| /* |
| * 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.rng.UniformRandomProvider; |
| import org.apache.commons.rng.core.source64.SplitMix64; |
| import org.apache.commons.rng.sampling.RandomAssert; |
| import org.apache.commons.rng.simple.RandomSource; |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| /** |
| * Test for the {@link ContinuousUniformSampler}. |
| */ |
| public class ContinuousUniformSamplerTest { |
| /** |
| * Test that the sampler algorithm does not require high to be above low. |
| */ |
| @Test |
| public void testNoRestrictionOnOrderOfLowAndHighParameters() { |
| final double low = 3.18; |
| final double high = 5.23; |
| final UniformRandomProvider rng = RandomSource.SPLIT_MIX_64.create(); |
| testSampleInRange(rng, low, high); |
| testSampleInRange(rng, high, low); |
| } |
| |
| private static void testSampleInRange(UniformRandomProvider rng, |
| double low, double high) { |
| final SharedStateContinuousSampler sampler = ContinuousUniformSampler.of(rng, low, high); |
| final double min = Math.min(low, high); |
| final double max = Math.max(low, high); |
| for (int i = 0; i < 10; i++) { |
| final double value = sampler.sample(); |
| Assert.assertTrue("Value not in range", value >= min && value <= max); |
| } |
| } |
| |
| /** |
| * Test the sampler excludes the bounds when the underlying generator returns long values |
| * that produce the limit of the uniform double output. |
| */ |
| @Test |
| public void testExcludeBounds() { |
| // A broken RNG that will return in an alternating sequence from 0 up or -1 down. |
| // This is either zero bits or all the bits |
| final UniformRandomProvider rng = new SplitMix64(0L) { |
| private long l1; |
| private long l2; |
| @Override |
| public long nextLong() { |
| long x; |
| if (l1 > l2) { |
| l2++; |
| // Descending sequence: -1, -2, -3, ... |
| x = -l2; |
| } else { |
| // Ascending sequence: 0, 1, 2, ... |
| x = l1++; |
| } |
| // Shift by 11 bits to reverse the shift performed when computing the next |
| // double from a long. |
| return x << 11; |
| } |
| }; |
| final double low = 3.18; |
| final double high = 5.23; |
| final SharedStateContinuousSampler sampler = |
| ContinuousUniformSampler.of(rng, low, high, true); |
| // Test the sampler excludes the end points |
| for (int i = 0; i < 10; i++) { |
| final double value = sampler.sample(); |
| Assert.assertTrue("Value not in range: " + value, value > low && value < high); |
| } |
| } |
| |
| /** |
| * Test the SharedStateSampler implementation. |
| */ |
| @Test |
| public void testSharedStateSampler() { |
| testSharedStateSampler(false); |
| testSharedStateSampler(true); |
| } |
| |
| /** |
| * Test the SharedStateSampler implementation. |
| * |
| * @param excludedBounds Set to true to exclude the bounds. |
| */ |
| private static void testSharedStateSampler(boolean excludedBounds) { |
| final UniformRandomProvider rng1 = RandomSource.SPLIT_MIX_64.create(0L); |
| final UniformRandomProvider rng2 = RandomSource.SPLIT_MIX_64.create(0L); |
| final double low = 1.23; |
| final double high = 4.56; |
| final SharedStateContinuousSampler sampler1 = |
| ContinuousUniformSampler.of(rng1, low, high, excludedBounds); |
| final SharedStateContinuousSampler sampler2 = sampler1.withUniformRandomProvider(rng2); |
| RandomAssert.assertProduceSameSequence(sampler1, sampler2); |
| } |
| |
| /** |
| * Test the sampler implementation with bounds excluded matches that with bounds included |
| * when the generator does not produce the limit of the uniform double output. |
| */ |
| @Test |
| public void testSamplerWithBoundsExcluded() { |
| // SplitMix64 only returns zero once in the output. Seeded with zero it outputs zero |
| // at the end of the period. |
| final UniformRandomProvider rng1 = RandomSource.SPLIT_MIX_64.create(0L); |
| final UniformRandomProvider rng2 = RandomSource.SPLIT_MIX_64.create(0L); |
| final double low = 1.23; |
| final double high = 4.56; |
| final SharedStateContinuousSampler sampler1 = |
| ContinuousUniformSampler.of(rng1, low, high, false); |
| final SharedStateContinuousSampler sampler2 = |
| ContinuousUniformSampler.of(rng2, low, high, true); |
| RandomAssert.assertProduceSameSequence(sampler1, sampler2); |
| } |
| } |