Mod operator for scalar product

[Saurabh Potdar]

Available operators for scalar are "=", ">=", "<="

model.scalar(variable, coeff, "=", target).post();

Now I'm trying to add the following constraint

scalar product of  variable * coeff %10 == 0.

So how to do this?

[Saurabh Potdar]

Model model = new Model("");
int[] duration = new int[]{1, 2, 1, 2, 3, 4, 1, 2};
int[] marks = new int[]{10, 5, 1, 5, 3, 4, 1, 2};
int targetDuration = 5;

IntVar[] questionSelectedOrNot = model.intVarArray("a", 8, 0, 1);

model.scalar(questionSelectedOrNot, duration, "=", targetDuration).post();
//Add a new constraint to model
// scalar product of questionSelectedOrNot and marks is a multiple of 10

if (model.getSolver().solve()) {
        System.out.println(questionSelectedOrNot);
}

[Arthur Godet]

Hi,

Sorry for the late answer, the mail notifications from the Google group were in my spam filter.

In Choco Solver, the modulo constraint is called mod, and you can call it from the model. To add the constraint you want, you will need an intermediate variable, let's call it scalarProduct :

IntVar scalarProduct = model.intVar(0, 31); // 31 being the maximum value of the scalar product you want

model.scalar(questionSelectedOrNot, marks, "=", scalarProduct).post();

model.mod(scalarProduct, 10, 0).post();

Have a nice day,
Arthur Godet