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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.commons.math.distribution;
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import java.io.Serializable;
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import org.apache.commons.math.MathException;
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* Base class for probability distributions.
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* @version $Revision: 617953 $ $Date: 2008-02-02 22:54:00 -0700 (Sat, 02 Feb 2008) $
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public abstract class AbstractDistribution
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implements Distribution, Serializable {
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/** Serializable version identifier */
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private static final long serialVersionUID = -38038050983108802L;
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* Default constructor.
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protected AbstractDistribution() {
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* For a random variable X whose values are distributed according
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* to this distribution, this method returns P(x0 ≤ X ≤ x1).
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* The default implementation uses the identity</p>
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* P(x0 ≤ X ≤ x1) = P(X ≤ x1) - P(X ≤ x0) </p>
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* @param x0 the (inclusive) lower bound
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* @param x1 the (inclusive) upper bound
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* @return the probability that a random variable with this distribution
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* will take a value between <code>x0</code> and <code>x1</code>,
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* including the endpoints.
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* @throws MathException if the cumulative probability can not be
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* computed due to convergence or other numerical errors.
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* @throws IllegalArgumentException if <code>x0 > x1</code>
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public double cumulativeProbability(double x0, double x1)
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throws MathException {
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throw new IllegalArgumentException
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("lower endpoint must be less than or equal to upper endpoint");
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return cumulativeProbability(x1) - cumulativeProbability(x0);