Error running the example from Documentation

[Anonymous]

I'm running Choco 2.1.5. I tried out the example on page 24 of the official Documentation.

public static void main(String[] args) throws Exception {
        ChocoLogging.toSearch();
        Model m = new CPModel();
        IntegerVariable x = makeIntVar("x", 1, 100);
        IntegerVariable y = makeIntVar("y", 1, 100);
        IntegerVariable z = makeIntVar("z", 1, 100);
        IntegerVariable a = makeIntVar("a", 1, 100);
        IntegerVariable b = makeIntVar("b", 1, 100);
        IntegerVariable c = makeIntVar("c", 1, 100);
        m.addConstraint(ifOnlyIf(or(eq(x, mult(10, abs(y))), leq(z, 9)),
                allDifferent(a, b, c)));
        Solver s = new CPSolver();
        s.read(m);
        if (s.solve()) {
            System.out.println("***Solution");
            System.out.println(s.solutionToString());
        } else {
            System.out.println("***No solution");
        }
    }

It throws an exception.

Exception in thread "main" java.lang.UnsupportedOperationException
at choco.kernel.solver.constraints.AbstractSConstraint.opposite(AbstractSConstraint.java:270)
at choco.cp.solver.constraints.reified.ReifiedFactory.builder(ReifiedFactory.java:59)
at choco.cp.solver.constraints.reified.leaves.ConstraintLeaf.extractResult(ConstraintLeaf.java:85)
at choco.cp.solver.constraints.reified.leaves.bool.NotNode.extractResult(NotNode.java:58)
at choco.cp.solver.constraints.reified.leaves.bool.OrNode.extractResult(OrNode.java:67)
at choco.cp.solver.constraints.reified.leaves.bool.AndNode.extractConstraint(AndNode.java:86)
at choco.cp.solver.constraints.reified.ExpressionSConstraint.getDecomposition(ExpressionSConstraint.java:281)
at choco.cp.solver.CPSolver.decisionOnExpression(CPSolver.java:1966)
at choco.cp.solver.CPSolver.post(CPSolver.java:1895)
at choco.cp.solver.CPSolver.post(CPSolver.java:1931)
at choco.cp.solver.CPModelToCPSolver.readConstraints(CPModelToCPSolver.java:296)
at choco.cp.solver.CPSolver.read(CPSolver.java:519)
at org.clafer.Test.main(Test.java:85)

I'm also having trouble with the ifThenElse constraint. Both of the following examples should have solutions but Choco cannot find any solutions.

public static void main(String[] args) throws Exception {
        ChocoLogging.toSearch();
        Model m = new CPModel();
        SetVariable x = makeSetVar("x", 1, 10);
        m.addConstraint(ifThenElse(TRUE, eqCard(x, 0), leqCard(x, 1)));
        Solver s = new CPSolver();
        s.read(m);
        if (s.solve()) {
            System.out.println("***Solution");
            System.out.println(s.solutionToString());
        } else {
            System.out.println("***No solution");
        }
    }

public static void main(String[] args) throws Exception {
        ChocoLogging.toSearch();
        Model m = new CPModel();
        SetVariable x = makeSetVar("x", 1, 10);
        IntegerVariable i = makeBooleanVar("i");
        m.addConstraint(ifThenElse(eq(i, 1), eqCard(x, 1), eqCard(x, 1)));
        
        Solver s = new CPSolver();
        s.read(m);
        if (s.solve()) {
            System.out.println("***Solution");
            System.out.println(s.solutionToString());
        } else {
            System.out.println("***No solution");
        }
    }

[Charles Prud'homme]

Hi,

Thank you for reporting the bug, the following instruction is missing:

m.setDefaultExpressionDecomposition(false);

Hope it helps,
CP

[Anonymous]

If I make a slight modification to the constraint, it fails with the same error. Even with setDefaultExpressionDecomposition set to false. I'm generating lots of the choco constraints programmatically and it feels very brittle.

ChocoLogging.toSearch();
        
        Model m = new CPModel();
        m.setDefaultExpressionDecomposition(false);
        SetVariable x = makeSetVar("x", 1, 100);
        IntegerVariable a = makeIntVar("a", 1, 100);
        IntegerVariable b = makeIntVar("b", 1, 100);
        IntegerVariable c = makeIntVar("c", 1, 100);
        m.addConstraint(ifOnlyIf(eqCard(x, 0),
                allDifferent(a, b, c)));
        Solver s = new CPSolver();
        s.read(m);
        if (s.solve()) {
            System.out.println("***Solution");
            System.out.println(s.solutionToString());
        } else {
            System.out.println("***No solution");
        }

Also, anything about the ifOnlyIf failing in the original post?

Thanks!