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Re: [Help-glpk] inf as RHS of constraint
From: |
Xypron |
Subject: |
Re: [Help-glpk] inf as RHS of constraint |
Date: |
Tue, 18 Jan 2011 08:08:21 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.16) Gecko/20101123 SeaMonkey/2.0.11 |
Hello Kevin,
if the right hand side is infinity the constraint is not really needed.
Which version of GLPK have you been using? GLPK 4.45 should support inf
and infinity.
Best regards
Xypron
Kevin Hunter wrote:
Hullo List,
I've recently created an LP that file that both CPlex and Gurobi
accept and solve, but that GLPK does not (LP file attached). The
issue is the use of infinity ('inf') on the right-hand side of a
constraint.
Judging from the grammar in the comments above 'parse_constraints' in
glpcpx.c, it would appear that GLPK does not support it. Should I
consider this a bug? Or is there perhaps a better way I should be
writing these constraints?
Thanks,
Kevin
P.S. The ironic thing is that the only place that I can find a
thorough grammar for the *CPLEX* LP format is within the GLPK
project. Kudos to GLPK for quality code backed by an actual grammar!