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 * The Zipf (or zeta) Distribution.
22 * <p>
23 * References:
24 * <ul>
25 * <li><a href="http://mathworld.wolfram.com/ZipfDistribution.html">Zipf
26 * Distribution</a></li>
27 * </ul>
28 * </p>
29 *
30 * @version $Revision: 729291 $ $Date: 2008-12-24 05:47:53 -0500 (Wed, 24 Dec 2008) $
31 */
32 public interface ZipfDistribution extends IntegerDistribution {
33 /**
34 * Get the number of elements (e.g. corpus size) for the distribution.
35 *
36 * @return the number of elements
37 */
38 public int getNumberOfElements();
39
40 /**
41 * Set the number of elements (e.g. corpus size) for the distribution.
42 * The parameter value must be positive; otherwise an
43 * <code>IllegalArgumentException</code> is thrown.
44 *
45 * @param n the number of elements
46 * @throws IllegalArgumentException if n ≤ 0
47 */
48 public void setNumberOfElements(int n);
49
50 /**
51 * Get the exponent characterising the distribution.
52 *
53 * @return the exponent
54 */
55 public double getExponent();
56
57 /**
58 * Set the exponent characterising the distribution.
59 * The parameter value must be positive; otherwise an
60 * <code>IllegalArgumentException</code> is thrown.
61 *
62 * @param s the exponent
63 * @throws IllegalArgumentException if s ≤ 0.0
64 */
65 public void setExponent(double s);
66 }