Time-Dependent Routing Problem with Time Windows (TDCVRPTW)
Problem
In the Time-Dependent Capacitated Vehicle Routing Problem with Time Windows (TDCVRPTW), a fleet of delivery vehicles with uniform capacity must service customers. The customers have known opening hours and demand for a single commodity. The vehicles start and end their routes at a common depot. Each customer must be served by exactly one vehicle within its opening hours, and the total demand served by each vehicle must not exceed its capacity. To model real-world traffic information, the travel time between customers depends on when the travel occurs. The objectives are to minimize the fleet size and the total traveled distance.
In this example, we account for the time-dependent aspect of the model by using multiple constant travel time matrices. We divide the horizon into several time ranges, each with its own travel time matrix for travel starting during this range.
Principles learned
- Add list decision variables to model the trucks’ sequences of customers
- Define an array using a recursive lambda function to compute the customers’ visiting times
- Add multiple objectives and model the lateness as a soft constraint
Data
The instances provided are based on the Solomon CVRPTW instances.
The format of the data files is as follows:
- The first line gives the name of the instance
- The fifth line contains the number of vehicles and their common capacity
- From the 10th line, each line contains the integer data associated with each customer, starting with the depot:
- The index of the customer
- The x coordinate
- The y coordinate
- The demand
- The earliest arrival
- The latest arrival
- The service time
To create TDCVRPTW instances from these CVRPTW instances, we discretize the time horizon into five parts: early morning, morning peak, day, evening peak, and night. For each day part, the travel time between customers is modified according to coefficients depending on distance profiles. The shorter the distance, the more the travel time increases. This is a simple way to create non-proportional travel time matrices, as would be the case with real data.
Program
The Hexaly model for the Time-Dependent Capacitated Vehicle Routing Problem with Time Windows (TDCVRPTW) is an extension of the CVRPTW model. We refer the reader to this model for the routing with time windows aspects of the problem.
To model the time-dependent aspect of the problem, we introduce the timeToMatrixIdx
array, specifying which of the five time periods each time step belongs to, and which time matrix should be used. The travel time matrix then has three dimensions instead of two: the origin customer, the destination customer, and the time period (or index of the matrix to use for this time period). Similarly, we use a two-dimensional matrix to define the travel time to and from the depot.
We write the model for the Time-Dependent Capacitated Vehicle Routing Problem (TDCVRPTW) by modifying the computation of the end times and home lateness defined in the classical CVRPTW model to account for the additional dimension in the matrices.
- Execution
-
hexaly tdcvrptw.hxm inFileName=instances/R101.25.txt [hxTimeLimit=] [solFileName=]
use io;
/* Read instance data. The input files follow the "Solomon" format*/
function input() {
usage = "Usage: hexaly tdcvrptw.hxm "
+ "inFileName=inputFile [solFileName=outputFile] [hxTimeLimit=timeLimit]";
if (inFileName == nil) throw usage;
readInputCvrptw();
computeDistanceMatrices();
}
/* Declare the optimization model */
function model() {
customersSequences[k in 0...nbTrucks] <- list(nbCustomers);
// All customers must be visited by exactly one truck
constraint partition[k in 0...nbTrucks](customersSequences[k]);
for [k in 0...nbTrucks] {
local sequence <- customersSequences[k];
local c <- count(sequence);
// A truck is used if it visits at least one customer
truckUsed[k] <- c > 0;
// The quantity needed in each route must not exceed the truck capacity
routeQuantity[k] <- sum(sequence, j => demands[j]);
constraint routeQuantity[k] <= truckCapacity;
// End of each visit according to the traffic
endTime[k] <- array(0...c, (i, prev) => max(earliestStart[sequence[i]],
i == 0 ? travelTimeWarehouse[sequence[0]][timeToMatrixIdx[0]] :
prev + travelTime[sequence[i-1]][sequence[i]][timeToMatrixIdx[round(prev)]])
+ serviceTime[sequence[i]]);
// Arriving home after max horizon
homeLateness[k] <- truckUsed[k] ? max(0, endTime[k][c-1] +
travelTimeWarehouse[sequence[c-1]][timeToMatrixIdx[round(endTime[k][c-1])]] -
maxHorizon) : 0;
// Distance traveled by truck k
routeDistances[k] <- sum(1...c,
i => distanceMatrix[sequence[i-1]][sequence[i]])
+ (truckUsed[k] ?
