Author: psteitz
Date: Sun Jun 12 19:39:27 2011
New Revision: 1134966
URL: http://svn.apache.org/viewvc?rev=1134966&view=rev
Log:
Added standalone test class for AbstractIntegerDistribution default
implementations. JIRA: MATH-587.
Added:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java
(with props)
Added:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java?rev=1134966&view=auto
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java
(added)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java
Sun Jun 12 19:39:27 2011
@@ -0,0 +1,171 @@
+/*
+ * 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.math.distribution;
+
+import org.apache.commons.math.MathException;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test cases for AbstractIntegerDistribution default implementations
+ *
+ * @version $Id$
+ */
+public class AbtractIntegerDistributionTest {
+
+ protected final DiceDistribution diceDistribution = new DiceDistribution();
+ protected final double p = diceDistribution.probability(1);
+
+ @Test
+ public void testCumulativeProbabilitiesSingleIntegerArguments() throws
Exception {
+ int lower = 1;
+ for (int i = 1; i < 7; i++) {
+ Assert.assertEquals(p * i,
+ diceDistribution.cumulativeProbability(lower),
Double.MIN_VALUE);
+ lower++;
+ }
+ Assert.assertEquals(0,
+ diceDistribution.cumulativeProbability(-1), Double.MIN_VALUE);
+ Assert.assertEquals(1,
+ diceDistribution.cumulativeProbability(7), Double.MIN_VALUE);
+ }
+
+ @Test
+ public void testCumulativeProbabilitiesSingleDoubleArguments() throws
Exception {
+ int lower = 1;
+ double arg = 0;
+ for (int i = 1; i < 7; i++) {
+ // Exact integer
+ arg = lower;
+ Assert.assertEquals(p * i,
+ diceDistribution.cumulativeProbability(arg),
Double.MIN_VALUE);
+
+ // Add a fraction
+ arg = lower + Math.random();
+ Assert.assertEquals(p * i,
+ diceDistribution.cumulativeProbability(arg),
Double.MIN_VALUE);
+ lower++;
+ }
+ }
+
+ @Test
+ public void testCumulativeProbabilitiesRangeIntegerArguments() throws
Exception {
+ int lower = 1;
+ int upper = 6;
+ for (int i = 0; i < 2; i++) {
+ // cum(1,6) = p(1 <= X <= 6) = 1, cum(2,5) = 4/6, cum(3,4) = 2/6
+ Assert.assertEquals(1 - p * 2 * i,
+ diceDistribution.cumulativeProbability(lower, upper),
1E-12);
+ lower++;
+ upper--;
+ }
+ for (int i = 1; i < 7; i++) {
+ Assert.assertEquals(p, diceDistribution.cumulativeProbability(i,
i), 1E-12);
+ }
+ }
+
+ @Test
+ public void testCumulativeProbabilitiesRangeDoubleArguments() throws
Exception {
+ int lower = 1;
+ int upper = 6;
+ double dlower = lower;
+ double dupper = upper;
+ for (int i = 0; i < 2; i++) {
+ // cum(1,6) = p(1 <= X <= 6) = 1, cum(2,5) = 4/6, cum(3,4) = 2/6
+ // Exact integers
+ Assert.assertEquals(1 - p * 2 * i,
+ diceDistribution.cumulativeProbability(dlower, dupper),
1E-12);
+ // Subtract a fraction from lower, add to upper. Should be no
change.
+ dlower -= Math.random();
+ dupper += Math.random();
+ Assert.assertEquals(1 - p * 2 * i,
+ diceDistribution.cumulativeProbability(dlower, dupper),
1E-12);
+ lower++;
+ upper--;
+ dlower = lower;
+ dupper = upper;
+ }
+ for (int i = 1; i < 7; i++) {
+ lower = i;
+ Assert.assertEquals(p, diceDistribution.cumulativeProbability(
+ lower, lower), 1E-12);
+ Assert.assertEquals(p, diceDistribution.cumulativeProbability(
+ lower, lower + Math.random()), 1E-12);
+ Assert.assertEquals(p, diceDistribution.cumulativeProbability(
+ lower - Math.random(), lower), 1E-12);
+ Assert.assertEquals(p, diceDistribution.cumulativeProbability(
+ lower - Math.random(), lower + Math.random()), 1E-12);
+ }
+ }
+
+ /**
+ * Simple distribution modeling a 6-sided die
+ */
+ class DiceDistribution extends AbstractIntegerDistribution {
+ public static final long serialVersionUID = 23734213;
+ private final double p = 1d/6d;
+ public double probability(int x) {
+ if (x < 1 || x > 6) {
+ return 0;
+ } else {
+ return p;
+ }
+ }
+
+ @Override
+ public double cumulativeProbability(int x) throws MathException {
+ if (x < 1) {
+ return 0;
+ } else if (x >= 6) {
+ return 1;
+ } else {
+ return p * x;
+ }
+ }
+
+ @Override
+ protected int getDomainLowerBound(double p) {
+ return 1;
+ }
+
+ @Override
+ protected int getDomainUpperBound(double p) {
+ return 6;
+ }
+
+ @Override
+ public int getSupportLowerBound() {
+ return 1;
+ }
+
+ @Override
+ public int getSupportUpperBound() {
+ return 6;
+ }
+
+ @Override
+ protected double calculateNumericalMean() {
+ return 3.5;
+ }
+
+ @Override
+ protected double calculateNumericalVariance() {
+ return 12.5 - 3.5 * 3.5; // E(X^2) - E(X)^2
+ }
+ }
+}
Propchange:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/distribution/AbtractIntegerDistributionTest.java
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