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authorRaymond <siuchow@google.com>2015-04-02 10:43:13 -0700
committerRaymond <siuchow@google.com>2015-04-02 10:43:13 -0700
commitdee0849a9704d532af0b550146cbafbaa6ee1d19 (patch)
tree8ccce3a046c214fb609977b7fc53c40cef7f9ea5 /src/main/java/org/apache/commons/math/stat/descriptive/summary/SumOfLogs.java
parent55b0a5efc929efa9615babd3e760547f94e3518e (diff)
downloadapache-commons-math-dee0849a9704d532af0b550146cbafbaa6ee1d19.tar.gz
third party library: apache-commons-mathandroid-cts-6.0_r9android-cts-6.0_r8android-cts-6.0_r7android-cts-6.0_r6android-cts-6.0_r5android-cts-6.0_r4android-cts-6.0_r32android-cts-6.0_r31android-cts-6.0_r30android-cts-6.0_r3android-cts-6.0_r29android-cts-6.0_r28android-cts-6.0_r27android-cts-6.0_r26android-cts-6.0_r25android-cts-6.0_r24android-cts-6.0_r23android-cts-6.0_r22android-cts-6.0_r21android-cts-6.0_r20android-cts-6.0_r2android-cts-6.0_r19android-cts-6.0_r18android-cts-6.0_r17android-cts-6.0_r16android-cts-6.0_r15android-cts-6.0_r14android-cts-6.0_r13android-cts-6.0_r12android-cts-6.0_r1android-6.0.1_r9android-6.0.1_r81android-6.0.1_r80android-6.0.1_r8android-6.0.1_r79android-6.0.1_r78android-6.0.1_r77android-6.0.1_r74android-6.0.1_r73android-6.0.1_r72android-6.0.1_r70android-6.0.1_r7android-6.0.1_r69android-6.0.1_r68android-6.0.1_r67android-6.0.1_r66android-6.0.1_r65android-6.0.1_r63android-6.0.1_r62android-6.0.1_r61android-6.0.1_r60android-6.0.1_r59android-6.0.1_r58android-6.0.1_r57android-6.0.1_r56android-6.0.1_r55android-6.0.1_r54android-6.0.1_r53android-6.0.1_r52android-6.0.1_r51android-6.0.1_r50android-6.0.1_r5android-6.0.1_r49android-6.0.1_r48android-6.0.1_r47android-6.0.1_r46android-6.0.1_r45android-6.0.1_r43android-6.0.1_r42android-6.0.1_r41android-6.0.1_r40android-6.0.1_r4android-6.0.1_r33android-6.0.1_r32android-6.0.1_r31android-6.0.1_r30android-6.0.1_r3android-6.0.1_r28android-6.0.1_r27android-6.0.1_r26android-6.0.1_r25android-6.0.1_r24android-6.0.1_r22android-6.0.1_r21android-6.0.1_r20android-6.0.1_r18android-6.0.1_r17android-6.0.1_r16android-6.0.1_r13android-6.0.1_r12android-6.0.1_r11android-6.0.1_r10android-6.0.1_r1android-6.0.0_r7android-6.0.0_r6android-6.0.0_r5android-6.0.0_r41android-6.0.0_r4android-6.0.0_r3android-6.0.0_r26android-6.0.0_r25android-6.0.0_r24android-6.0.0_r23android-6.0.0_r2android-6.0.0_r13android-6.0.0_r12android-6.0.0_r11android-6.0.0_r1marshmallow-releasemarshmallow-mr3-releasemarshmallow-mr2-releasemarshmallow-mr1-releasemarshmallow-mr1-devmarshmallow-dr1.6-releasemarshmallow-dr1.5-releasemarshmallow-dr1.5-devmarshmallow-dr-releasemarshmallow-dr-dragon-releasemarshmallow-dr-devmarshmallow-devmarshmallow-cts-release
Change-Id: I52a325624a7f0dd652b362a9840626d6d9f3c42b
Diffstat (limited to 'src/main/java/org/apache/commons/math/stat/descriptive/summary/SumOfLogs.java')
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+/*
+ * 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.summary;
+
+import java.io.Serializable;
+
+import org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic;
+import org.apache.commons.math.util.FastMath;
+
+/**
+ * Returns the sum of the natural logs for this collection of values.
