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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.Test;
23  
24  /**
25   * Test for the {@link InverseTransformDiscreteSampler}.
26   */
27  public class InverseTransformDiscreteSamplerTest {
28      /**
29       * Test the SharedStateSampler implementation.
30       */
31      @Test
32      public void testSharedStateSampler() {
33          DiscreteInverseCumulativeProbabilityFunction function =
34              new DiscreteInverseCumulativeProbabilityFunction() {
35                  @Override
36                  public int inverseCumulativeProbability(double p) {
37                      return (int) Math.round(789 * p);
38                  }
39          };
40          final UniformRandomProvider rng1 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
41          final UniformRandomProvider rng2 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
42          final SharedStateDiscreteSampler sampler1 =
43              InverseTransformDiscreteSampler.of(rng1, function);
44          final SharedStateDiscreteSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
45          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
46      }
47  }