(distanceDepot[sequence[0]] + distanceDepot[sequence[c-1]]) :
0);
// Completing visit after latest end
lateness[k] <- homeLateness[k] + sum(0...c,
i => max(0, endTime[k][i] - latestEnd[sequence[i]]));
}
// Total lateness, must be 0 for a solution to be valid
totalLateness <- sum[k in 0...nbTrucks](lateness[k]);
// Total number of trucks used
nbTrucksUsed <- sum[k in 0...nbTrucks](truckUsed[k]);
// Total distance traveled (convention in Solomon's instances is to round to 2 decimals)
totalDistance <- round(100 * sum[k in 0...nbTrucks](routeDistances[k])) / 100;
// Objective: minimize the lateness, then the number of trucks used, then the distance traveled
minimize totalLateness;
minimize nbTrucksUsed;
minimize totalDistance;
}
/* Parameterize the solver */
function param() {
if (hxTimeLimit == nil) hxTimeLimit = 20;
}
/* Write the solution in a file with the following format:
* - number of trucks used and total distance
* - for each truck the customers visited (omitting the start/end at the depot) */
function output() {
if (solFileName == nil) return;
local outfile = io.openWrite(solFileName);
outfile.println(nbTrucksUsed.value, " ", totalDistance.value);
for [k in 0...nbTrucks] {
if (truckUsed[k].value != 1) continue;
for [customer in customersSequences[k].value] {
outfile.print(customer + 1, " ");
}
outfile.println();
}
}
function readInputCvrptw() {
local inFile = io.openRead(inFileName);
skipLines(inFile, 4);
// Truck related data
nbTrucks = inFile.readInt();
truckCapacity = inFile.readInt();
skipLines(inFile, 3);
// Depot data
local line = inFile.readln().split();
depotIndex = line[0].toInt();
depotX = line[1].toInt();
depotY = line[2].toInt();
maxHorizon = line[5].toInt();
// Customers data
i = 0;
while (!inFile.eof()) {
inLine = inFile.readln();
line = inLine.split();
if (count(line) == 0) break;
if (count(line) != 7) throw "Wrong file format";
customerIndex[i] = line[0].toInt();
customerX[i] = line[1].toInt();
customerY[i] = line[2].toInt();
demands[i] = line[3].toInt();
serviceTime[i] = line[6].toInt();
earliestStart[i] = line[4].toInt();
// in input files due date is meant as latest start time
latestEnd[i] = line[5].toInt() + serviceTime[i];
i = i + 1;
}
nbCustomers = i;
inFile.close();
}
function skipLines(inFile, nbLines) {
for [i in 0...nbLines] inFile.readln();
}
// Compute the distance matrices
function computeDistanceMatrices() {
shortDistanceTravelTimeProfile = {1.00, 2.50, 1.75, 2.50, 1.00};
mediumDistanceTravelTimeProfile = {1.00, 2.00, 1.50, 2.00, 1.00};
longDistanceTravelTimeProfile = {1.00, 1.60, 1.10, 1.60, 1.00};
travelTimeProfileMatrix = {
shortDistanceTravelTimeProfile,
mediumDistanceTravelTimeProfile,
longDistanceTravelTimeProfile
};
distanceLevels = {10, 25};
timeIntervalSteps = {0.0, 0.2, 0.4, 0.6, 0.8, 1.0};
nbTimeIntervals = count(timeIntervalSteps)-1;
nbDistanceLevels = count(distanceLevels);
for [i in 0...nbCustomers] {
distanceMatrix[i][i] = 0;
for [k in 0...nbTimeIntervals] {
travelTime[i][i][k] = 0;
}
for [j in i+1...nbCustomers] {
local localDistance = computeDist(i, j);
distanceMatrix[j][i] = localDistance;
distanceMatrix[i][j] = localDistance;
local profileIdx = getProfile(localDistance);
for [k in 0...nbTimeIntervals] {
local localTravelTime = travelTimeProfileMatrix[profileIdx][k] * localDistance;
travelTime[i][j][k] = localTravelTime;
travelTime[j][i][k] = localTravelTime;
}
}
}
for [i in 0...nbTimeIntervals] {
local timeStepStart = round(timeIntervalSteps[i] * maxHorizon);
local timeStepEnd = round(timeIntervalSteps[i+1] * maxHorizon);
for [j in timeStepStart...timeStepEnd+1] {
timeToMatrixIdx[j] = i;
}
}
for [i in 0...nbCustomers] {
local localDistance = computeDepotDist(i);
distanceDepot[i] = localDistance;
local profileIdx = getProfile(localDistance);
for [j in 0...nbTimeIntervals] {
