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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  /**
20   * Sampling from a Gaussian distribution with given mean and
21   * standard deviation.
22   *
23   * @since 1.1
24   */
25  public class GaussianSampler implements ContinuousSampler {
26      /** Mean. */
27      private final double mean;
28      /** standardDeviation. */
29      private final double standardDeviation;
30      /** Normalized Gaussian sampler. */
31      private final NormalizedGaussianSampler normalized;
32  
33      /**
34       * @param normalized Generator of N(0,1) Gaussian distributed random numbers.
35       * @param mean Mean of the Gaussian distribution.
36       * @param standardDeviation Standard deviation of the Gaussian distribution.
37       */
38      public GaussianSampler(NormalizedGaussianSampler normalized,
39                             double mean,
40                             double standardDeviation) {
41          this.normalized = normalized;
42          this.mean = mean;
43          this.standardDeviation = standardDeviation;
44      }
45  
46      /** {@inheritDoc} */
47      @Override
48      public double sample() {
49          return standardDeviation * normalized.sample() + mean;
50      }
51  
52      /** {@inheritDoc} */
53      @Override
54      public String toString() {
55          return "Gaussian deviate [" + normalized.toString() + "]";
56      }
57  }