Raymond | dee0849 | 2015-04-02 10:43:13 -0700 | [diff] [blame] | 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.stat.descriptive.rank; |
| 18 | |
| 19 | import java.io.Serializable; |
| 20 | |
| 21 | import org.apache.commons.math.stat.descriptive.AbstractStorelessUnivariateStatistic; |
| 22 | |
| 23 | /** |
| 24 | * Returns the maximum of the available values. |
| 25 | * <p> |
| 26 | * <ul> |
| 27 | * <li>The result is <code>NaN</code> iff all values are <code>NaN</code> |
| 28 | * (i.e. <code>NaN</code> values have no impact on the value of the statistic).</li> |
| 29 | * <li>If any of the values equals <code>Double.POSITIVE_INFINITY</code>, |
| 30 | * the result is <code>Double.POSITIVE_INFINITY.</code></li> |
| 31 | * </ul></p> |
| 32 | * <p> |
| 33 | * <strong>Note that this implementation is not synchronized.</strong> If |
| 34 | * multiple threads access an instance of this class concurrently, and at least |
| 35 | * one of the threads invokes the <code>increment()</code> or |
| 36 | * <code>clear()</code> method, it must be synchronized externally.</p> |
| 37 | * |
| 38 | * @version $Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $ |
| 39 | */ |
| 40 | public class Max extends AbstractStorelessUnivariateStatistic implements Serializable { |
| 41 | |
| 42 | /** Serializable version identifier */ |
| 43 | private static final long serialVersionUID = -5593383832225844641L; |
| 44 | |
| 45 | /** Number of values that have been added */ |
| 46 | private long n; |
| 47 | |
| 48 | /** Current value of the statistic */ |
| 49 | private double value; |
| 50 | |
| 51 | /** |
| 52 | * Create a Max instance |
| 53 | */ |
| 54 | public Max() { |
| 55 | n = 0; |
| 56 | value = Double.NaN; |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * Copy constructor, creates a new {@code Max} identical |
| 61 | * to the {@code original} |
| 62 | * |
| 63 | * @param original the {@code Max} instance to copy |
| 64 | */ |
| 65 | public Max(Max original) { |
| 66 | copy(original, this); |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * {@inheritDoc} |
| 71 | */ |
| 72 | @Override |
| 73 | public void increment(final double d) { |
| 74 | if (d > value || Double.isNaN(value)) { |
| 75 | value = d; |
| 76 | } |
| 77 | n++; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * {@inheritDoc} |
| 82 | */ |
| 83 | @Override |
| 84 | public void clear() { |
| 85 | value = Double.NaN; |
| 86 | n = 0; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * {@inheritDoc} |
| 91 | */ |
| 92 | @Override |
| 93 | public double getResult() { |
| 94 | return value; |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * {@inheritDoc} |
| 99 | */ |
| 100 | public long getN() { |
| 101 | return n; |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Returns the maximum of the entries in the specified portion of |
| 106 | * the input array, or <code>Double.NaN</code> if the designated subarray |
| 107 | * is empty. |
| 108 | * <p> |
| 109 | * Throws <code>IllegalArgumentException</code> if the array is null or |
| 110 | * the array index parameters are not valid.</p> |
| 111 | * <p> |
| 112 | * <ul> |
| 113 | * <li>The result is <code>NaN</code> iff all values are <code>NaN</code> |
| 114 | * (i.e. <code>NaN</code> values have no impact on the value of the statistic).</li> |
| 115 | * <li>If any of the values equals <code>Double.POSITIVE_INFINITY</code>, |
| 116 | * the result is <code>Double.POSITIVE_INFINITY.</code></li> |
| 117 | * </ul></p> |
| 118 | * |
| 119 | * @param values the input array |
| 120 | * @param begin index of the first array element to include |
| 121 | * @param length the number of elements to include |
| 122 | * @return the maximum of the values or Double.NaN if length = 0 |
| 123 | * @throws IllegalArgumentException if the array is null or the array index |
| 124 | * parameters are not valid |
| 125 | */ |
| 126 | @Override |
| 127 | public double evaluate(final double[] values, final int begin, final int length) { |
| 128 | double max = Double.NaN; |
| 129 | if (test(values, begin, length)) { |
| 130 | max = values[begin]; |
| 131 | for (int i = begin; i < begin + length; i++) { |
| 132 | if (!Double.isNaN(values[i])) { |
| 133 | max = (max > values[i]) ? max : values[i]; |
| 134 | } |
| 135 | } |
| 136 | } |
| 137 | return max; |
| 138 | } |
| 139 | |
| 140 | /** |
| 141 | * {@inheritDoc} |
| 142 | */ |
| 143 | @Override |
| 144 | public Max copy() { |
| 145 | Max result = new Max(); |
| 146 | copy(this, result); |
| 147 | return result; |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * Copies source to dest. |
| 152 | * <p>Neither source nor dest can be null.</p> |
| 153 | * |
| 154 | * @param source Max to copy |
| 155 | * @param dest Max to copy to |
| 156 | * @throws NullPointerException if either source or dest is null |
| 157 | */ |
| 158 | public static void copy(Max source, Max dest) { |
| 159 | dest.setData(source.getDataRef()); |
| 160 | dest.n = source.n; |
| 161 | dest.value = source.value; |
| 162 | } |
| 163 | } |