local localTravelTimeWareHouse = travelTimeProfileMatrix[profileIdx][j] * localDistance;
travelTimeWarehouse[i][j] = localTravelTimeWareHouse;
}
}
}
function computeDist(i, j) {
local x1 = customerX[i];
local x2 = customerX[j];
local y1 = customerY[i];
local y2 = customerY[j];
return computeDistance(x1, x2, y1, y2);
}
function computeDepotDist(i) {
local x1 = customerX[i];
local xd = depotX;
local y1 = customerY[i];
local yd = depotY;
return computeDistance(x1, xd, y1, yd);
}
function computeDistance(x1, x2, y1, y2) {
return sqrt(pow((x1 - x2), 2) + pow((y1 - y2), 2));
}
function getProfile(distance) {
local idx = 0;
while (idx < nbDistanceLevels && distance > distanceLevels[idx]) {
idx = idx + 1;
}
return idx;
}
- Execution (Windows)
-
set PYTHONPATH=%HX_HOME%\bin\pythonpython tdcvrptw.py instances\R101.25.txt
- Execution (Linux)
-
export PYTHONPATH=/opt/hexaly_13_0/bin/pythonpython tdcvrptw.py instances/R101.25.txt
import hexaly.optimizer
import sys
import math
def read_elem(filename):
with open(filename) as f:
return [str(elem) for elem in f.read().split()]
def main(instance_file, str_time_limit, output_file):
#
# Read instance data
#
nb_customers, nb_trucks, truck_capacity, dist_matrix_data, travel_time_data, \
time_to_matrix_idx_data, dist_depot_data, travel_time_warehouse_data,\
demands_data, service_time_data, earliest_start_data, latest_end_data, \
max_horizon = read_input_cvrptw(instance_file)
with hexaly.optimizer.HexalyOptimizer() as optimizer:
#
# Declare the optimization model
#
model = optimizer.model
# Sequence of customers visited by each truck
customers_sequences = [model.list(nb_customers) for k in range(nb_trucks)]
# All customers must be visited by exactly one truck
model.constraint(model.partition(customers_sequences))
# Create Hexaly arrays to be able to access them with an "at" operator
demands = model.array(demands_data)
earliest = model.array(earliest_start_data)
latest = model.array(latest_end_data)
service_time = model.array(service_time_data)
dist_matrix = model.array(dist_matrix_data)
travel_time = model.array(travel_time_data)
time_to_matrix_idx = model.array(time_to_matrix_idx_data)
dist_depot = model.array(dist_depot_data)
travel_time_warehouse = model.array(travel_time_warehouse_data)
dist_routes = [None] * nb_trucks
end_time = [None] * nb_trucks
home_lateness = [None] * nb_trucks
lateness = [None] * nb_trucks
# A truck is used if it visits at least one customer
trucks_used = [(model.count(customers_sequences[k]) > 0) for k in range(nb_trucks)]
nb_trucks_used = model.sum(trucks_used)
for k in range(nb_trucks):
sequence = customers_sequences[k]
c = model.count(sequence)
# The quantity needed in each route must not exceed the truck capacity
demand_lambda = model.lambda_function(lambda j: demands[j])
route_quantity = model.sum(sequence, demand_lambda)
model.constraint(route_quantity <= truck_capacity)
# Distance traveled by each truck
dist_lambda = model.lambda_function(
lambda i: model.at(dist_matrix, sequence[i - 1], sequence[i]))
dist_routes[k] = model.sum(model.range(1, c), dist_lambda) \
+ model.iif(c > 0, dist_depot[sequence[0]] + dist_depot[sequence[c - 1]], 0)
# End of each visit according to the traffic
end_time_lambda = model.lambda_function(
lambda i, prev:
model.max(
earliest[sequence[i]],
model.iif(
i == 0, model.at(travel_time_warehouse, sequence[0], time_to_matrix_idx[0]),
prev + model.at(travel_time, sequence[i - 1], sequence[i],
time_to_matrix_idx[model.round(prev)])))
+ service_time[sequence[i]])
end_time[k] = model.array(model.range(0, c), end_time_lambda)
# Arriving home after max horizon
home_lateness[k] = model.iif(
trucks_used[k],
model.max(
0,
end_time[k][c - 1] + model.at(travel_time_warehouse, sequence[c - 1],
time_to_matrix_idx[model.round(end_time[k][c - 1])]) - max_horizon),
0)
# Completing visit after latest end
late_lambda = model.lambda_function(
