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## Re: [Help-glpk] Syntax error in Glpk modelling

**From**: |
Andrew Makhorin |

**Subject**: |
Re: [Help-glpk] Syntax error in Glpk modelling |

**Date**: |
Tue, 19 Mar 2013 03:03:53 +0400 |

On Tue, 2013-03-19 at 00:45 +0200, Figen Güngör wrote:
>* Can you please look at my question at Stackoverflow?*
>* http://stackoverflow.com/questions/15488041/syntax-error-in-linear-programming-modelling-with-glpk?noredirect=1#comment21925482_15488041*
>* var po := sum{i in I} c[i]*x[i];*
>* *
>* var cost := sum{i in I} a[i]*y[i] + b[i]*x[i];*
>* I am getting this syntax error:*
>* *
>* problem.mod:21: syntax error in variable statement *
>* Context: ...I } ; param d { i in I } ; var x { i in I } >= 0 ; var po :=*
>* MathProg model processing error*
>* *
>* Can you please help me out?*
>* *
In MathProg you cannot assign a value to a variable.
If you need to fix a variable at some value, you need to use appropriate
equality constraint, e.g.
var po;
s.t. foo: po = sum{i in I} c[i]*x[i];
var cost;
s.t. bar: cost = sum{i in I} a[i]*y[i] + b[i]*x[i];

**Re: [Help-glpk] Syntax error in Glpk modelling**,
*Andrew Makhorin* **<=**