CODEWITHSUNDEEP
cplex
FMontupet
FMontupet

Reputation: 1

CPLEX - Simple constraint that is not working

I'm quite new to CPLEX and I have an issue with one of my constraint.

I need to sum over only terms that respect a certain condition :

Sum

I first wrote

forall(r in RangeR, w in RangeW, d in RangeD, h in RangeH){
        sum(k in RangeK) sum(j in RangeJ) rc[j][r] * sum(g in max(0,h-p[j]+1)..h) x[k][j][w][d][g] <= ra[r][w][d][h];   
}

Of course, that made me get the classical "cannot extract expression" error. I tried to by-pass this error by writing the constraint differently :

forall(r in RangeR, w in RangeW, d in RangeD, h in RangeH){        
    sum(k in RangeK) sum(j in RangeJ) rc[j][r]*sum (g in RangeH)(g >= h - p[j]+1 && g <= h)*x[k][j][w][d][g] <= ra[r][w][d][h];    
}

If I understood correctly, the expression between brackets should count every time the condition is true.

With this reformulation, I no longer have the "cannot extract expression" error (in fact I no longer have errors), but the constraint is not considered in the solution.

How do I make this constraint count in the solving ?

Thanks !

Upvotes: 0

Views: 112

Answers (1)

ddotsdot
ddotsdot

Reputation: 303

Please check if you still get a "cannot extract expression" error when you replace sum(g in max(0,h-p[j]+1)..h) by sum(g in max(1,h-p[j]+1)..h) because in your mathematical formulation there is a >0 restriction imposed on the summation index.

Upvotes: 0

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