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Posted to dev@commons.apache.org by ps...@apache.org on 2004/05/30 00:51:32 UTC
cvs commit: jakarta-commons/math/src/test/org/apache/commons/math/distribution ContinuousDistributionAbstractTest.java
psteitz 2004/05/29 15:51:32
Added: math/src/test/org/apache/commons/math/distribution
ContinuousDistributionAbstractTest.java
Log:
Initial commit.
Revision Changes Path
1.1 jakarta-commons/math/src/test/org/apache/commons/math/distribution/ContinuousDistributionAbstractTest.java
Index: ContinuousDistributionAbstractTest.java
===================================================================
/*
* Copyright 2004 The Apache Software Foundation.
*
* Licensed 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.math.distribution;
import junit.framework.TestCase;
import org.apache.commons.math.TestUtils;
/**
* Abstract base class for {@link ContinuousDistribution} tests.
* <p>
* To create a concrete test class for a continuous distribution implementation,
* implement makeDistribution() to return a distribution instance to use in
* tests and each of the test data generation methods below. In each case, the
* test points and test values arrays returned represent parallel arrays of
* inputs and expected values for the distribution returned by makeDistribution().
* <p>
* makeCumulativeTestPoints() -- arguments used to test cumulative probabilities
* makeCumulativeTestValues() -- expected cumulative probabilites
* makeInverseCumulativeTestPoints() -- arguments used to test inverse cdf evaluation
* makeInverseCumulativeTestValues() -- expected inverse cdf values
* <p>
* To implement additional test cases with different distribution instances and test data,
* use the setXxx methods for the instance data in test cases and call the verifyXxx methods
* to verify results.
* <p>
* Error tolerance can be overriden by implementing getTolerance().
*
* @version $Revision: 1.1 $ $Date: 2004/05/29 22:51:32 $
*/
public abstract class ContinuousDistributionAbstractTest extends TestCase {
//-------------------- Private test instance data -------------------------
/** Discrete distribution instance used to perform tests */
private ContinuousDistribution distribution;
/** Tolerance used in comparing expected and returned values */
private double tolerance = 1E-4;
/** Arguments used to test cumulative probability density calculations */
private double[] cumulativeTestPoints;
/** Values used to test cumulative probability density calculations */
private double[] cumulativeTestValues;
/** Arguments used to test inverse cumulative probability density calculations */
private double[] inverseCumulativeTestPoints;
/** Values used to test inverse cumulative probability density calculations */
private double[] inverseCumulativeTestValues;
//-------------------------------------------------------------------------
/**
* Constructor for DiscreteDistributionAbstractTest.
* @param name
*/
public ContinuousDistributionAbstractTest(String name) {
super(name);
}
//-------------------- Abstract methods -----------------------------------
/** Creates the default continuous distribution instance to use in tests. */
public abstract ContinuousDistribution makeDistribution();
/** Creates the default cumulative probability density test input values */
public abstract double[] makeCumulativeTestPoints();
/** Creates the default cumulative probability density test expected values */
public abstract double[] makeCumulativeTestValues();
//---- Default implementations of inverse test data generation methods ----
/** Creates the default inverse cumulative probability test input values */
public double[] makeInverseCumulativeTestPoints() {
return makeCumulativeTestValues();
}
/** Creates the default inverse cumulative probability density test expected values */
public double[] makeInverseCumulativeTestValues() {
return makeCumulativeTestPoints();
}
//-------------------- Setup / tear down ----------------------------------
/**
* Setup sets all test instance data to default values
*/
protected void setUp() throws Exception {
super.setUp();
distribution = makeDistribution();
cumulativeTestPoints = makeCumulativeTestPoints();
cumulativeTestValues = makeCumulativeTestValues();
inverseCumulativeTestPoints = makeInverseCumulativeTestPoints();
inverseCumulativeTestValues = makeInverseCumulativeTestValues();
}
/**
* Cleans up test instance data
*/
protected void tearDown() throws Exception {
super.tearDown();
distribution = null;
cumulativeTestPoints = null;
cumulativeTestValues = null;
inverseCumulativeTestPoints = null;
inverseCumulativeTestValues = null;
}
//-------------------- Verification methods -------------------------------
/**
* Verifies that cumulative probability density calculations match expected values
* using current test instance data
*/
