Originally posted by: bebulo

I see that ILOSIMPLEXCALLBACK is called at end of each iteration. I can access the status and objective value in the callback, but how can I access the current solution?

edit:

static ILOBARRIERCALLBACK2(MyCallback, IloCplex, cplex, IloNumVarArray, x) {
    cout << "Iteration " << getNiterations() << ": ";
    if (isFeasible()) {
        cout << "Objective = " << getObjValue() << endl;
        //cout << "x[0] = " << (float)cplex.getValue(x[0]) << endl;  

        //Concert exception caught: CPLEX Error  1217: No solution exists.
    }
    else {
        cout << "Infeasibility measure = " << getInfeasibility() << endl;
    }
}

Originally posted by: RWunderling

This information is not available from within a callback.  In general, only the methods of the callback classes can be used within a callback, but not the methods of the cplex object currently being optimized.

You can, however, set an iteration limit of 1 and call the Simplex optimizer from within a loop.  Note, that this will not reproduce the same solution path as calling Simplex without limit and performance will suffer.

Roland