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Re: [Help-glpk] GMPL fails on circular references
From: |
Andrew Makhorin |
Subject: |
Re: [Help-glpk] GMPL fails on circular references |
Date: |
Sat, 21 Jun 2008 11:31:42 +0400 |
>> I had a line of math-prog code that had a circular reference:
>> param FromNode{ (train,sd,seq) in TRAIN_SEGS } symbolic
>> := Terminal[FromNode[train,sd,seq]];
>> GMPL, much further down in the model, just stops without any
>> warning or anything else. It took a while to figure out the circular
>> reference
>> and fix my error. If possible, it would be nice if GMPL could
>> discover this
>> and issue a message.
> It is problematic, because mathprog allows recursive definition of
> sets and parameters. Incorrect definition, as in your case, leads to
> infinite loop that, in turn, causes stack overflow--the same that
> would happen in any programming language.
See, for example, recursive definition of parameter z in model bpp.mod
included in glpk distribution.