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Re: [Help-glpk] operand has invalid type
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From: |
Oscar Gustafsson |
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Subject: |
Re: [Help-glpk] operand has invalid type |
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Date: |
Tue, 23 Oct 2007 08:54:59 +0200 (MEST) |
On Mon, 22 Oct 2007, Leonard, Tim wrote:
I'm getting "operand following / has invalid type" on line 9
(Hardness[p]/Speed[a]) of this program. I confess to being baffled by
the rules about vars and params. Would you be so kind as to try to
explain.
var Speed {Algorithm} >= 0;
var Hardness {Problem} >= 0;
param MeasuredTime {p in Problem, a in Algorithm};
param PredictedTime {p in Problem, a in Algorithm} :=
Hardness[p] / Speed[a];
Both Hardness and Speed are variables and GLPK is a linear programming
kit, so this type of non-linear formulation can not be used. Also a param
can only be defined from other parameters, so if Speed and Hardness were
paramteters this would be totally valid.
/Oscar