AntQ.java

/*
 * MIT License
 *
 * Copyright (c) 2009-2016 Enrique Areyan <enrique3 at gmail.com>
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package libai.ants.algorithms;

import libai.ants.AntFrameworkException;
import libai.ants.Enviroment;

/**
 * @author enriqueareyan
 */
abstract public class AntQ extends AntColonySystem {

    /**
     * Learning step size
     */
    protected static final int gamma = 10;

    public AntQ(Enviroment E) {
        super(E);
    }

    protected AntQ() {
    }

    @Override
    public void checkParameters() throws AntFrameworkException {
        super.checkParameters();
        /* check obligatory parameters */
        if (!this.Parameters.containsKey(AntQ.gamma)) {
            throw new AntFrameworkException("Parameter gamma must exists");
        }
    }

    public double getMaxNeighbor(int i) {
        int cols = this.Graph.getM().getColumns();
        double max = 0;
        //Calculate adjancent nodes
        for (int j = 0; j < cols; j++) {
            double v = this.Graph.getM().position(i, j);
            if (v < Integer.MAX_VALUE) {
                /* Node i,j are connected */
                if (this.Pheromones.position(i, j) > max) {
                    max = this.Pheromones.position(i, j);
                }
            }
        }
        return max;
    }

    @Override
    public void localPheromonesUpdate(int i, int j) {
        double localRo1 = this.Parameters.get(AntQ.ro_1);
        double localGamma = this.Parameters.get(AntQ.gamma);
        //System.out.println("getMaxNeighbor = "+ getMaxNeighbor(j));
        this.Pheromones.position(i, j, ((1 - localRo1) * this.Pheromones.position(i, j)) + (localRo1 * localGamma * getMaxNeighbor(j)));
    }

    @Override
    public void pheromonesUpdate() {
        /* Update pheromones only on the best tour so far */
        //System.out.println("pheromonesUpdate of the best tour = "+this.bestSolution );
        int node_i = 0, node_j = 0;
        for (int i = 0; i < this.bestSolution.size() - 1; i++) {
            node_i = this.bestSolution.get(i);
            node_j = this.bestSolution.get(i + 1);
            this.Pheromones.increment(node_i, node_j, this.Parameters.get(AntQ.ro_1) * ((1 / f(this.bestSolution)) * getMaxNeighbor(node_j)));
        }
    }
}