001/*
002        AUTOMATICALLY GENERATED BY jTemp FROM
003        /Users/jsh2/Work/openimaj/target/checkout/machine-learning/nearest-neighbour/src/main/jtemp/org/openimaj/lsh/functions/#T#HashFunctionFactory.jtemp
004*/
005/**
006 * Copyright (c) 2011, The University of Southampton and the individual contributors.
007 * All rights reserved.
008 *
009 * Redistribution and use in source and binary forms, with or without modification,
010 * are permitted provided that the following conditions are met:
011 *
012 *   *  Redistributions of source code must retain the above copyright notice,
013 *      this list of conditions and the following disclaimer.
014 *
015 *   *  Redistributions in binary form must reproduce the above copyright notice,
016 *      this list of conditions and the following disclaimer in the documentation
017 *      and/or other materials provided with the distribution.
018 *
019 *   *  Neither the name of the University of Southampton nor the names of its
020 *      contributors may be used to endorse or promote products derived from this
021 *      software without specific prior written permission.
022 *
023 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
024 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
025 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
026 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
027 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
028 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
029 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
030 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
031 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
032 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
033 */
034package org.openimaj.lsh.functions;
035
036import org.openimaj.feature.DoubleFVComparison;
037import org.openimaj.util.comparator.DistanceComparator;
038
039import cern.jet.random.engine.MersenneTwister;
040
041/**
042 * Base {@link RandomisedHashFunction} for producing hash functions
043 * seeded by random numbers.
044 * 
045 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
046 */
047public abstract class DoubleHashFunctionFactory
048                extends
049                        RandomisedHashFunctionFactory<double[]>
050{
051        protected DoubleHashFunctionFactory(int ndims, MersenneTwister rng) {
052                super(ndims, rng);
053        }
054
055        protected abstract DoubleFVComparison fvDistanceFunction();
056
057        @Override
058        public final DistanceComparator<double[]> distanceFunction() {
059                final DoubleFVComparison dst = fvDistanceFunction();
060
061                return new DistanceComparator<double[]>() {
062                        @Override
063                        public double compare(double[] o1, double[] o2) {
064                                return dst.compare(o1, o2);
065                        }
066
067                        @Override
068                        public boolean isDistance() {
069                                return dst.isDistance();
070                        }
071                };
072        }
073}