|Subject:||Re: [Help-glpk] [Fwd: Help demand]|
|Date:||Mon, 11 Feb 2013 10:45:37 -0500|
-------- Forwarded Message --------
From: Alexandre Saidi <address@hidden>
To: glpk <address@hidden>
Cc: Alexandre Saidi <address@hidden>, Andrew Makhorin
Subject: Help demand
Date: Mon, 11 Feb 2013 10:14:48 +0100
I've been fighting some (few) quarters with the translation of the following constraint into GLPK.
If anybody can help with a working answer :
trying to translate efficiently the "element" CP constraint to GLPK, I've the following (simpler) constraints that i want to translate (but let's forget "element" for now) :
(binary_y = 1) <=> (X = Z and W = K) every thing is variable.
X,Z are bounded (1..60), W,K are also bounded (1..10, they are vector indices)
That's, if I ever have binary_y = 1, I want to put 2 pairs of variables equal. 'and' is a logical connector and '<=>' stands for 'equivalent' (double 'implies').
In fact, I'm working with a problem with 20000 variables and many many constraints. So the 'performance' is a critical issue.
I know that the 'element' constraint has been studied but those general solutions did not work (efficiently) for me.
A translation by the BigM method is welcome (apart from all cons of that method).
Maitre de Conférences
Ecole Centrale de Lyon-Dép. MI
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