
From:  Michael Bramley 
Subject:  [Helpglpk] glpsol.exe differs from AMPL 
Date:  Wed, 27 Jun 2012 17:10:47 0400 
Hello: I am running glpk MIP and in AMPL and
finding that the order of the solutions differ. For example, say I have a
model where I need to maximize an objective based upon paired values X, Y, and
Z (and each pairing has a score). I am not using any additional options for
the solutions, eg specifying branch&cut, etc. AMPL will tell me that the solution is X,
Y, Z glpk will tell me the solution is Z, X, Y. I note that the sum of the scores for each
solution is equivalent (as it should be as addition is commutative). The problem I am trying to reconcile is is
there a physical difference between ordering objects X, then Y, then Z with the
order of Z, then X, then Y? Not sure if this is clear to everyone, but
the main point is I see differences. Michael Bramley If you have received this message in error you should delete it from your system immediately and advise the sender. dunnhumby may monitor and record all emails. The views expressed in this email are those of the sender and not those of dunnhumby. 
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