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 package org.apache.commons.math.distribution; 018 019 /** 020 * The Pascal distribution. The Pascal distribution is a special case of the 021 * Negative Binomial distribution where the number of successes parameter is an 022 * integer. 023 * 024 * There are various ways to express the probability mass and distribution 025 * functions for the Pascal distribution. The convention employed by the 026 * library is to express these functions in terms of the number of failures in 027 * a Bernoulli experiment [2]. 028 * 029 * <p> 030 * References: 031 * <ol> 032 * <li><a href="http://mathworld.wolfram.com/NegativeBinomialDistribution.html"> 033 * Negative Binomial Distribution</a></li> 034 * <oi><a href="http://en.wikipedia.org/wiki/Negative_binomial_distribution#Waiting_time_in_a_Bernoulli_process">Waiting Time in a Bernoulli Process</a></li> 035 * </ul> 036 * </p> 037 * 038 * @version $Revision: 670469 $ $Date: 2008-06-23 04:01:38 -0400 (Mon, 23 Jun 2008) $ 039 * @since 1.2 040 */ 041 public interface PascalDistribution extends IntegerDistribution { 042 /** 043 * Access the number of successes for this distribution. 044 * 045 * @return the number of successes 046 */ 047 int getNumberOfSuccesses(); 048 049 /** 050 * Access the probability of success for this distribution. 051 * 052 * @return the probability of success 053 */ 054 double getProbabilityOfSuccess(); 055 056 /** 057 * Change the number of successes for this distribution. 058 * 059 * @param successes the new number of successes 060 */ 061 void setNumberOfSuccesses(int successes); 062 063 /** 064 * Change the probability of success for this distribution. 065 * 066 * @param p the new probability of success 067 */ 068 void setProbabilityOfSuccess(double p); 069 }