/*
* 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.commons.math3.random;
import java.net.URL;
import java.util.Arrays;
import org.apache.commons.math3.RetryRunner;
import org.apache.commons.math3.exception.MathIllegalStateException;
import org.apache.commons.math3.exception.ZeroException;
import org.apache.commons.math3.stat.descriptive.SummaryStatistics;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
/**
* Test cases for the ValueServer class.
*
*/
@RunWith(RetryRunner.class)
public final class ValueServerTest {
private ValueServer vs = new ValueServer(new Well19937c(100));
@Before
public void setUp() {
vs.setMode(ValueServer.DIGEST_MODE);
URL url = getClass().getResource("testData.txt");
vs.setValuesFileURL(url);
}
/**
* Generate 1000 random values and make sure they look OK.<br>
* Note that there is a non-zero (but very small) probability that
* these tests will fail even if the code is working as designed.
*/
@Test
public void testNextDigest() throws Exception {
double next = 0.0;
double tolerance = 0.1;
vs.computeDistribution();
Assert.assertTrue("empirical distribution property",
vs.getEmpiricalDistribution() != null);
SummaryStatistics stats = new SummaryStatistics();
for (int i = 1; i < 1000; i++) {
next = vs.getNext();
stats.addValue(next);
}
Assert.assertEquals("mean", 5.069831575018909, stats.getMean(), tolerance);
Assert.assertEquals("std dev", 1.0173699343977738, stats.getStandardDeviation(),
tolerance);
vs.computeDistribution(500);
stats = new SummaryStatistics();
for (int i = 1; i < 1000; i++) {
next = vs.getNext();
stats.addValue(next);
}
Assert.assertEquals("mean", 5.069831575018909, stats.getMean(), tolerance);
Assert.assertEquals("std dev", 1.0173699343977738, stats.getStandardDeviation(),
tolerance);
}
/**
* Verify that when provided with fixed seeds, stochastic modes
* generate fixed sequences. Verifies the fix for MATH-654.
*/
@Test
public void testFixedSeed() throws Exception {
ValueServer valueServer = new ValueServer();
URL url = getClass().getResource("testData.txt");
valueServer.setValuesFileURL(url);
valueServer.computeDistribution();
checkFixedSeed(valueServer, ValueServer.DIGEST_MODE);
checkFixedSeed(valueServer, ValueServer.EXPONENTIAL_MODE);
checkFixedSeed(valueServer, ValueServer.GAUSSIAN_MODE);
checkFixedSeed(valueServer, ValueServer.UNIFORM_MODE);
}
/**
* Do the check for {@link #testFixedSeed()}
* @param mode ValueServer mode
*/
private void checkFixedSeed(ValueServer valueServer, int mode) throws Exception {
valueServer.reSeed(1000);
valueServer.setMode(mode);
double[][] values = new double[2][100];
for (int i = 0; i < 100; i++) {
values[0][i] = valueServer.getNext();
}
valueServer.reSeed(1000);
for (int i = 0; i < 100; i++) {
values[1][i] = valueServer.getNext();
}
Assert.assertTrue(Arrays.equals(values[0], values[1]));
}
/**
* Make sure exception thrown if digest getNext is attempted
* before loading empiricalDistribution.
*/
@Test
public void testNextDigestFail() throws Exception {
try {
vs.getNext();
Assert.fail("Expecting IllegalStateException");
} catch (IllegalStateException ex) {}
}
@Test
public void testEmptyReplayFile() throws Exception {
try {
URL url = getClass().getResource("emptyFile.txt");
vs.setMode(ValueServer.REPLAY_MODE);
vs.setValuesFileURL(url);
vs.getNext();
Assert.fail("an exception should have been thrown");
} catch (MathIllegalStateException mise) {
// expected behavior
}
}
@Test
public void testEmptyDigestFile() throws Exception {
try {
URL url = getClass().getResource("emptyFile.txt");
vs.setMode(ValueServer.DIGEST_MODE);
vs.setValuesFileURL(url);
vs.computeDistribution();
Assert.fail("an exception should have been thrown");
} catch (ZeroException ze) {
// expected behavior
}
}
/**
* Test ValueServer REPLAY_MODE using values in testData file.<br>
* Check that the values 1,2,1001,1002 match data file values 1 and 2.
* the sample data file.
*/
@Test
public void testReplay() throws Exception {
double firstDataValue = 4.038625496201205;
double secondDataValue = 3.6485326248346936;
double tolerance = 10E-15;
double compareValue = 0.0d;
vs.setMode(ValueServer.REPLAY_MODE);
vs.resetReplayFile();
compareValue = vs.getNext();
Assert.assertEquals(compareValue,firstDataValue,tolerance);
compareValue = vs.getNext();
Assert.assertEquals(compareValue,secondDataValue,tolerance);
for (int i = 3; i < 1001; i++) {
compareValue = vs.getNext();
}
compareValue = vs.getNext();
Assert.assertEquals(compareValue,firstDataValue,tolerance);
compareValue = vs.getNext();
Assert.assertEquals(compareValue,secondDataValue,tolerance);
vs.closeReplayFile();
// make sure no NPE
vs.closeReplayFile();
}
/**
* Test other ValueServer modes
*/
@Test
public void testModes() throws Exception {
vs.setMode(ValueServer.CONSTANT_MODE);
vs.setMu(0);
Assert.assertEquals("constant mode test",vs.getMu(),vs.getNext(),Double.MIN_VALUE);
vs.setMode(ValueServer.UNIFORM_MODE);
vs.setMu(2);
double val = vs.getNext();
Assert.assertTrue(val > 0 && val < 4);
vs.setSigma(1);
vs.setMode(ValueServer.GAUSSIAN_MODE);
val = vs.getNext();
Assert.assertTrue("gaussian value close enough to mean",
val < vs.getMu() + 100*vs.getSigma());
vs.setMode(ValueServer.EXPONENTIAL_MODE);
val = vs.getNext();
Assert.assertTrue(val > 0);
try {
vs.setMode(1000);
vs.getNext();
Assert.fail("bad mode, expecting IllegalStateException");
} catch (IllegalStateException ex) {
// ignored
}
}
/**
* Test fill
*/
@Test
public void testFill() throws Exception {
vs.setMode(ValueServer.CONSTANT_MODE);
vs.setMu(2);
double[] val = new double[5];
vs.fill(val);
for (int i = 0; i < 5; i++) {
Assert.assertEquals("fill test in place",2,val[i],Double.MIN_VALUE);
}
double v2[] = vs.fill(3);
for (int i = 0; i < 3; i++) {
Assert.assertEquals("fill test in place",2,v2[i],Double.MIN_VALUE);
}
}
/**
* Test getters to make Clover happy
*/
@Test
public void testProperties() throws Exception {
vs.setMode(ValueServer.CONSTANT_MODE);
Assert.assertEquals("mode test",ValueServer.CONSTANT_MODE,vs.getMode());
vs.setValuesFileURL("http://www.apache.org");
URL url = vs.getValuesFileURL();
Assert.assertEquals("valuesFileURL test","http://www.apache.org",url.toString());
}
}