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Re: [Help-glpk] Feature request: branching priority and direction
From: |
Andrew Makhorin |
Subject: |
Re: [Help-glpk] Feature request: branching priority and direction |
Date: |
Thu, 13 Sep 2007 09:42:14 +0400 |
> Solution speed for many MIPs can be improved by controlling
> branching. Unfortunately in MathProg there is no syntax provided to
> do so, leaving only programming as an option.
> ILOG OPL offers the following syntax to control branching:
> for(var j in Columns) {
> x[j].priority = c[j]/maxCoef[j];
> x[j].direction = "BranchDown";
> }
> The same is supported by AMPL as described in
> http://www.ampl.com/NEW/suffixes.html.
> I think this could be added to GLPK with limited effort.
> Priority should be of type float. The branching algorithm should
> only choose between unfixed integers with the highest priority.
> Direction could be an integer in {-1, 0, 1}:
> -1 = branch down,
> 0 = branch direction to be chosen by the branching algorithm,
> 1 = branch up).
Thank you for your suggestion.