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Re: [Help-glpk] order restrictions
From: |
glpk xypron |
Subject: |
Re: [Help-glpk] order restrictions |
Date: |
Thu, 01 Nov 2012 07:44:20 +0100 |
Hello Robin,
> I have a MIP, very similar to the sudoku.mod example in the examples/
> directory.
MIP optimzers are not fast solvers for constraint programming problems.
To choose the variable glpsol uses the Tomlin-Driebeek heuristic by default, cf.
http://opim.wharton.upenn.edu/~guignard/916_2011/papers_to_read/Driebeck_1966_MSc.pdf
and
* Tomlin J.A. Branch and bound methods for integer and non-convex
* programming, in J.Abadie (ed.), Integer and Nonlinear Programming,
* North-Holland, Amsterdam, pp. 437-50 (1970).
You can influence the branching variable if you use GLPK library and provide a
callback function. See
gpk-4.47/doc/glpk.pdf
Best regards
Xypron
-------- Original-Nachricht --------
> Datum: Thu, 1 Nov 2012 11:20:24 +1300
> Von: robin hankin <address@hidden>
> An: address@hidden
> Betreff: [Help-glpk] order restrictions
> hello.
>
> I have a MIP, very similar to the sudoku.mod example in the examples/
> directory.
>
> It's a 3D binary array.
>
> Let's say I have three restrictions, A, B, and C.
>
> A is satisfied 70% of the time and it takes a long long time to evaluate.
> B is very similar to A but is satisfied 80% of the time.
> C is satisfied 0.0001% of the time and is very very quick.
>
> A human would ignore A and B, and concentrate on C. When he found a
> proposed solution
> that satisfies C, he would then check A and B (and if either of these is
> not satisfied he would
> go back to trawling through C).'
>
>
> How do I tell glpsol this information about the best order to evaluate
> A/B/C? Or does it "know"?
>
>
>
>
>
>
> --
> Robin Hankin
> Uncertainty Analyst
> address@hidden
- Re: [Help-glpk] order restrictions,
glpk xypron <=