001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.math3.optim;
018
019 import java.io.Serializable;
020 import org.apache.commons.math3.util.Pair;
021
022 /**
023 * This class holds a point and the value of an objective function at
024 * that point.
025 *
026 * @see PointVectorValuePair
027 * @see org.apache.commons.math3.analysis.MultivariateFunction
028 * @version $Id: PointValuePair.java 1416643 2012-12-03 19:37:14Z tn $
029 * @since 3.0
030 */
031 public class PointValuePair extends Pair<double[], Double> implements Serializable {
032 /** Serializable UID. */
033 private static final long serialVersionUID = 20120513L;
034
035 /**
036 * Builds a point/objective function value pair.
037 *
038 * @param point Point coordinates. This instance will store
039 * a copy of the array, not the array passed as argument.
040 * @param value Value of the objective function at the point.
041 */
042 public PointValuePair(final double[] point,
043 final double value) {
044 this(point, value, true);
045 }
046
047 /**
048 * Builds a point/objective function value pair.
049 *
050 * @param point Point coordinates.
051 * @param value Value of the objective function at the point.
052 * @param copyArray if {@code true}, the input array will be copied,
053 * otherwise it will be referenced.
054 */
055 public PointValuePair(final double[] point,
056 final double value,
057 final boolean copyArray) {
058 super(copyArray ? ((point == null) ? null :
059 point.clone()) :
060 point,
061 value);
062 }
063
064 /**
065 * Gets the point.
066 *
067 * @return a copy of the stored point.
068 */
069 public double[] getPoint() {
070 final double[] p = getKey();
071 return p == null ? null : p.clone();
072 }
073
074 /**
075 * Gets a reference to the point.
076 *
077 * @return a reference to the internal array storing the point.
078 */
079 public double[] getPointRef() {
080 return getKey();
081 }
082
083 /**
084 * Replace the instance with a data transfer object for serialization.
085 * @return data transfer object that will be serialized
086 */
087 private Object writeReplace() {
088 return new DataTransferObject(getKey(), getValue());
089 }
090
091 /** Internal class used only for serialization. */
092 private static class DataTransferObject implements Serializable {
093 /** Serializable UID. */
094 private static final long serialVersionUID = 20120513L;
095 /**
096 * Point coordinates.
097 * @Serial
098 */
099 private final double[] point;
100 /**
101 * Value of the objective function at the point.
102 * @Serial
103 */
104 private final double value;
105
106 /** Simple constructor.
107 * @param point Point coordinates.
108 * @param value Value of the objective function at the point.
109 */
110 public DataTransferObject(final double[] point, final double value) {
111 this.point = point.clone();
112 this.value = value;
113 }
114
115 /** Replace the deserialized data transfer object with a {@link PointValuePair}.
116 * @return replacement {@link PointValuePair}
117 */
118 private Object readResolve() {
119 return new PointValuePair(point, value, false);
120 }
121 }
122 }