[Choco-users] Choco.mult takes a long time for "large" domains

[Joost G. <jpt...@gm...>]

Hello,

I have the following CSP :
	- three integer variables:  v1, v2, v3 (all with a domain of 0..1000)
	- one constraint: v1 = v2 * v3. 

Solving this in Choco 2.1.1 takes about 30871ms on my (admittedly oldish) macbook. It is a lot longer than i expected. Any explanation for this? Find my code below. 

many thanks!
Joost Geurts

	public Test() {
		System.out.println("start test");
		CPModel model = new CPModel();
		Solver solver = new CPSolver();
		
		//int max = 100 // finds a solution in 37ms
		int max = 1000; // 30871ms
		
		IntegerVariable v1 = Choco.makeIntVar("v1", 0, max);
		IntegerVariable v2 = Choco.makeIntVar("v2", 0, max);
		IntegerVariable v3 = Choco.makeIntVar("v3", 0, max);
		model.addVariable(v1);
		model.addVariable(v2);
		model.addVariable(v2);
		
		//model.addConstraint(Choco.eq(v1, Choco.plus(v2,v3)));
		model.addConstraint(Choco.eq(v1, Choco.mult(v2,v3)));
		solver.read(model);
		
		System.out.println("start solving");	
		solver.solve();
		solver.checkSolution();
		System.out.println(solver.pretty());
	}

output:
Pb[3 vars, 0 tasks, 1 cons]
Limits  Solutions: 1
  Time (ms): 30871
  Nodes: 4
  Backtracks: 0
  Restarts: 0
==== VARIABLES ====
v1:0[1]{0}
v2:0[1]{0}
v3:0[1]{0}
==== TASKS ====
==== CONSTRAINTS ====
GAC3rmValidLarge({v1:0[1]{0}, v2:0[1]{0}, v3:0[1]{0}}) relation: