/**
* 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.ep;
import org.apache.mahout.common.MahoutTestCase;
import org.junit.Test;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
public final class EvolutionaryProcessTest extends MahoutTestCase {
@Test
public void testConverges() throws Exception {
State<Foo, Double> s0 = new State<Foo, Double>(new double[5], 1);
s0.setPayload(new Foo());
EvolutionaryProcess<Foo, Double> ep = new EvolutionaryProcess<Foo, Double>(10, 100, s0);
State<Foo, Double> best = null;
for (int i = 0; i < 20; i++) {
best = ep.parallelDo(new EvolutionaryProcess.Function<Payload<Double>>() {
@Override
public double apply(Payload<Double> payload, double[] params) {
int i = 1;
double sum = 0;
for (double x : params) {
sum += i * (x - i) * (x - i);
i++;
}
return -sum;
}
});
ep.mutatePopulation(3);
System.out.printf("%10.3f %.3f\n", best.getValue(), best.getOmni());
}
assertNotNull(best);
assertEquals(0.0, best.getValue(), 0.02);
}
private static class Foo implements Payload<Double> {
@Override
public Foo copy() {
return this;
}
@Override
public void update(double[] params) {
// ignore
}
@Override
public void write(DataOutput dataOutput) throws IOException {
// no-op
}
@Override
public void readFields(DataInput dataInput) throws IOException {
// no-op
}
}
}