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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.rng.sampling.distribution;
18  
19  import org.apache.commons.rng.UniformRandomProvider;
20  import org.apache.commons.rng.sampling.RandomAssert;
21  import org.apache.commons.rng.simple.RandomSource;
22  import org.junit.Assert;
23  import org.junit.Test;
24  
25  /**
26   * Test for the {@link ContinuousUniformSampler}.
27   */
28  public class ContinuousUniformSamplerTest {
29      /**
30       * Test that the sampler algorithm does not require high to be above low.
31       */
32      @Test
33      public void testNoRestrictionOnOrderOfLowAndHighParameters() {
34          final double low = 3.18;
35          final double high = 5.23;
36          final UniformRandomProvider rng = RandomSource.create(RandomSource.SPLIT_MIX_64);
37          testSampleInRange(rng, low, high);
38          testSampleInRange(rng, high, low);
39      }
40  
41      private static void testSampleInRange(UniformRandomProvider rng,
42                                            double low, double high) {
43          final SharedStateContinuousSampler sampler = ContinuousUniformSampler.of(rng, low, high);
44          final double min = Math.min(low,  high);
45          final double max = Math.max(low,  high);
46          for (int i = 0; i < 10; i++) {
47              final double value = sampler.sample();
48              Assert.assertTrue("Value not in range", value >= min && value <= max);
49          }
50      }
51  
52      /**
53       * Test the SharedStateSampler implementation.
54       */
55      @Test
56      public void testSharedStateSampler() {
57          final UniformRandomProvider rng1 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
58          final UniformRandomProvider rng2 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
59          final double low = 1.23;
60          final double high = 4.56;
61          final SharedStateContinuousSampler sampler1 =
62              ContinuousUniformSampler.of(rng1, low, high);
63          final SharedStateContinuousSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
64          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
65      }
66  }