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aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git
The following commit(s) were added to refs/heads/master by this push:
new e27f4cf Added sampling InternalUtilsTest.
e27f4cf is described below
commit e27f4cfb0a80e639c1f319e6c237fc37af8d3b42
Author: Alex Herbert <aherb...@apache.org>
AuthorDate: Sun Mar 3 23:45:29 2019 +0000
Added sampling InternalUtilsTest.
---
.../rng/sampling/distribution/InternalUtils.java | 8 +-
.../sampling/distribution/InternalUtilsTest.java | 88 ++++++++++++++++++++++
2 files changed, 92 insertions(+), 4 deletions(-)
diff --git
a/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/InternalUtils.java
b/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/InternalUtils.java
index 287cc8f..d234440 100644
---
a/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/InternalUtils.java
+++
b/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/InternalUtils.java
@@ -39,8 +39,8 @@ class InternalUtils { // Class is package-private on purpose;
do not make it pub
/**
* @param n Argument.
* @return {@code n!}
- * @throws IllegalArgumentException if the result is too large to be
represented
- * by a {@code long} (i.e. if {@code n > 20}).
+ * @throws IndexOutOfBoundsException if the result is too large to be
represented
+ * by a {@code long} (i.e. if {@code n > 20}), or {@code n} is negative.
*/
public static long factorial(int n) {
return FACTORIALS[n];
@@ -64,7 +64,7 @@ class InternalUtils { // Class is package-private on purpose;
do not make it pub
*
* @param numValues Number of values of the function to compute.
* @param cache Existing cache.
- * @throw IllegalArgumentException if {@code numValues < 0}.
+ * @throw NegativeArraySizeException if {@code numValues < 0}.
*/
private FactorialLog(int numValues,
double[] cache) {
@@ -112,7 +112,7 @@ class InternalUtils { // Class is package-private on
purpose; do not make it pub
*
* @param n Argument.
* @return {@code log(n!)}.
- * @throws IllegalArgumentException if {@code n < 0}.
+ * @throw IndexOutOfBoundsException if {@code numValues < 0}.
*/
public double value(final int n) {
// Use cache of precomputed values.
diff --git
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
new file mode 100644
index 0000000..d1a3b6a
--- /dev/null
+++
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/distribution/InternalUtilsTest.java
@@ -0,0 +1,88 @@
+/*
+ * 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.rng.sampling.distribution;
+
+import org.apache.commons.math3.special.Gamma;
+import org.apache.commons.rng.sampling.distribution.InternalUtils.FactorialLog;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test for the {@link InternalUtils}.
+ */
+public class InternalUtilsTest {
+ /** The maximum value for n! that is representable as a long. */
+ private static final int MAX_REPRESENTABLE = 20;
+
+ @Test
+ public void testFactorial() {
+ Assert.assertEquals(1L, InternalUtils.factorial(0));
+ long result = 1;
+ for (int n = 1; n <= MAX_REPRESENTABLE; n++) {
+ result *= n;
+ Assert.assertEquals(result, InternalUtils.factorial(n));
+ }
+ }
+
+ @Test(expected = IndexOutOfBoundsException.class)
+ public void testFactorialThrowsWhenNegative() {
+ InternalUtils.factorial(-1);
+ }
+
+ @Test(expected = IndexOutOfBoundsException.class)
+ public void testFactorialThrowsWhenNotRepresentableAsLong() {
+ InternalUtils.factorial(MAX_REPRESENTABLE + 1);
+ }
+
+ @Test
+ public void testFactorialLog() {
+ // Cache size allows some of the factorials to be cached and some
+ // to be under the precomputed factorials.
+ FactorialLog factorialLog =
FactorialLog.create().withCache(MAX_REPRESENTABLE / 2);
+ Assert.assertEquals(0, factorialLog.value(0), 1e-10);
+ for (int n = 1; n <= MAX_REPRESENTABLE + 5; n++) {
+ // Use Commons math to compute logGamma(1 + n);
+ double expected = Gamma.logGamma(1 + n);
+ Assert.assertEquals(expected, factorialLog.value(n), 1e-10);
+ }
+ }
+
+ @Test
+ public void testFactorialLogCacheExpansion() {
+ // There is no way to determine if the cache values were reused but
this test
+ // exercises the method to ensure it does not error.
+ final FactorialLog factorialLog = FactorialLog.create()
+ // Edge case where cache
should not be copied (<2)
+ .withCache(1)
+ // Expand
+ .withCache(5)
+ // Expand more
+ .withCache(10)
+ // Contract
+ .withCache(5);
+ for (int n = 1; n <= 5; n++) {
+ // Use Commons math to compute logGamma(1 + n);
+ double expected = Gamma.logGamma(1 + n);
+ Assert.assertEquals(expected, factorialLog.value(n), 1e-10);
+ }
+ }
+
+ @Test(expected = IndexOutOfBoundsException.class)
+ public void testLogFactorialThrowsWhenNegative() {
+ FactorialLog.create().value(-1);
+ }
+}
