/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math.distribution;

/**
 * The Pascal distribution. The Pascal distribution is a special case of the
 * Negative Binomial distribution where the number of successes parameter is an
 * integer.
 * 
 * There are various ways to express the probability mass and distribution
 * functions for the Pascal distribution. The convention employed by the library
 * is to express these functions in terms of the number of failures in a
 * Bernoulli experiment [2].
 *
 * <p>
 * References:
 * <ol>
 * <li><a href="http://mathworld.wolfram.com/NegativeBinomialDistribution.html">
 * Negative Binomial Distribution</a></li> <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>
 * </ul>
 * </p>
 *
 * @version $Revision$ $Date$
 * @since 1.2
 */
public interface PascalDistribution extends IntegerDistribution {
	/**
	 * Access the number of successes for this distribution.
	 * 
	 * @return the number of successes
	 */
	int getNumberOfSuccesses();

	/**
	 * Access the probability of success for this distribution.
	 * 
	 * @return the probability of success
	 */
	double getProbabilityOfSuccess();

	/**
	 * Change the number of successes for this distribution.
	 * 
	 * @param successes
	 *            the new number of successes
	 */
	void setNumberOfSuccesses(int successes);

	/**
	 * Change the probability of success for this distribution.
	 * 
	 * @param p
	 *            the new probability of success
	 */
	void setProbabilityOfSuccess(double p);
}