001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.math.distribution;
019
020 /**
021 * The Zipf (or zeta) Distribution.
022 * <p>
023 * References:
024 * <ul>
025 * <li><a href="http://mathworld.wolfram.com/ZipfDistribution.html">Zipf
026 * Distribution</a></li>
027 * </ul>
028 * </p>
029 *
030 * @version $Revision: 729291 $ $Date: 2008-12-24 05:47:53 -0500 (Wed, 24 Dec 2008) $
031 */
032 public interface ZipfDistribution extends IntegerDistribution {
033 /**
034 * Get the number of elements (e.g. corpus size) for the distribution.
035 *
036 * @return the number of elements
037 */
038 public int getNumberOfElements();
039
040 /**
041 * Set the number of elements (e.g. corpus size) for the distribution.
042 * The parameter value must be positive; otherwise an
043 * <code>IllegalArgumentException</code> is thrown.
044 *
045 * @param n the number of elements
046 * @throws IllegalArgumentException if n ≤ 0
047 */
048 public void setNumberOfElements(int n);
049
050 /**
051 * Get the exponent characterising the distribution.
052 *
053 * @return the exponent
054 */
055 public double getExponent();
056
057 /**
058 * Set the exponent characterising the distribution.
059 * The parameter value must be positive; otherwise an
060 * <code>IllegalArgumentException</code> is thrown.
061 *
062 * @param s the exponent
063 * @throws IllegalArgumentException if s ≤ 0.0
064 */
065 public void setExponent(double s);
066 }