lambda i: model.max(0, end_time[k][i] - latest[sequence[i]]))
lateness[k] = home_lateness[k] + model.sum(model.range(0, c), late_lambda)
# Total lateness
total_lateness = model.sum(lateness)
# Total distance traveled
total_distance = model.div(model.round(100 * model.sum(dist_routes)), 100)
# Objective: minimize the number of trucks used, then minimize the distance traveled
model.minimize(total_lateness)
model.minimize(nb_trucks_used)
model.minimize(total_distance)
model.close()
# Parameterize the optimizer
optimizer.param.time_limit = int(str_time_limit)
optimizer.solve()
#
# Write the solution in a file with the following format:
# - number of trucks used and total distance
# - for each truck the customers visited (omitting the start/end at the depot)
#
if output_file is not None:
with open(output_file, 'w') as f:
f.write("%d %d\n" % (nb_trucks_used.value, total_distance.value))
for k in range(nb_trucks):
if trucks_used[k].value != 1:
continue
# Values in sequence are in 0...nbCustomers. +1 is to put it back in
# 1...nbCustomers+1 as in the data files (0 being the depot)
for customer in customers_sequences[k].value:
f.write("%d " % (customer + 1))
f.write("\n")
# The input files follow the "Solomon" format
def read_input_cvrptw(filename):
file_it = iter(read_elem(filename))
for i in range(4):
next(file_it)
nb_trucks = int(next(file_it))
truck_capacity = int(next(file_it))
for i in range(13):
next(file_it)
depot_x = int(next(file_it))
depot_y = int(next(file_it))
for i in range(2):
next(file_it)
max_horizon = int(next(file_it))
next(file_it)
customers_x = []
customers_y = []
demands = []
earliest_start = []
latest_end = []
service_time = []
while True:
val = next(file_it, None)
if val is None:
break
i = int(val) - 1
customers_x.append(int(next(file_it)))
customers_y.append(int(next(file_it)))
demands.append(int(next(file_it)))
ready = int(next(file_it))
due = int(next(file_it))
stime = int(next(file_it))
earliest_start.append(ready)
# in input files due date is meant as latest start time
latest_end.append(due + stime)
service_time.append(stime)
nb_customers = i + 1
short_distance_travel_time_profile = [1.00, 2.50, 1.75, 2.50, 1.00]
medium_distance_travel_time_profile = [1.00, 2.00, 1.50, 2.00, 1.00]
long_distance_travel_time_profile = [1.00, 1.60, 1.10, 1.60, 1.00]
travel_time_profile_matrix = [
short_distance_travel_time_profile,
medium_distance_travel_time_profile,
long_distance_travel_time_profile
]
distance_levels = [10, 25]
time_interval_steps = [0.0, 0.2, 0.4, 0.6, 0.8, 1.0]
nb_time_intervals = len(time_interval_steps) - 1
nb_distance_levels = len(distance_levels)
# Compute distance matrices
distance_matrix, travel_time, time_to_matrix_idx = compute_distance_matrices(
customers_x, customers_y, max_horizon, travel_time_profile_matrix, time_interval_steps, nb_time_intervals,
distance_levels, nb_distance_levels)
distance_depots, travel_time_warehouse = compute_distance_depots(
depot_x, depot_y, customers_x, customers_y, travel_time_profile_matrix, nb_time_intervals, distance_levels,
nb_distance_levels)
return nb_customers, nb_trucks, truck_capacity, distance_matrix, travel_time, time_to_matrix_idx, distance_depots, \
travel_time_warehouse, demands, service_time, earliest_start, latest_end, max_horizon
# Computes the distance matrices
def compute_distance_matrices(customers_x, customers_y, max_horizon, travel_time_profile_matrix,
time_interval_steps, nb_time_intervals, distance_levels, nb_distance_levels):
nb_customers = len(customers_x)
distance_matrix = [[None for _ in range(nb_customers)] for _ in range(nb_customers)]
travel_time = [[[None for _ in range(nb_time_intervals)] for _ in range(nb_customers)] for _ in range(nb_customers)]
time_to_matrix_idx = [None for _ in range(max_horizon)]
for i in range(nb_customers):
