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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  
18  package org.apache.commons.rng.examples.jmh.sampling.distribution;
19  
20  import org.openjdk.jmh.annotations.Benchmark;
21  import org.openjdk.jmh.annotations.BenchmarkMode;
22  import org.openjdk.jmh.annotations.Mode;
23  import org.openjdk.jmh.annotations.Warmup;
24  import org.openjdk.jmh.annotations.Measurement;
25  import org.openjdk.jmh.annotations.State;
26  import org.openjdk.jmh.annotations.Fork;
27  import org.openjdk.jmh.annotations.Scope;
28  import org.openjdk.jmh.annotations.OutputTimeUnit;
29  import java.util.concurrent.TimeUnit;
30  import java.util.Random;
31  
32  /**
33   * Benchmark for {@link Random#nextGaussian()} in order to compare
34   * the speed of generation of normally-distributed random numbers.
35   */
36  @BenchmarkMode(Mode.AverageTime)
37  @OutputTimeUnit(TimeUnit.NANOSECONDS)
38  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
39  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
40  @State(Scope.Benchmark)
41  @Fork(value = 1, jvmArgs = {"-server", "-Xms128M", "-Xmx128M"})
42  public class NextGaussianPerformance {
43      /** JDK's generator. */
44      private final Random random = new Random();
45  
46      /**
47       * The value.
48       *
49       * <p>This must NOT be final!</p>
50       */
51      private double value;
52  
53      /**
54       * Baseline for the JMH timing overhead for production of an {@code double} value.
55       *
56       * @return the {@code double} value
57       */
58      @Benchmark
59      public double baseline() {
60          return value;
61      }
62  
63      /**
64       * Run JDK random gaussian sampler.
65       *
66       * @return the double
67       */
68      @Benchmark
69      public double runJDKRandomGaussianSampler() {
70          return random.nextGaussian();
71      }
72  }