/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 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.tools.math.optimization.ec.es;

import java.util.LinkedList;
import java.util.List;

import com.rapidminer.tools.RandomGenerator;


/**
 * Checks for each value if it should mutated. Sets a non-min value
 * to min and a min value to a random value between min and max.
 * 
 * @author Ingo Mierswa
 * @version $Id: SparsityMutation.java,v 1.5 2008/05/09 19:23:16 ingomierswa Exp $
 */
public class SparsityMutation implements Mutation {

	private double prob;

	private double[] min, max;

    private OptimizationValueType[] valueTypes;
    
    private RandomGenerator random;
    
    
	public SparsityMutation(double prob, double[] min, double[] max, OptimizationValueType[] valueTypes, RandomGenerator random) {
		this.prob = prob;
		this.min = min;
        this.max = max;
        this.valueTypes = valueTypes;
        this.random = random;
	}

	public void setValueType(int index, OptimizationValueType type) {
		this.valueTypes[index] = type;
	}
	
	public void operate(Population population) {
		List<Individual> newIndividuals = new LinkedList<Individual>();
		for (int i = 0; i < population.getNumberOfIndividuals(); i++) {
			Individual clone = (Individual) population.get(i).clone();
			double[] values = clone.getValues();
			boolean changed = false;
			for (int j = 0; j < values.length; j++) {
				if (random.nextDouble() < prob) {
					changed = true;
					if (values[j] > min[j])
						values[j] = min[j];
					else
						values[j] = random.nextDoubleInRange(min[j], max[j]);
                    if (valueTypes[j].equals(OptimizationValueType.VALUE_TYPE_INT)) {
                        values[j] = (int)Math.round(values[j]);
                    } else if (valueTypes[j].equals(OptimizationValueType.VALUE_TYPE_BOUNDS)) {
                    	if (values[j] >= (max[j] - min[j]) / 2.0d) {
                    		values[j] = min[j];
                    	} else {
                    		values[j] = max[j];
                    	}
                    }
				}
			}
			if (changed) {
				clone.setValues(values);
				newIndividuals.add(clone);
			}
		}
		population.addAll(newIndividuals);
	}
}