distance_matrix[i][i] = 0
for k in range(nb_time_intervals):
travel_time[i][i][k] = 0
for j in range(nb_customers):
dist = compute_dist(customers_x[i], customers_x[j],
customers_y[i], customers_y[j])
distance_matrix[i][j] = dist
distance_matrix[j][i] = dist
profile_idx = get_profile(dist, distance_levels, nb_distance_levels)
for k in range(nb_time_intervals):
local_travel_time = travel_time_profile_matrix[profile_idx][k] * dist
travel_time[i][j][k] = local_travel_time
travel_time[j][i][k] = local_travel_time
for i in range(nb_time_intervals):
time_step_start = int(round(time_interval_steps[i] * max_horizon))
time_step_end = int(round(time_interval_steps[i+1] * max_horizon))
for j in range(time_step_start, time_step_end):
time_to_matrix_idx[j] = i
return distance_matrix, travel_time, time_to_matrix_idx
# Computes the distances to depot
def compute_distance_depots(depot_x, depot_y, customers_x, customers_y, travel_time_profile_matrix,
nb_time_intervals, distance_levels, nb_distance_levels):
nb_customers = len(customers_x)
distance_depots = [None] * nb_customers
travel_time_warehouse = [[None for _ in range(nb_time_intervals)] for _ in range(nb_customers)]
for i in range(nb_customers):
dist = compute_dist(depot_x, customers_x[i], depot_y, customers_y[i])
distance_depots[i] = dist
profile_idx = get_profile(dist, distance_levels, nb_distance_levels)
for j in range(nb_time_intervals):
local_travel_time_warehouse = travel_time_profile_matrix[profile_idx][j] * dist
travel_time_warehouse[i][j] = local_travel_time_warehouse
return distance_depots, travel_time_warehouse
def compute_dist(xi, xj, yi, yj):
return math.sqrt(math.pow(xi - xj, 2) + math.pow(yi - yj, 2))
def get_profile(dist, distance_levels, nb_distance_levels):
idx = 0
while idx < nb_distance_levels and dist > distance_levels[idx]:
idx += 1
return idx
if __name__ == '__main__':
if len(sys.argv) < 2:
print("Usage: python tdcvrptw.py input_file [output_file] [time_limit]")
sys.exit(1)
instance_file = sys.argv[1]
output_file = sys.argv[2] if len(sys.argv) > 2 else None
str_time_limit = sys.argv[3] if len(sys.argv) > 3 else "20"
main(instance_file, str_time_limit, output_file)
- Compilation / Execution (Windows)
-
cl /EHsc tdcvrptw.cpp -I%HX_HOME%\include /link %HX_HOME%\bin\hexaly130.libtdcvrptw instances\R101.25.txt
- Compilation / Execution (Linux)
-
g++ tdcvrptw.cpp -I/opt/hexaly_13_0/include -lhexaly130 -lpthread -o tdcvrptw./tdcvrptw instances/R101.25.txt
#include "optimizer/hexalyoptimizer.h"
#include <cmath>
#include <cstring>
#include <fstream>
#include <iostream>
#include <vector>
using namespace hexaly;
using namespace std;
class Tdcvrptw {
public:
// Hexaly Optimizer
HexalyOptimizer optimizer;
// Number of customers
int nbCustomers;
// Capacity of the trucks
int truckCapacity;
// Latest allowed arrival to depot
int maxHorizon;
// Demand for each customer
vector<int> demandsData;
// Earliest arrival for each customer
vector<int> earliestStartData;
// Latest departure from each customer
vector<int> latestEndData;
// Service time for each customer
vector<int> serviceTimeData;
// Distance matrix between customers
vector<vector<double>> distMatrixData;
// Distance between customers and depot
vector<double> distDepotData;
// Travel time coefficients for each profile
vector<double> shortDistanceTravelTimeProfile{1.00, 2.50, 1.75, 2.50, 1.00};
vector<double> mediumDistanceTravelTimeProfile{1.00, 2.00, 1.50, 2.00, 1.00};
vector<double> longDistanceTravelTimeProfile{1.00, 1.60, 1.10, 1.60, 1.00};
vector<vector<double>> travelTimeProfileMatrix{shortDistanceTravelTimeProfile, mediumDistanceTravelTimeProfile,
longDistanceTravelTimeProfile};
// Distance levels
vector<int> distanceLevels{10, 25};
// Intervals of the temporal discretization
vector<double> timeIntervalSteps{0.0, 0.2, 0.4, 0.6, 0.8, 1.0};
