ProbabilityFilter.java

Go to the documentation of this file.

/* *********************************************************************** *
 * project: org.matsim.*
 * ProbabilityFilter.java
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 * copyright       : (C) 2013 by the members listed in the COPYING,        *
 *                   LICENSE and WARRANTY file.                            *
 * email           : info at matsim dot org                                *
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *   See also COPYING, LICENSE and WARRANTY file                           *
 *                                                                         *
 * *********************************************************************** */

package org.matsim.withinday.replanning.identifiers.filter;

import java.util.Iterator;
import java.util.Random;
import java.util.Set;

import org.matsim.api.core.v01.Id;
import org.matsim.api.core.v01.population.Person;
import org.matsim.core.gbl.MatsimRandom;
import org.matsim.withinday.replanning.identifiers.interfaces.AgentFilter;

public class ProbabilityFilter implements AgentFilter {

    private final Random random = MatsimRandom.getLocalInstance();
    private final double replanningProbability;
    
    // use the factory
    /*package*/ ProbabilityFilter(double replanningProbability) {
        this.replanningProbability = replanningProbability;
    }
    
    @Override
    public void applyAgentFilter(Set<Id<Person>> set, double time) {
        Iterator<Id<Person>> iter = set.iterator();
        
        while (iter.hasNext()) {
            Id<Person> id = iter.next();
            
            if (!this.applyAgentFilter(id, time)) iter.remove();
        }
    }
    
    @Override
    public boolean applyAgentFilter(Id<Person> id, double time) {
        
        /*
         * This ensures that the filter's outcomes do not depend on the order
         * in which agents are filtered. Otherwise agents stored in unsorted
         * data structures will not produce deterministic outcomes!
         */
        random.setSeed(id.hashCode() + (long) time);
        
        /*
         * Based on a random number it is decided whether an agent should 
         * do a replanning or not.
         * number > replanningProbability: no replanning
         */
        double rand = random.nextDouble();
        if (rand > replanningProbability) return false;
        else return true;
    }
}