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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.math.distribution;
19  
20  /**
21   * Normal (Gauss) Distribution.
22   *
23   * <p>
24   * References:</p><p>
25   * <ul>
26   * <li><a href="http://mathworld.wolfram.com/NormalDistribution.html">
27   * Normal Distribution</a></li>
28   * </ul>
29   * </p>
30   *
31   * @version $Revision: 693598 $ $Date: 2008-09-09 16:37:08 -0400 (Tue, 09 Sep 2008) $
32   */
33  public interface NormalDistribution extends ContinuousDistribution, HasDensity<Double> {
34      /**
35       * Access the mean.
36       * @return mean for this distribution
37       */
38      double getMean();
39      /**
40       * Modify the mean.
41       * @param mean for this distribution
42       */
43      void setMean(double mean);
44      /**
45       * Access the standard deviation.
46       * @return standard deviation for this distribution
47       */
48      double getStandardDeviation();
49      /**
50       * Modify the standard deviation.
51       * @param sd standard deviation for this distribution
52       */
53      void setStandardDeviation(double sd);
54  
55      /**
56       * Return the probability density for a particular point.
57       * @param x  The point at which the density should be computed.
58       * @return  The pdf at point x.
59       */
60      double density(Double x);
61  }