protected void verifyCumulativeProbabilities() throws Exception {
for (int i = 0; i < cumulativeTestPoints.length; i++) {
TestUtils.assertEquals("Incorrect cumulative probability value returned for "
+ cumulativeTestPoints[i], cumulativeTestValues[i],
distribution.cumulativeProbability(cumulativeTestPoints[i]),
getTolerance());
}
}
/**
* Verifies that inverse cumulative probability density calculations match exptected values
* using current test instance data
*/
protected void verifyInverseCumulativeProbabilities() throws Exception {
for (int i = 0; i < inverseCumulativeTestPoints.length; i++) {
TestUtils.assertEquals("Incorrect inverse cumulative probability value returned for "
+ inverseCumulativeTestPoints[i], inverseCumulativeTestValues[i],
distribution.inverseCumulativeProbability(inverseCumulativeTestPoints[i]),
getTolerance());
}
}
//------------------------ Default test cases -----------------------------
/**
* Verifies that cumulative probability density calculations match exptected values
* using default test instance data
*/
public void testCumulativeProbabilities() throws Exception {
verifyCumulativeProbabilities();
}
/**
* Verifies that inverse cumulative probability density calculations match exptected values
* using default test instance data
*/
public void testInverseCumulativeProbabilities() throws Exception {
verifyInverseCumulativeProbabilities();
}
/**
* Verifies that probability computations are consistent
*/
public void testConsistency() throws Exception {
for (int i=1; i < cumulativeTestPoints.length; i++) {
// check that cdf(x, x) = 0
TestUtils.assertEquals(0d,
distribution.cumulativeProbability
(cumulativeTestPoints[i], cumulativeTestPoints[i]), tolerance);
// check that P(a < X < b) = P(X < b) - P(X < a)
double upper = Math.max(cumulativeTestPoints[i], cumulativeTestPoints[i -1]);
double lower = Math.min(cumulativeTestPoints[i], cumulativeTestPoints[i -1]);
double diff = distribution.cumulativeProbability(upper) -
distribution.cumulativeProbability(lower);
double direct = distribution.cumulativeProbability(lower, upper);
TestUtils.assertEquals("Inconsistent cumulative probabilities for ("
+ lower + "," + upper + ")", diff, direct, tolerance);
}
}
/**
* Verifies that illegal arguments are correctly handled
*/
public void testIllegalArguments() throws Exception {
try {
distribution.cumulativeProbability(1, 0);
fail("Expecting IllegalArgumentException for bad cumulativeProbability interval");
} catch (IllegalArgumentException ex) {
// expected
}
try {
distribution.inverseCumulativeProbability(-1);
fail("Expecting IllegalArgumentException for p = -1");
} catch (IllegalArgumentException ex) {
// expected
}
try {
distribution.inverseCumulativeProbability(2);
fail("Expecting IllegalArgumentException for p = 2");
} catch (IllegalArgumentException ex) {
// expected
}
}
//------------------ Getters / Setters for test instance data -----------
/**
* @return Returns the cumulativeTestPoints.
*/
protected double[] getCumulativeTestPoints() {
return cumulativeTestPoints;
}
/**
* @param cumulativeTestPoints The cumulativeTestPoints to set.
*/
protected void setCumulativeTestPoints(double[] cumulativeTestPoints) {
this.cumulativeTestPoints = cumulativeTestPoints;
}
/**
* @return Returns the cumulativeTestValues.
*/
protected double[] getCumulativeTestValues() {
return cumulativeTestValues;
}
/**
* @param cumulativeTestValues The cumulativeTestValues to set.
*/
protected void setCumulativeTestValues(double[] cumulativeTestValues) {
this.cumulativeTestValues = cumulativeTestValues;
}
/**
* @return Returns the distribution.
*/
protected ContinuousDistribution getDistribution() {
return distribution;
}
/**
* @param distribution The distribution to set.
*/
protected void setDistribution(ContinuousDistribution distribution) {
this.distribution = distribution;
}
/**
* @return Returns the inverseCumulativeTestPoints.
*/
protected double[] getInverseCumulativeTestPoints() {
return inverseCumulativeTestPoints;
}
/**
* @param inverseCumulativeTestPoints The inverseCumulativeTestPoints to set.
*/
protected void setInverseCumulativeTestPoints(double[] inverseCumulativeTestPoints) {
this.inverseCumulativeTestPoints = inverseCumulativeTestPoints;
}
/**
* @return Returns the inverseCumulativeTestValues.
*/
protected double[] getInverseCumulativeTestValues() {
return inverseCumulativeTestValues;
}
/**
* @param inverseCumulativeTestValues The inverseCumulativeTestValues to set.
*/
protected void setInverseCumulativeTestValues(double[] inverseCumulativeTestValues) {
this.inverseCumulativeTestValues = inverseCumulativeTestValues;
}
/**
* @return Returns the tolerance.
*/
protected double getTolerance() {
return tolerance;
}
/**
* @param tolerance The tolerance to set.
*/
protected void setTolerance(double tolerance) {
this.tolerance = tolerance;
}
}
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