Re: [Help-glpk] GMPL fails on circular references

[Andrew Makhorin]

> 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.