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[Help-glpk] Constraints depending on the data section
From: |
Patrick Meyer |
Subject: |
[Help-glpk] Constraints depending on the data section |
Date: |
Thu, 19 Jul 2007 17:02:39 +0200 |
User-agent: |
Thunderbird 1.5.0.12 (X11/20070604) |
Hi,
Part of my problem looks as follows:
set X;
var stilde{j in X, k in X} >=-1, <=1;
where the variable stilde is constrained by a few conditions in the
problem.
Depending on the data section, I want to add some more constraints,
which I don't know how to express.
Imagine that in the data section I have:
set X := a b c d;
I would now like to express somehow in a constraint that
stilde[a,b] >= delta;
stilde[a,c] >= delta;
where delta is a parameter. Note that depending on the problem, these
constraints could involve different pairs of elements of X. That is why
they have to be defined in the data section.
I thought that I could add a parameter
param stildeConstraint : 1 2 :=
1 a b
2 a c ;
in the data section to express this, and write in the constraints section:
s.t. constOutranking{i in 1..2}: stilde[stildeConstraint[i,1],
stildeConstraint[i,2]] >= delta;
Nevertheless, this does not seem to be appropriate.
I receive as an error:
"stildeConstraint requires numeric data"
Does anybody know how this can be done in a more correct way ?
Thanx for any suggestion,
Patrick
- [Help-glpk] Constraints depending on the data section,
Patrick Meyer <=