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    
018    package org.apache.commons.math.optimization;
019    
020    import java.io.Serializable;
021    
022    
023    /**
024     * This class holds a point and the value of an objective function at this point.
025     * <p>This is a simple immutable container.</p>
026     * @see VectorialPointValuePair
027     * @see org.apache.commons.math.analysis.MultivariateRealFunction
028     * @version $Id: RealPointValuePair.java 1131229 2011-06-03 20:49:25Z luc $
029     * @since 2.0
030     */
031    public class RealPointValuePair implements Serializable {
032        /** Serializable version identifier. */
033        private static final long serialVersionUID = 1003888396256744753L;
034        /** Point coordinates. */
035        private final double[] point;
036        /** Value of the objective function at the point. */
037        private final double value;
038    
039        /** Build a point/objective function value pair.
040         * @param point point coordinates (the built instance will store
041         * a copy of the array, not the array passed as argument)
042         * @param value value of an objective function at the point
043         */
044        public RealPointValuePair(final double[] point, final double value) {
045            this.point = (point == null) ? null : point.clone();
046            this.value = value;
047        }
048    
049        /** Build a point/objective function value pair.
050         * @param point point coordinates (the built instance will store
051         * a copy of the array, not the array passed as argument)
052         * @param value value of an objective function at the point
053         * @param copyArray if true, the input array will be copied, otherwise
054         * it will be referenced
055         */
056        public RealPointValuePair(final double[] point, final double value,
057                                  final boolean copyArray) {
058            this.point = copyArray ?
059                         ((point == null) ? null : point.clone()) :
060                         point;
061            this.value = value;
062        }
063    
064        /** Get the point.
065         * @return a copy of the stored point
066         */
067        public double[] getPoint() {
068            return (point == null) ? null : point.clone();
069        }
070    
071        /** Get a reference to the point.
072         * <p>This method is provided as a convenience to avoid copying
073         * the array, the elements of the array should <em>not</em> be modified.</p>
074         * @return a reference to the internal array storing the point
075         */
076        public double[] getPointRef() {
077            return point;
078        }
079    
080        /** Get the value of the objective function.
081         * @return the stored value of the objective function
082         */
083        public double getValue() {
084            return value;
085        }
086    }