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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.math.distribution;
18  
19  /**
20   * The Gamma Distribution.
21   *
22   * <p>
23   * References:
24   * <ul>
25   * <li><a href="http://mathworld.wolfram.com/GammaDistribution.html">
26   * Gamma Distribution</a></li>
27   * </ul>
28   * </p>
29   *
30   * @version $Revision: 693598 $ $Date: 2008-09-09 16:37:08 -0400 (Tue, 09 Sep 2008) $
31   */
32  public interface GammaDistribution extends ContinuousDistribution, HasDensity<Double> {
33      /**
34       * Modify the shape parameter, alpha.
35       * @param alpha the new shape parameter.
36       */
37      void setAlpha(double alpha);
38      
39      /**
40       * Access the shape parameter, alpha
41       * @return alpha.
42       */
43      double getAlpha();
44      
45      /**
46       * Modify the scale parameter, beta.
47       * @param beta the new scale parameter.
48       */
49      void setBeta(double beta);
50      
51      /**
52       * Access the scale parameter, beta
53       * @return beta.
54       */
55      double getBeta();
56  
57      /**
58       * Return the probability density for a particular point.
59       * @param x  The point at which the density should be computed.
60       * @return  The pdf at point x.
61       */
62      double density(Double x);
63  }