// Number of time intervals
int nbTimeIntervals = timeIntervalSteps.size() - 1;
// Number of distance levels
int nbDistanceLevels = distanceLevels.size();
// Travel time between customers for each day part
vector<vector<vector<double>>> travelTimeData;
// Time interval index for each time unit
vector<int> timeToMatrixIdxData;
// Travel time between customers and depot for each day part
vector<vector<double>> travelTimeWarehouseData;
// Number of trucks
int nbTrucks;
// Decision variables
vector<HxExpression> customersSequences;
// Are the trucks actually used
vector<HxExpression> trucksUsed;
// Cumulated lateness in the solution (must be 0 for the solution to be valid)
HxExpression totalLateness;
// Number of trucks used in the solution
HxExpression nbTrucksUsed;
// Distance traveled by all the trucks
HxExpression totalDistance;
Tdcvrptw() {}
/* Read instance data */
void readInstance(const string& fileName) { readInputCvrptw(fileName); }
void solve(int limit) {
// Declare the optimization model
HxModel model = optimizer.getModel();
// Sequence of customers visited by each truck
customersSequences.resize(nbTrucks);
for (int k = 0; k < nbTrucks; ++k) {
customersSequences[k] = model.listVar(nbCustomers);
}
// All customers must be visited by exactly one truck
model.constraint(model.partition(customersSequences.begin(), customersSequences.end()));
// Create Hexaly arrays to be able to access them with an "at" operator
HxExpression demands = model.array(demandsData.begin(), demandsData.end());
HxExpression earliest = model.array(earliestStartData.begin(), earliestStartData.end());
HxExpression latest = model.array(latestEndData.begin(), latestEndData.end());
HxExpression serviceTime = model.array(serviceTimeData.begin(), serviceTimeData.end());
HxExpression distMatrix = model.array();
for (int n = 0; n < nbCustomers; ++n) {
distMatrix.addOperand(model.array(distMatrixData[n].begin(), distMatrixData[n].end()));
}
HxExpression travelTime = model.array();
for (int n = 0; n < nbCustomers; ++n) {
HxExpression timeMatrix = model.array();
for (int m = 0; m < nbCustomers; ++m) {
timeMatrix.addOperand(model.array(travelTimeData[n][m].begin(), travelTimeData[n][m].end()));
}
travelTime.addOperand(timeMatrix);
}
HxExpression timeToMatrixIdx = model.array(timeToMatrixIdxData.begin(), timeToMatrixIdxData.end());
HxExpression distDepot = model.array(distDepotData.begin(), distDepotData.end());
HxExpression travelTimeWarehouse = model.array();
for (int n = 0; n < nbCustomers; ++n) {
travelTimeWarehouse.addOperand(
model.array(travelTimeWarehouseData[n].begin(), travelTimeWarehouseData[n].end()));
}
trucksUsed.resize(nbTrucks);
vector<HxExpression> distRoutes(nbTrucks), endTime(nbTrucks), homeLateness(nbTrucks), lateness(nbTrucks);
for (int k = 0; k < nbTrucks; ++k) {
HxExpression sequence = customersSequences[k];
HxExpression c = model.count(sequence);
// A truck is used if it visits at least one customer
trucksUsed[k] = c > 0;
// The quantity needed in each route must not exceed the truck capacity
HxExpression demandLambda =
model.createLambdaFunction([&](HxExpression j) { return demands[j]; });
HxExpression routeQuantity = model.sum(sequence, demandLambda);
model.constraint(routeQuantity <= truckCapacity);
// Distance traveled by truck k
HxExpression distLambda = model.createLambdaFunction(
[&](HxExpression i) { return model.at(distMatrix, sequence[i - 1], sequence[i]); });
distRoutes[k] = model.sum(model.range(1, c), distLambda) +
model.iif(c > 0, distDepot[sequence[0]] + distDepot[sequence[c - 1]], 0);
// End of each visit according to the traffic
HxExpression endTimeLambda = model.createLambdaFunction([&](HxExpression i, HxExpression prev) {
return model.max(earliest[sequence[i]],
model.iif(i == 0, model.at(travelTimeWarehouse, sequence[0], timeToMatrixIdx[0]),
