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.ml.timeseries.aggregator;
031
032import org.openimaj.math.matrix.MatrixUtils;
033import org.openimaj.ml.timeseries.IncompatibleTimeSeriesException;
034import org.openimaj.ml.timeseries.processor.interpolation.LinearInterpolationProcessor;
035import org.openimaj.ml.timeseries.series.DoubleSynchronisedTimeSeriesCollection;
036import org.openimaj.ml.timeseries.series.DoubleTimeSeries;
037import Jama.Matrix;
038
039public class MeanSquaredDifferenceAggregator implements SynchronisedTimeSeriesCollectionAggregator<DoubleTimeSeries, DoubleSynchronisedTimeSeriesCollection, Double>{
040
041        @Override
042        public Double aggregate(DoubleSynchronisedTimeSeriesCollection series) {
043                Matrix squarediffs = null;
044                int size = 0;
045                for (DoubleTimeSeries ds: series.allseries()) {
046                        if(squarediffs == null){
047                                squarediffs = new Matrix(new double[][]{ds.getData()});
048                        }
049                        else{
050                                squarediffs = squarediffs.minus(new Matrix(new double[][]{ds.getData()}));
051                                squarediffs = squarediffs.arrayTimes(squarediffs );
052                        }
053                        size = ds.size();
054                }
055                return MatrixUtils.sum(squarediffs)/size;
056        }
057
058        public static Double error(DoubleTimeSeries ... series) throws IncompatibleTimeSeriesException {
059                DoubleTimeSeries first = series[0];
060                long[] importantTimes = first.getTimes();
061                DoubleSynchronisedTimeSeriesCollection aaplinterp = new DoubleSynchronisedTimeSeriesCollection();
062                int i = 0;
063                for (DoubleTimeSeries doubleTimeSeries : series) {
064                        if(i!=0){
065                                doubleTimeSeries = doubleTimeSeries.process(new LinearInterpolationProcessor(importantTimes));
066                        }
067                        aaplinterp.addTimeSeries("" + i++, doubleTimeSeries);
068                }
069                return new MeanSquaredDifferenceAggregator().aggregate(aaplinterp);
070        }
071
072}