/**
* Java Modular Image Synthesis Toolkit (JMIST)
* Copyright (C) 2008-2013 Bradley W. Kimmel
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package ca.eandb.jmist.framework.job.mlt;
import java.util.ArrayList;
import java.util.List;
import ca.eandb.jmist.framework.Random;
import ca.eandb.jmist.framework.path.Path;
import ca.eandb.jmist.framework.random.CategoricalRandom;
import ca.eandb.util.DoubleArray;
/**
* @author brad
*
*/
public final class CompositePathMutator implements PathMutator {
private final List<PathMutator> mutators = new ArrayList<PathMutator>();
private final DoubleArray weights = new DoubleArray();
private CategoricalRandom random = null;
public CompositePathMutator add(double weight, PathMutator mutator) {
mutators.add(mutator);
weights.add(weight);
random = null;
return this;
}
private void ensureReady() {
if (random == null) {
synchronized (this) {
if (random == null) {
random = new CategoricalRandom(weights);
}
}
}
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.job.mlt.PathMutator#getTransitionPDF(ca.eandb.jmist.framework.path.Path, ca.eandb.jmist.framework.path.Path)
*/
public double getTransitionPDF(Path from, Path to) {
ensureReady();
double pdf = 0.0;
for (int i = 0, n = mutators.size(); i < n; i++) {
PathMutator mutator = mutators.get(i);
double weight = random.getProbability(i);
pdf += weight * mutator.getTransitionPDF(from, to);
}
return pdf;
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.job.mlt.PathMutator#mutate(ca.eandb.jmist.framework.path.Path, ca.eandb.jmist.framework.Random)
*/
public Path mutate(Path path, Random rnd) {
ensureReady();
int index = random.next(rnd);
PathMutator mutator = mutators.get(index);
return mutator.mutate(path, rnd);
}
}