org.openimaj.lsh.functions.ShortHashFunctionFactory Maven / Gradle / Ivy

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/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
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package org.openimaj.lsh.functions;

import org.openimaj.feature.ShortFVComparison;
import org.openimaj.util.comparator.DistanceComparator;

import cern.jet.random.engine.MersenneTwister;

/**
 * Base {@link RandomisedHashFunction} for producing hash functions
 * seeded by random numbers.
 * 
 * @author Jonathon Hare ([email protected])
 */
public abstract class ShortHashFunctionFactory
		extends
			RandomisedHashFunctionFactory
{
	protected ShortHashFunctionFactory(int ndims, MersenneTwister rng) {
		super(ndims, rng);
	}

	protected abstract ShortFVComparison fvDistanceFunction();

	@Override
	public final DistanceComparator distanceFunction() {
		final ShortFVComparison dst = fvDistanceFunction();

		return new DistanceComparator() {
			@Override
			public double compare(short[] o1, short[] o2) {
				return dst.compare(o1, o2);
			}

			@Override
			public boolean isDistance() {
				return dst.isDistance();
			}
		};
	}
}