prev + model.at(travelTime, sequence[i - 1], sequence[i],
timeToMatrixIdx[model.round(prev)]))) +
serviceTime[sequence[i]];
});
endTime[k] = model.array(model.range(0, c), endTimeLambda);
// Arriving home after max horizon
homeLateness[k] = model.iif(trucksUsed[k],
model.max(0, endTime[k][c - 1] +
model.at(travelTimeWarehouse, sequence[c - 1],
timeToMatrixIdx[model.round(endTime[k][c - 1])]) -
maxHorizon),
0);
// Completing visit after latest end
HxExpression lateLambda = model.createLambdaFunction(
[&](HxExpression i) { return model.max(0, endTime[k][i] - latest[sequence[i]]); });
lateness[k] = homeLateness[k] + model.sum(model.range(0, c), lateLambda);
}
// Total lateness
totalLateness = model.sum(lateness.begin(), lateness.end());
// Total number of trucks used
nbTrucksUsed = model.sum(trucksUsed.begin(), trucksUsed.end());
// Total distance traveled (convention in Solomon's instances is to round to 2 decimals)
totalDistance = model.round(100 * model.sum(distRoutes.begin(), distRoutes.end())) / 100;
// Objective: minimize the lateness, then the number of trucks used, then the distance traveled
model.minimize(totalLateness);
model.minimize(nbTrucksUsed);
model.minimize(totalDistance);
model.close();
// Parameterize the optimizer
optimizer.getParam().setTimeLimit(limit);
optimizer.solve();
}
/* Write the solution in a file with the following format:
* - number of trucks used and total distance
* - for each truck the customers visited (omitting the start/end at the depot) */
void writeSolution(const string& fileName) {
ofstream outfile;
outfile.exceptions(ofstream::failbit | ofstream::badbit);
outfile.open(fileName.c_str());
outfile << nbTrucksUsed.getValue() << " " << totalDistance.getDoubleValue() << endl;
for (int k = 0; k < nbTrucks; ++k) {
if (trucksUsed[k].getValue() != 1)
continue;
// Values in sequence are in 0...nbCustomers. +1 is to put it back in 1...nbCustomers+1
// as in the data files (0 being the depot)
HxCollection customersCollection = customersSequences[k].getCollectionValue();
for (int i = 0; i < customersCollection.count(); ++i) {
outfile << customersCollection[i] + 1 << " ";
}
outfile << endl;
}
}
private:
// The input files follow the "Solomon" format
void readInputCvrptw(const string& fileName) {
ifstream infile(fileName.c_str());
if (!infile.is_open()) {
throw std::runtime_error("File cannot be opened.");
}
string str;
long tmp;
int depotX, depotY;
vector<int> customersX;
vector<int> customersY;
getline(infile, str);
getline(infile, str);
getline(infile, str);
getline(infile, str);
infile >> nbTrucks;
infile >> truckCapacity;
getline(infile, str);
getline(infile, str);
getline(infile, str);
getline(infile, str);
infile >> tmp;
infile >> depotX;
infile >> depotY;
infile >> tmp;
infile >> tmp;
infile >> maxHorizon;
infile >> tmp;
while (infile >> tmp) {
int cx, cy, demand, ready, due, service;
infile >> cx;
infile >> cy;
infile >> demand;
infile >> ready;
infile >> due;
infile >> service;
customersX.push_back(cx);
customersY.push_back(cy);
demandsData.push_back(demand);
earliestStartData.push_back(ready);
latestEndData.push_back(due + service); // in input files due date is meant as latest start time
serviceTimeData.push_back(service);
}
nbCustomers = customersX.size();
computeDistanceMatrix(depotX, depotY, customersX, customersY);
infile.close();
}
// Compute the distance matrix
void computeDistanceMatrix(int depotX, int depotY, const vector<int>& customersX, const vector<int>& customersY) {
distMatrixData.resize(nbCustomers);
travelTimeData.resize(nbCustomers);
timeToMatrixIdxData.resize(maxHorizon);
travelTimeWarehouseData.resize(nbCustomers);
for (int i = 0; i < nbCustomers; ++i) {
distMatrixData[i].resize(nbCustomers);
travelTimeData[i].resize(nbCustomers);
for (int j = 0; j < nbCustomers; ++j) {
travelTimeData[i][j].resize(nbTimeIntervals);
