Re: [Help-glpk] Strange Error with if/then/else

[Jonathan Klein]

> This assumes that Student_Choice[i,j] is not a variable, among other things.
> There is no logical reason why variables can't appear in if-expressions or
> in subscripts, it's just that not all modeling languages have evolved to
> handle these possibilities.
>
> Bob Fourer
> address@hidden

I think, that i know now, why it is impossible to have varaibles in
if-expressions.
All the parameters of a problem are static and wont change during
calculation. So if you load an MathProg Problem, it is translated into
conditions for glpk. During "compilation" the proramm can decide the
result of an if-expression, but glpk itself has no support for if
expressions.
For me, this makes sense and is absolutly logical.

Jonathan Klein