/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.operator.learner.local;

import java.io.Serializable;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.parameter.ParameterHandler;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeDouble;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Tools;
import com.rapidminer.tools.container.Tupel;
import com.rapidminer.tools.math.container.GeometricDataCollection;

/**
 * This neighborhood includes a fraction of the complete training data set. So the number
 * of nearest neighbors depends on the size of the training set but at least 1.
 * 
 * @author Sebastian Land
 *
 */
public class RelativeNeighborhood implements Neighborhood {
	private static final long serialVersionUID = -3244742069757655400L;

	public static final String PARAMETER_RELATIVE_SIZE = "relative_size";
	
	private double relativeSize;
	
	@Override
	public <T extends Serializable> Collection<Tupel<Double, T>> getNeighbourhood(GeometricDataCollection<T> samples, double[] probePoint) {
		return samples.getNearestValueDistances(Math.max((int) (samples.size() * relativeSize), 1), probePoint);
	}

	@Override
	public List<ParameterType> getParameterTypes(ParameterHandler handler) {
		List<ParameterType> types = new LinkedList<ParameterType>();
		ParameterType type = new ParameterTypeDouble(PARAMETER_RELATIVE_SIZE, "Specifies the size of the neighborhood relative to the total number of examples. A value of 0.04 would include 4% of the data points into the neighborhood.", 0, 1);
		type.setExpert(false);
		types.add(type);
		return types;
	}

	@Override
	public void init(ParameterHandler handler) throws UndefinedParameterError {
		relativeSize = handler.getParameterAsDouble(PARAMETER_RELATIVE_SIZE);
	}

	@Override
	public String toString() {
		return "Relative neighborhood with a fraction of " + Tools.formatNumber(relativeSize, 3) + " of the complete data set";
	}
}