/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.ga.watchmaker;
import junit.framework.TestCase;
import org.uncommons.maths.random.MersenneTwisterRNG;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class STFitnessEvaluatorTest extends TestCase {
private static class STFitnessEvaluatorMock<T> extends STFitnessEvaluator<T> {
private int nbcalls;
private List<Double> evaluations;
public void shouldReturn(List<Double> evaluations) {
this.evaluations = evaluations;
}
public int getNbCalls() {
return nbcalls;
}
@Override
protected void evaluate(List<? extends T> population,
List<Double> evaluations) {
nbcalls++;
evaluations.addAll(this.evaluations);
}
@Override
public boolean isNatural() {
// Doesn't matter
return false;
}
}
/**
* Test method for
* {@link org.apache.mahout.ga.watchmaker.STFitnessEvaluator#evaluate(java.util.List, java.util.List)}.<br>
* <br>
* Make sure that evaluate() is not called twice for the same population.
*/
public void testEvaluateSamePopulation() {
STFitnessEvaluatorMock<Integer> mock = new STFitnessEvaluatorMock<Integer>();
Random rng = new MersenneTwisterRNG();
int size = 100;
List<Integer> population = randomInts(size, rng);
List<Double> evaluations = randomFloats(size, rng);
mock.shouldReturn(evaluations);
for (int index = 0; index < size; index++) {
Integer candidate = population.get(index);
assertEquals(evaluations.get(index), mock.getFitness(candidate, population));
}
// getFitness() should be called once
assertEquals(1, mock.getNbCalls());
}
/**
* Test method for
* {@link org.apache.mahout.ga.watchmaker.STFitnessEvaluator#evaluate(java.util.List, java.util.List)}.<br>
* <br>
* Make sure that evaluate() is called as many different populations are
* passed to getFitness().
*/
public void testEvaluateDifferentPopulations() {
STFitnessEvaluatorMock<Integer> mock = new STFitnessEvaluatorMock<Integer>();
Random rng = new MersenneTwisterRNG();
// generate a population A
int size = 100;
List<Integer> population = randomInts(size, rng);
List<Double> evaluations = randomFloats(size, rng);
mock.shouldReturn(evaluations);
// call with population A
mock.getFitness(population.get(rng.nextInt(size)), population);
// generate a new population B
population = randomInts(size, rng);
// call with population B
mock.getFitness(population.get(rng.nextInt(size)), population);
// getFitness() should be called twice
assertEquals(2, mock.getNbCalls());
}
private static List<Integer> randomInts(int size, Random rng) {
List<Integer> population = new ArrayList<Integer>();
for (int index = 0; index < size; index++)
population.add(rng.nextInt());
return population;
}
private static List<Double> randomFloats(int size, Random rng) {
List<Double> population = new ArrayList<Double>();
for (int index = 0; index < size; index++)
population.add(rng.nextDouble());
return population;
}
}