| /* |
| * 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; |
| |
| import org.apache.commons.math.MathException; |
| |
| /** |
| * Interface for discrete distributions of integer-valued random variables. |
| * |
| * @version $Revision: 949535 $ $Date: 2010-05-30 19:00:15 +0200 (dim. 30 mai 2010) $ |
| */ |
| public interface IntegerDistribution extends DiscreteDistribution { |
| /** |
| * For a random variable X whose values are distributed according |
| * to this distribution, this method returns P(X = x). In other words, this |
| * method represents the probability mass function for the distribution. |
| * |
| * @param x the value at which the probability density function is evaluated. |
| * @return the value of the probability density function at x |
| */ |
| double probability(int x); |
| |
| /** |
| * For a random variable X whose values are distributed according |
| * to this distribution, this method returns P(X ≤ x). In other words, |
| * this method represents the probability distribution function, or PDF |
| * for the distribution. |
| * |
| * @param x the value at which the PDF is evaluated. |
| * @return PDF for this distribution. |
| * @throws MathException if the cumulative probability can not be |
| * computed due to convergence or other numerical errors. |
| */ |
| double cumulativeProbability(int x) throws MathException; |
| |
| /** |
| * For this distribution, X, this method returns P(x0 ≤ X ≤ x1). |
| * @param x0 the inclusive, lower bound |
| * @param x1 the inclusive, upper bound |
| * @return the cumulative probability. |
| * @throws MathException if the cumulative probability can not be |
| * computed due to convergence or other numerical errors. |
| * @throws IllegalArgumentException if x0 > x1 |
| */ |
| double cumulativeProbability(int x0, int x1) throws MathException; |
| |
| /** |
| * For this distribution, X, this method returns the largest x such that |
| * P(X ≤ x) <= p. |
| * <p> |
| * Note that this definition implies: <ul> |
| * <li> If there is a minimum value, <code>m</code>, with positive |
| * probability under (the density of) X, then <code>m - 1</code> is |
| * returned by <code>inverseCumulativeProbability(0).</code> If there is |
| * no such value <code>m, Integer.MIN_VALUE</code> is |
| * returned.</li> |
| * <li> If there is a maximum value, <code>M</code>, such that |
| * P(X ≤ M) =1, then <code>M</code> is returned by |
| * <code>inverseCumulativeProbability(1).</code> |
| * If there is no such value, <code>M, Integer.MAX_VALUE</code> is |
| * returned.</li></ul></p> |
| * |
| * @param p the cumulative probability. |
| * @return the largest x such that P(X ≤ x) <= p |
| * @throws MathException if the inverse cumulative probability can not be |
| * computed due to convergence or other numerical errors. |
| * @throws IllegalArgumentException if p is not between 0 and 1 (inclusive) |
| */ |
| int inverseCumulativeProbability(double p) throws MathException; |
| } |