/* * 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.stat.descriptive.moment; import java.io.Serializable; import org.apache.commons.math.MathRuntimeException; import org.apache.commons.math.exception.util.LocalizedFormats; import org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic; import org.apache.commons.math.stat.descriptive.StorelessUnivariateStatistic; import org.apache.commons.math.stat.descriptive.summary.SumOfLogs; import org.apache.commons.math.util.FastMath; /** * Returns the * geometric mean of the available values. *
* Uses a {@link SumOfLogs} instance to compute sum of logs and returns
* exp( 1/n (sum of logs) ).
Therefore,
NaN.
Double.POSITIVE_INFINITY
, but at least one value is 0, the
* result is 0.
Double.POSITIVE_INFINITY
and
* Double.NEGATIVE_INFINITY
are among the values, the result is
* NaN.
* Note that this implementation is not synchronized. If
* multiple threads access an instance of this class concurrently, and at least
* one of the threads invokes the increment()
or
* clear()
method, it must be synchronized externally.
* See {@link GeometricMean} for details on the computing algorithm.
*
* Throws IllegalArgumentException
if the array is null.
Sets the implementation for the sum of logs.
*This method must be activated before any data has been added - i.e., * before {@link #increment(double) increment} has been used to add data; * otherwise an IllegalStateException will be thrown.
* * @param sumLogImpl the StorelessUnivariateStatistic instance to use * for computing the log sum * @throws IllegalStateException if data has already been added * (i.e if n > 0) */ public void setSumLogImpl( StorelessUnivariateStatistic sumLogImpl) { checkEmpty(); this.sumOfLogs = sumLogImpl; } /** * Returns the currently configured sum of logs implementation * * @return the StorelessUnivariateStatistic implementing the log sum */ public StorelessUnivariateStatistic getSumLogImpl() { return sumOfLogs; } /** * Copies source to dest. *Neither source nor dest can be null.
* * @param source GeometricMean to copy * @param dest GeometricMean to copy to * @throws NullPointerException if either source or dest is null */ public static void copy(GeometricMean source, GeometricMean dest) { dest.setData(source.getDataRef()); dest.sumOfLogs = source.sumOfLogs.copy(); } /** * Throws IllegalStateException if n > 0. */ private void checkEmpty() { if (getN() > 0) { throw MathRuntimeException.createIllegalStateException( LocalizedFormats.VALUES_ADDED_BEFORE_CONFIGURING_STATISTIC, getN()); } } }