+ * <p>
+ * Uses {@link java.lang.Math#log(double)} to compute the logs. Therefore,
+ * <ul>
+ * <li>If any of values are < 0, the result is <code>NaN.</code></li>
+ * <li>If all values are non-negative and less than
+ * <code>Double.POSITIVE_INFINITY</code>, but at least one value is 0, the
+ * result is <code>Double.NEGATIVE_INFINITY.</code></li>
+ * <li>If both <code>Double.POSITIVE_INFINITY</code> and
+ * <code>Double.NEGATIVE_INFINITY</code> are among the values, the result is
+ * <code>NaN.</code></li>
+ * </ul></p>
+ * <p>
+ * <strong>Note that this implementation is not synchronized.</strong> If
+ * multiple threads access an instance of this class concurrently, and at least
+ * one of the threads invokes the <code>increment()</code> or
+ * <code>clear()</code> method, it must be synchronized externally.</p>
+ *
+ * @version $Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $
+ */
+public class SumOfLogs extends AbstractStorelessUnivariateStatistic implements Serializable {
+
+ /** Serializable version identifier */
+ private static final long serialVersionUID = -370076995648386763L;
+
+ /**Number of values that have been added */
+ private int n;
+
+ /**
+ * The currently running value
+ */
+ private double value;
+
+ /**
+ * Create a SumOfLogs instance
+ */
+ public SumOfLogs() {
+ value = 0d;
+ n = 0;
+ }
+
+ /**
+ * Copy constructor, creates a new {@code SumOfLogs} identical
+ * to the {@code original}
+ *
+ * @param original the {@code SumOfLogs} instance to copy
+ */
+ public SumOfLogs(SumOfLogs original) {
+ copy(original, this);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void increment(final double d) {
+ value += FastMath.log(d);
+ n++;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public double getResult() {
+ if (n > 0) {
+ return value;
+ } else {
+ return Double.NaN;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public long getN() {
+ return n;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void clear() {
+ value = 0d;
+ n = 0;
+ }
+
+ /**
+ * Returns the sum of the natural logs of the entries in the specified portion of
+ * the input array, or <code>Double.NaN</code> if the designated subarray
+ * is empty.
+ * <p>
+ * Throws <code>IllegalArgumentException</code> if the array is null.</p>
+ * <p>
+ * See {@link SumOfLogs}.</p>
+ *
+ * @param values the input array
+ * @param begin index of the first array element to include
+ * @param length the number of elements to include
+ * @return the sum of the natural logs of the values or Double.NaN if
+ * length = 0
+ * @throws IllegalArgumentException if the array is null or the array index
+ * parameters are not valid
+ */
+ @Override
+ public double evaluate(final double[] values, final int begin, final int length) {
+ double sumLog = Double.NaN;
+ if (test(values, begin, length)) {
+ sumLog = 0.0;
+ for (int i = begin; i < begin + length; i++) {
+ sumLog += FastMath.log(values[i]);
+ }
+ }
+ return sumLog;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public SumOfLogs copy() {
+ SumOfLogs result = new SumOfLogs();
+ copy(this, result);
+ return result;
+ }
+
+ /**
+ * Copies source to dest.
+ * <p>Neither source nor dest can be null.</p>
+ *
+ * @param source SumOfLogs to copy
+ * @param dest SumOfLogs to copy to
+ * @throws NullPointerException if either source or dest is null
+ */
+ public static void copy(SumOfLogs source, SumOfLogs dest) {
+ dest.setData(source.getDataRef());
+ dest.n = source.n;
+ dest.value = source.value;
+ }
+}