com.github.rinde.rinsim.scenario.gendreau06.Gendreau06ObjectiveFunction Maven / Gradle / Ivy
/*
* Copyright (C) 2011-2015 Rinde van Lon, iMinds-DistriNet, KU Leuven
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.rinde.rinsim.scenario.gendreau06;
import java.io.Serializable;
import com.github.rinde.rinsim.pdptw.common.ObjectiveFunction;
import com.github.rinde.rinsim.pdptw.common.StatisticsDTO;
/**
* Objective function for Gendreau et al. (2006) problem instances.
* @author Rinde van Lon
*/
public final class Gendreau06ObjectiveFunction implements ObjectiveFunction,
Serializable {
private static final long serialVersionUID = 6069190376442772396L;
private static final Gendreau06ObjectiveFunction INSTANCE = new Gendreau06ObjectiveFunction();
private static final double MS_TO_MINUTES = 60000d;
private static final double ALPHA = 1d;
private static final double BETA = 1d;
private Gendreau06ObjectiveFunction() {}
/**
* All parcels need to be delivered, all vehicles need to be back at the
* depot.
* @param stats The statistics object to check for validity.
* @return true when the statistics object represents a valid
* simulation run, false otherwise.
*/
@Override
public boolean isValidResult(StatisticsDTO stats) {
return stats.totalParcels == stats.acceptedParcels
&& stats.totalParcels == stats.totalPickups
&& stats.totalParcels == stats.totalDeliveries
&& stats.simFinish
&& stats.totalVehicles == stats.vehiclesAtDepot;
}
/**
* Computes the cost according to the definition of the paper: the cost
* function used throughout this work is to minimize a weighted sum of three
* different criteria: total travel time, sum of lateness over all pick-up and
* delivery locations and sum of overtime over all vehicles. The function
* is defined as:
* sum(Tk) + alpha sum(max(0,tv-lv)) + beta sum(max(0,tk-l0))
* Where: Tk is the total travel time on route Rk, alpha and beta are
* weighting parameters which were set to 1 in the paper. The definition of
* lateness: max(0,lateness) is commonly referred to as
* tardiness. All times are expressed in minutes.
* @param stats The statistics object to compute the cost for.
* @return The cost.
*/
@Override
public double computeCost(StatisticsDTO stats) {
final double totalTravelTime = travelTime(stats);
final double sumTardiness = tardiness(stats);
final double overTime = overTime(stats);
return totalTravelTime + ALPHA * sumTardiness + BETA * overTime;
}
@Override
public String printHumanReadableFormat(StatisticsDTO stats) {
return new StringBuilder().append("Travel time: ")
.append(travelTime(stats)).append("\nTardiness: ")
.append(tardiness(stats)).append("\nOvertime: ")
.append(overTime(stats)).append("\nTotal: ").append(computeCost(stats))
.toString();
}
/**
* Computes the travel time based on the {@link StatisticsDTO}.
* @param stats The statistics.
* @return The travel time in minutes.
*/
public double travelTime(StatisticsDTO stats) {
// avg speed is 30 km/h
// = (dist / 30.0) * 60.0
return stats.totalDistance * 2d;
}
/**
* Computes the tardiness based on the {@link StatisticsDTO}.
* @param stats The statistics.
* @return The tardiness in minutes.
*/
public double tardiness(StatisticsDTO stats) {
return (stats.pickupTardiness + stats.deliveryTardiness) / MS_TO_MINUTES;
}
/**
* Computes the over time based on the {@link StatisticsDTO}.
* @param stats The statistics.
* @return The over time in minutes.
*/
public double overTime(StatisticsDTO stats) {
return stats.overTime / MS_TO_MINUTES;
}
@Override
public String toString() {
return this.getClass().getName();
}
/**
* @return The instance.
*/
public static Gendreau06ObjectiveFunction instance() {
return INSTANCE;
}
}