001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.math.statistics.distribution;
031
032import org.openimaj.feature.MultidimensionalDoubleFV;
033
034/**
035 * Simple Histogram based on a MultidimensionalDoubleFV.
036 * 
037 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
038 *
039 */
040public class MultidimensionalHistogram extends MultidimensionalDoubleFV {
041        private static final long serialVersionUID = 1L;
042
043        /**
044         * Construct a histogram with the given number of bins
045         * per dimension.
046         * @param nbins number of bins per dimension
047         */
048        public MultidimensionalHistogram(int... nbins) {
049                super(nbins);
050        }
051
052        /**
053         * Normalise to unit length 
054         */
055        public void normalise() {
056                double sum = 0;
057
058                for (int i=0; i<values.length; i++)
059                        sum += values[i];
060
061                for (int i=0; i<values.length; i++)
062                        values[i] /= sum;
063        }
064        
065        /**
066         * Compute the maximum value in the histogram
067         * @return the maximum value
068         */
069        public double max()
070        {
071                double max = Double.MIN_VALUE;
072                for( int i = 0; i < values.length; i++ )
073                        max = Math.max( values[i], max );
074                return max;
075        }
076        
077        @Override
078        public MultidimensionalHistogram clone() {
079                return (MultidimensionalHistogram) super.clone();
080        }
081}