Originally posted by: bobby76

Hello all,

Suppose I have a double array decision variables, i.e

int njobs = 2;

range jobs = 1..njobs;

dvar int+ c[i in jobs][j in jobs];

Now the numbers of decision variable c is the combination of njobs, i.e. 4, which are c[1][1], c[1][2], c[2][1], c[2][2]. 

I want to limit the number of c, i.e., adding the condition such that i != j. So the desired decision varibles will be c[1][2], c[2][1].

How to declare that in dvar declaration?

Thank you

One way to do this is to index with a 2-dimensional tuple:

tuple ij { int i; int j; }                            // A pair of jobs
{ij} ijs = { <i,j> | i in jobs, j in jobs : i != j }; // All pairs of different jobs
dvar int+ c[ijs];

Originally posted by: bobby76

Thank you for your answer.