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 package org.apache.commons.math.distribution; 18 19 /** 20 * The Chi-Squared Distribution. 21 * 22 * <p> 23 * References: 24 * <ul> 25 * <li><a href="http://mathworld.wolfram.com/Chi-SquaredDistribution.html"> 26 * Chi-Squared Distribution</a></li> 27 * </ul> 28 * </p> 29 * 30 * @version $Revision: 693598 $ $Date: 2008-09-09 16:37:08 -0400 (Tue, 09 Sep 2008) $ 31 */ 32 public interface ChiSquaredDistribution extends ContinuousDistribution, HasDensity<Double> { 33 /** 34 * Modify the degrees of freedom. 35 * @param degreesOfFreedom the new degrees of freedom. 36 */ 37 void setDegreesOfFreedom(double degreesOfFreedom); 38 39 /** 40 * Access the degrees of freedom. 41 * @return the degrees of freedom. 42 */ 43 double getDegreesOfFreedom(); 44 45 /** 46 * Return the probability density for a particular point. 47 * @param x The point at which the density should be computed. 48 * @return The pdf at point x. 49 */ 50 double density(Double x); 51 }