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 /**
021 * Base interface for discrete distributions.
022 *
023 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
024 */
025 public interface DiscreteDistribution extends Distribution {
026 /**
027 * For a random variable X whose values are distributed according
028 * to this distribution, this method returns P(X = x). In other words, this
029 * method represents the probability mass function, or PMF for the distribution.
030 *
031 * @param x the value at which the probability mass function is evaluated.
032 * @return the value of the probability mass function at x
033 */
034 double probability(double x);
035 }