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Re: [Help-glpk] [Fwd: Scaling: Which? and Suppressing output]
From: |
glpk xypron |
Subject: |
Re: [Help-glpk] [Fwd: Scaling: Which? and Suppressing output] |
Date: |
Thu, 24 Feb 2011 23:15:58 +0100 |
> Any suggestions on which scaling method might be preferred for my
> application? I think what is happening is that some of the
> coefficients are for all practical purposes effectively 0. These
> "effective zeroes" are being represented in the matrix as some very
> small number, e.g. 7.2134e-32, whereas the other entries are of a
> common everyday size like 8.2, or 0.34. Which scaling method would be
> preferred for handling this situation?
>
> -- Glenn
Hello Glenn,
I added a page to the wikibook:
http://en.wikibooks.org/wiki/GLPK/Scaling
If some very small coefficients (e.g. 7.2134e-32) can safely be replaced
by zero do not enter them into the matrix at all.
I would suggest GLP_SF_AUTO as a starting point for scaling. If all
coefficients are between .1 and 10, scaling will be skipped by this
setting.
Best regards
Xypron
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