This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-rng.git
commit eb34b308ee8cdc7baabd4566747a366765f0b2a4
Author: Alex Herbert <aherb...@apache.org>
AuthorDate: Sat Jun 29 11:43:09 2019 +0100
RNG-102: RandomAssert utility for testing samplers.
---
.../commons/rng/sampling/SharedStateSampler.java | 38 +++++++
.../apache/commons/rng/sampling/RandomAssert.java | 116 +++++++++++++++++++++
2 files changed, 154 insertions(+)
diff --git
a/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/SharedStateSampler.java
b/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/SharedStateSampler.java
new file mode 100644
index 0000000..ea928d6
--- /dev/null
+++
b/commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/SharedStateSampler.java
@@ -0,0 +1,38 @@
+/*
+ * 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;
+
+import org.apache.commons.rng.UniformRandomProvider;
+
+/**
+ * Applies to samplers that can share state between instances. Samplers can be
created with a
+ * new source of randomness that sample from the same state.
+ *
+ * @param <R> Type of the sampler.
+ * @since 1.3
+ */
+public interface SharedStateSampler<R> {
+ /**
+ * Create a new instance of the sampler with the same underlying state
using the given
+ * uniform random provider as the source of randomness.
+ *
+ * @param rng Generator of uniformly distributed random numbers.
+ * @return the sampler
+ */
+ R withUniformRandomProvider(UniformRandomProvider rng);
+}
diff --git
a/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/RandomAssert.java
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/RandomAssert.java
new file mode 100644
index 0000000..113471e
--- /dev/null
+++
b/commons-rng-sampling/src/test/java/org/apache/commons/rng/sampling/RandomAssert.java
@@ -0,0 +1,116 @@
+/*
+ * 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;
+
+import org.junit.Assert;
+
+import org.apache.commons.rng.sampling.distribution.ContinuousSampler;
+import org.apache.commons.rng.sampling.distribution.DiscreteSampler;
+
+/**
+ * Utility class for testing random samplers.
+ */
+public final class RandomAssert {
+ /** Number of samples to generate to test for equal sequences. */
+ private static final int SAMPLES = 10;
+
+ /**
+ * Defines a generic sampler.
+ *
+ * @param <T> the type of the sample
+ */
+ public interface Sampler<T> {
+ /**
+ * Creates a sample.
+ *
+ * @return a sample.
+ */
+ T sample();
+ }
+
+ /**
+ * Class contains only static methods.
+ */
+ private RandomAssert() {}
+
+ /**
+ * Exercise the {@link ContinuousSampler} interface, and
+ * ensure that the two samplers produce the same sequence.
+ *
+ * @param sampler1 First sampler.
+ * @param sampler2 Second sampler.
+ */
+ public static void assertProduceSameSequence(ContinuousSampler sampler1,
+ ContinuousSampler sampler2) {
+ for (int i = 0; i < SAMPLES; i++) {
+ Assert.assertEquals(sampler1.sample(), sampler2.sample(), 0.0);
+ }
+ }
+
+ /**
+ * Exercise the {@link DiscreteSampler} interface, and
+ * ensure that the two samplers produce the same sequence.
+ *
+ * @param sampler1 First sampler.
+ * @param sampler2 Second sampler.
+ */
+ public static void assertProduceSameSequence(DiscreteSampler sampler1,
+ DiscreteSampler sampler2) {
+ for (int i = 0; i < SAMPLES; i++) {
+ Assert.assertEquals(sampler1.sample(), sampler2.sample());
+ }
+ }
+
+ /**
+ * Exercise the {@link Sampler} interface, and
+ * ensure that the two samplers produce the same sequence.
+ *
+ * <p>Arrays are tested using {@link Assert#assertArrayEquals(Object[],
Object[])}
+ * which handles primitive arrays using exact equality and objects using
+ * {@link Object#equals(Object)}. Otherwise {@link
Assert#assertEquals(Object, Object)}
+ * is used which makes use of {@link Object#equals(Object)}.</p>
+ *
+ * <p>This should be used to test samplers of any type by wrapping the
sample method
+ * to an anonymous {@link Sampler} class.</p>
+ *
+ * @param sampler1 First sampler.
+ * @param sampler2 Second sampler.
+ */
+ public static <T> void assertProduceSameSequence(Sampler<T> sampler1,
+ Sampler<T> sampler2) {
+ for (int i = 0; i < SAMPLES; i++) {
+ final T value1 = sampler1.sample();
+ final T value2 = sampler2.sample();
+ if (isArray(value1) && isArray(value2)) {
+ Assert.assertArrayEquals((Object[]) value1, (Object[]) value2);
+ } else {
+ Assert.assertEquals(value1, value2);
+ }
+ }
+ }
+
+ /**
+ * Checks if the object is an array.
+ *
+ * @param object Object.
+ * @return true if an array
+ */
+ private static boolean isArray(Object object) {
+ return object != null && object.getClass().isArray();
+ }
+}
