 December 2008 18:27
		Re: Approximate convolution - for loop problem By: andrews32940 on Tue, 23 December 2008 11:46

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