Cplex Java多维决策变量，最小化

Question

I'm using Cplex in Java and want to minimize the sum of the products of elements from two matrices (products of elements with the same index).

x[n][n] contains decisionvariables [0, 1]

cost[n][n] contains the cost for the way from i to j

I want to minimize the sum of costs x[i][j] * j[i][j] for all i..n; j..n.

I created the variables like this:

[...]
static double   lb = 0.0;
static double   ub = 1.0;
static double   cost[][] = new double[n][n];

IloNumVar[][] x = new IloNumVar[n][n];
        for(int i=0; i<n; i++){
            for(int j=0; j<n; j++){
                x[i][j] = cplex.numVar(lb, ub);
                }
        }

My Problem is that I don't know how to create the minimize part.

I found something that seems to be very similar to my problem ( Cplex c++ multidimensional decision variable ) but as I am not familiar to c++, I don't get any solution out of it.

Answer 1

This should do it:

IloLinearNumExpr obj = cplex.linearNumExpr();

for (int i = 0; i < n; i++) {
  for (int j = 0; j < n; j++) {
    obj.addTerm(cost[i][j], x[i][j]);
  }
}

cplex.addMinimize(obj);