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Re: Fast matrix filling in IDL [message #13789 is a reply to message #13788]

Sat, 12 December 1998 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Stein Vidar Hagfors Haugan (steinhh@ulrik.uio.no) writes:
>
> A slight modification of David's program, and adding
> my favourite speedup method:
>
> time = systime(1)
> array = rebin(reform(v,m,1,/overwrite),m,n,/sample)
> print, 'Time for Rebin Operations: ', systime(1) - time
>
> On { alpha OSF unix 5.2 Oct 30 1998}, this gives:
>
> Time for Loop: 0.27343702
> Time for Matrix Operations: 0.093750000
> Time for Rebin Operations: 0.067382932
>
> Note that the relative speeds can vary quite a lot on
> different architectures.

I guess. Here is what I get with Stein Vidar's modifications
on my Windows NT machine:

IDL> Print, !Version
{ x86 Win32 Windows 5.2 Oct 30 1998}
IDL> test
Time for Loop: 0.10000002
Time for Matrix Operations: 0.019999981
Time for Rebin Operations: 0.039999962

The Rebin operations are twice as slow as the matric operations.
Hummm. Why!?

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Progamming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: Fast matrix filling in IDL By: Kevin Ivory on Mon, 14 December 1998 00:00
		Re: Fast matrix filling in IDL By: steinhh on Mon, 14 December 1998 00:00
		Re: Fast matrix filling in IDL By: davidf on Mon, 14 December 1998 00:00
		Re: Fast matrix filling in IDL By: Kevin Ivory on Mon, 14 December 1998 00:00
		Re: Fast matrix filling in IDL By: Phillip & Suzanne on Sat, 12 December 1998 00:00
		Re: Fast matrix filling in IDL By: davidf on Sat, 12 December 1998 00:00
		Re: Fast matrix filling in IDL By: steinhh on Sat, 12 December 1998 00:00
		Re: Fast matrix filling in IDL By: davidf on Fri, 11 December 1998 00:00

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