[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Fast matrix filling in IDL

> Hopefully everyone is running this a few times and noting when
> the times have become "stable". Here are three sequential runs
> on a Sun Sparc 2 (IDL 5.1):
> IDL> test
> Time for Loop:        2.7740721
> Time for Matrix Operations:        5.2337180     ; OUT OF WHACK!
> Time for Rebin Operations:       0.16969705
> IDL> test
> Time for Loop:        2.6756930
> Time for Matrix Operations:       0.27333605
> Time for Rebin Operations:       0.16920698
> IDL> test
> Time for Loop:        2.7509290
> Time for Matrix Operations:       0.27153599
> Time for Rebin Operations:       0.16843796

Perhaps the first one is not out of whack, but rather, the accurate
When the test is being performed a second time, the operating system has 
information that is cached, thus avoiding doing part of the work
associated with the task.  Particularly in big tests, I often  notice
speed-ups each time, for the first few times I test something.  I like
to test by completely exiting my environment, doing other things, and
coming back and repeating the test.  If I'm feeling hard-core about it,
I do a reboot in between.

David Ritscher

Cardiac Rhythm Management Laboratory
Department of Medicine
University of Alabama at Birmingham
B168 Volker Hall  -  1670 University Boulevard
Birmingham  AL  35294-0019
Tel: (205) 975-2122      Fax:   (205) 975-4720
Email: david.ritscher@bigfoot.com