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Re: How to speed up large FOR loops? [message #79812 is a reply to message #79811]

Tue, 10 April 2012 09:17

Fabzi
Messages: 305
Registered: July 2010

Senior Member

Hi,

Do you concatenate arrays in your loop?

e.g: out = [out, tmp]

On 04/10/2012 05:48 PM, Saurav Dhital wrote:
> Hi,
>
> By necessity, I have to use a long FOR loop (N>~ 300,000). I have
> made the operations inside the loop efficient enough that the first
> 40,000 iterations are relatively fast (~30 mins). Then it slows down
> to a crawl, with the entire process taking>24 hours. I would
> appreciate any advice how to speed this up.
>
> The operation inside the loop involves matching between two (large)
> FITS files and assigning the matches to another (previously created)
> FITS structure. There are no new variable created per iteration, so
> there should be no memory being used (each loop writes over the
> variables anyways). I even create small substructures (e.g.,>
> sub_mystruct = mystruct[0:10]) so that I don't have to index the large
> structures.
>
> Any tip or advice would be much appreciated,
> ~Saurav

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[Message index]

		Re: How to speed up large FOR loops? By: Saurav Dhital on Tue, 10 April 2012 12:39
		Re: How to speed up large FOR loops? By: Craig Markwardt on Tue, 10 April 2012 11:21
		Re: How to speed up large FOR loops? By: Saurav Dhital on Tue, 10 April 2012 10:23
		Re: How to speed up large FOR loops? By: David Fanning on Tue, 10 April 2012 10:13
		Re: How to speed up large FOR loops? By: Fabzi on Tue, 10 April 2012 09:53
		Re: How to speed up large FOR loops? By: Saurav Dhital on Tue, 10 April 2012 09:26
		Re: How to speed up large FOR loops? By: Fabzi on Tue, 10 April 2012 09:17
		Re: How to speed up large FOR loops? By: Matt Francis on Thu, 12 April 2012 19:41
		Re: How to speed up large FOR loops? By: Saurav on Fri, 20 April 2012 09:48

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