CODEWITHSUNDEEP
conditional-statementscplex
Wannes Gillis
Wannes Gillis

Reputation: 1

Conditional if sum

I want to sum over a range (Areas) except if j is not equal to k. Can anybody help me?

I tried:

forall( k in Areas ) 
        sum ( j in Areas: j!=k ) X[k][j] == 1;
Also tried:
forall( k in Areas ) 
        sum ( j in Areas) (j!=k)*X[k][j] == 1;

    int NbAreas = 5;

    range Areas = 1..NbAreas;

    float P[Areas] = [0, 0.3, 0.65, 0.2, 0.1];
    float D[Areas] = [0, 7, 5, 3, 9];
    float FROMTO[Areas][Areas] =    [ 
                                    [0, 2, 5, 1, 3],
                                    [2, 0, 4, 3, 8],
                                    [5, 4, 0, 6, 2],
                                    [1, 3, 6, 0, 7],
                                    [3, 8, 2, 7, 0]];


    dvar int Y[Areas];
    dvar int T[Areas];
    dvar int X[Areas][Areas] in 0..1;


    maximize sum( i in Areas ) P[i] * Y[i];
    subject to {
        forall( k in Areas ) 
            sum ( j in Areas: j!=k) X[k][j] == 1;
        forall( k in Areas)
            sum ( i in Areas: i!=k) X[i][k] == 1;
        forall( i in Areas) forall (j in Areas) T[i] + FROMTO[i][j] -     T[j] - 100*(1-X[i][j]) <= 0;
        T[1] == 0;
        forall( i in Areas: i!=1) T[i] - D[i] - 1000*(1-Y[i]) <= 0;
}

Upvotes: 0

Views: 144

Answers (2)

Alex Fleischer
Alex Fleischer

Reputation: 10059

You wrote "except if j is not equal to k".

So instead of

forall( k in Areas)
        sum ( i in Areas: i!=k) X[i][k] == 1;

I would write

forall( k in Areas)
        sum ( i in Areas: i==k) X[i][k] == 1;

Upvotes: 0

Daniel Junglas
Daniel Junglas

Reputation: 5930

I take it you meant

I want to sum over a range (Areas) except if j is equal (instead of "not equal") to k.

I also assume that your issue is that the model you posted is infeasible. You should label your constraints so that the conflict refiner can run and then look at the results of the conflict refiner. If I label your constraints like so:

maximize sum( i in Areas ) P[i] * Y[i];
subject to {
    forall( k in Areas ) 
        sum1: sum ( j in Areas: j!=k) X[k][j] == 1;
    forall( k in Areas)
        sum2: sum ( i in Areas: i!=k) X[i][k] == 1;
    forall( i in Areas) forall (j in Areas)
        fromto: T[i] + FROMTO[i][j] - T[j] - 100*(1-X[i][j]) <= 0;
    T[1] == 0;
    forall( i in Areas: i!=1)
        limit: T[i] - D[i] - 1000*(1-Y[i]) <= 0;

Then I get this conflict:

 sum1(1):      X(1)(2) + X(1)(3) + X(1)(4) + X(1)(5)  = 1
 sum1(2):      X(2)(1) + X(2)(3) + X(2)(4) + X(2)(5)  = 1
 sum1(3):      X(3)(1) + X(3)(2) + X(3)(4) + X(3)(5)  = 1
 sum1(4):      X(4)(1) + X(4)(2) + X(4)(3) + X(4)(5)  = 1
 sum1(5):      X(5)(1) + X(5)(2) + X(5)(3) + X(5)(4)  = 1
 fromto(1)(2): 100 X(1)(2) + T(1) - T(2) <= 98
 fromto(1)(3): 100 X(1)(3) + T(1) - T(3) <= 95
 fromto(1)(4): 100 X(1)(4) + T(1) - T(4) <= 99
 fromto(1)(5): 100 X(1)(5) + T(1) - T(5) <= 97
 fromto(2)(1): 100 X(2)(1) - T(1) + T(2) <= 98
 fromto(2)(3): 100 X(2)(3) + T(2) - T(3) <= 96
 fromto(2)(4): 100 X(2)(4) + T(2) - T(4) <= 97
 fromto(2)(5): 100 X(2)(5) + T(2) - T(5) <= 92
 fromto(3)(1): 100 X(3)(1) - T(1) + T(3) <= 95
 fromto(3)(2): 100 X(3)(2) - T(2) + T(3) <= 96
 fromto(3)(4): 100 X(3)(4) + T(3) - T(4) <= 94
 fromto(3)(5): 100 X(3)(5) + T(3) - T(5) <= 98
 fromto(4)(1): 100 X(4)(1) - T(1) + T(4) <= 99
 fromto(4)(2): 100 X(4)(2) - T(2) + T(4) <= 97
 fromto(4)(3): 100 X(4)(3) - T(3) + T(4) <= 94
 fromto(4)(5): 100 X(4)(5) + T(4) - T(5) <= 93
 fromto(5)(1): 100 X(5)(1) - T(1) + T(5) <= 97
 fromto(5)(2): 100 X(5)(2) - T(2) + T(5) <= 92
 fromto(5)(3): 100 X(5)(3) - T(3) + T(5) <= 98
 fromto(5)(4): 100 X(5)(4) - T(4) + T(5) <= 93

So it seems your data in FROMTO and T does not allow a feasible solution.

Upvotes: 1

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