[EvA] Trouble with constraints

[M.Kronfeld]

Hi there,

in EvA2, the prime mechanism for such a case would be to implement an
own problem range. Just override	
	double getRangeLowerBound(int dim)
and
	double getRangeUpperBound(int dim)
within your problem class to return the desired min/max values (e.g 0 or
1 in the first two dimensions and 0/max_value above). Doing that,
negative values will not even be regarded in the first place.

If you use the constraint mechanism, you are probably using soft
constraints by default, meaning that negative values are allowed, but
positive values are preferred with a certain weight (which can be
parameterized somehow I assume).

And by the way, I would not use random search for any plausible goal
except proving that random search wont work ;)

Best regards,
 Marcel


On 04/25/2012 06:02 PM, Johannes wrote:
> > I want to solve a rather simple problem with the EvA2 toolbox
> > using the Java interface.
> > Unfortunately I cannot get the constraints to work as they should,
> > I set them up, but they do not seem to be respected by the solver.
> >
> > If I did not misunderstand something fundamental on the issue, they
> > are supposed to work like shown below. Still, I get results containing
> > negative values, which should not be the case.
> > Any hints are appreciated.
> >
> > Best regards
> >
> > Johannes
> >
> > I run this:
> >
> > double[] lösung =
> > OptimizerFactory.optimizeToDouble(OptimizerFactory.RANDOM, new
> > EvA2Problem10(zielfunktion));
> >
> > with this class:
> >
> > public abstract class EvA2Problem extends AbstractProblemDouble {
> > 	
> > 	protected static final long serialVersionUID = 7005447722364059112L;
> > 	protected Abweichung abweichung;
> > 	
> > 	public EvA2Problem(Abweichung abweichung)
> > 	{
> > 		this.abweichung = abweichung;
> > 		setWithConstraints(true);
> > 		setDefaultRange(10.0);
> > 		setConstraints(new AbstractConstraint[]{
> > 				new IntervalConstraint(0, 0.0, 1.0),
> > 				new IntervalConstraint(1, 0.0, 1.0),
> > 				new IntervalConstraint(2, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(3, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(4, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(5, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(6, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(7, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(8, 0.0, Double.MAX_VALUE),
> > 				new IntervalConstraint(9, 0.0, Double.MAX_VALUE)
> > 		});
> > 	}
> >
> > 	@Override
> > 	public double[] eval(double[] values) {
> > 		return new double[]{abweichung.value(values)};
> > 	}
> > }
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> >