Re: [Choco-users] Variable ordering heuristics

[<gro...@em...>]

The default branching algorithm is a simple algorithm which assigns values to
variables (AssignVar). So you can easily do what you want thanks to the Solver
API :

* pb.getSolver().setVarSelector(IVarSelector varSelector) selects a variable
ordering heuristics.

So you have to define your own class implementing this interface. For instance,
you can use the following code :

// imports...

public class StaticOrderingHeuristic extends AbstractIntVarSelector {

  protected IntVar[] vars;

  public StaticOrderingHeuristic(IntVar[] vars) {
    this.vars = vars;
  }

  public IntVar selectIntVar() {
    for (int i = 0; i < vars.length; i++) {
      if (!vars[i].isInstantiated()) {
        return vars[i];
      }
    }
    return null;
  }
}

if you only give involved variables, it will totally ignore the other variables
during the branching algorithm

Hope it helps,

Guillaume

Selon Patrick Prosser <pa...@dc...>:

> Hi
> I am wanting to implement my own varaible ordering heuristic. In
> particular I would like to implement a static ordering heuristic that
> selects only some of the variables in the problem.
>
> cheers
>
> Patrick
>
>
> --
> Patrick Prosser       tel: +44 141 330 4934
> Computing Science     fax: +44 141 330 4913
> Glasgow University   mail: pa...@dc...
> G12 8RZ
> http://www.dcs.gla.ac.uk/~pat
>
>
>




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