}
}
for (int i = 0; i < nbCustomers; ++i) {
travelTimeWarehouseData[i].resize(nbTimeIntervals);
}
for (int i = 0; i < nbCustomers; ++i) {
distMatrixData[i][i] = 0;
for (int k = 0; k < nbTimeIntervals; ++k) {
travelTimeData[i][i][k] = 0;
}
for (int j = i + 1; j < nbCustomers; ++j) {
double distance = computeDist(customersX[i], customersX[j], customersY[i], customersY[j]);
distMatrixData[i][j] = distance;
distMatrixData[j][i] = distance;
int profileIdx = getProfile(distance);
for (int k = 0; k < nbTimeIntervals; ++k) {
double localTravelTime = travelTimeProfileMatrix[profileIdx][k] * distance;
travelTimeData[i][j][k] = localTravelTime;
travelTimeData[j][i][k] = localTravelTime;
}
}
}
for (int i = 0; i < nbTimeIntervals; ++i) {
int timeStepStart = (int)round(timeIntervalSteps[i] * maxHorizon);
int timeStepEnd = (int)round(timeIntervalSteps[i + 1] * maxHorizon);
for (int j = timeStepStart; j < timeStepEnd; ++j) {
timeToMatrixIdxData[j] = i;
}
}
distDepotData.resize(nbCustomers);
for (int i = 0; i < nbCustomers; ++i) {
double distance = computeDist(depotX, customersX[i], depotY, customersY[i]);
distDepotData[i] = distance;
int profileIdx = getProfile(distance);
for (int j = 0; j < nbTimeIntervals; ++j) {
double localTravelTimeWarehouse = travelTimeProfileMatrix[profileIdx][j] * distance;
travelTimeWarehouseData[i][j] = localTravelTimeWarehouse;
}
}
}
double computeDist(int xi, int xj, int yi, int yj) {
return sqrt(pow((double)xi - xj, 2) + pow((double)yi - yj, 2));
}
int getProfile(double distance) {
int idx = 0;
while (idx < nbDistanceLevels && distance > distanceLevels[idx]) {
idx += 1;
}
return idx;
}
};
int main(int argc, char** argv) {
if (argc < 2) {
cerr << "Usage: tdcvrptw inputFile [outputFile] [timeLimit] [nbTrucks]" << endl;
return 1;
}
const char* instanceFile = argv[1];
const char* solFile = argc > 2 ? argv[2] : NULL;
const char* strTimeLimit = argc > 3 ? argv[3] : "20";
try {
Tdcvrptw model;
model.readInstance(instanceFile);
model.solve(atoi(strTimeLimit));
if (solFile != NULL)
model.writeSolution(solFile);
return 0;
} catch (const exception& e) {
cerr << "An error occurred: " << e.what() << endl;
return 1;
}
}
- Compilation / Execution (Windows)
-
copy %HX_HOME%\bin\Hexaly.NET.dll .csc Tdcvrptw.cs /reference:Hexaly.NET.dllTdcvrptw instances\R101.25.txt
using System;
using System.IO;
using System.Collections.Generic;
using Hexaly.Optimizer;
public class Tdcvrptw : IDisposable
{
// Hexaly Optimizer
HexalyOptimizer optimizer;
// Number of customers
int nbCustomers;
// Capacity of the trucks
int truckCapacity;
// Latest allowed arrival to depot
int maxHorizon;
// Demand for each customer
List<int> demandsData;
// Earliest arrival for each customer
List<int> earliestStartData;
// Latest departure from each customer
List<int> latestEndData;
// Service time for each customer
List<int> serviceTimeData;
// Distance matrix between customers
double[][] distMatrixData;
// Distances between customers and depot
double[] distDepotData;
// Travel time coefficients for each profile
static double[] shortDistanceTravelTimeProfile = { 1.00, 2.50, 1.75, 2.50, 1.00 };
static double[] mediumDistanceTravelTimeProfile = { 1.00, 2.00, 1.50, 2.00, 1.00 };
static double[] longDistanceTravelTimeProfile = { 1.00, 1.60, 1.10, 1.60, 1.00 };
static double[][] travelTimeProfileMatrix =
{
shortDistanceTravelTimeProfile,
mediumDistanceTravelTimeProfile,
longDistanceTravelTimeProfile
};
// Distance levels
static int[] distanceLevels = { 10, 25 };
// Intervals of the temporal discretization
static double[] timeIntervalSteps = { 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 };
// Number of time intervals
static int nbTimeIntervals = timeIntervalSteps.Length - 1;
// Number of distances levels
static int nbDistanceLevels = distanceLevels.Length;
// Travel time between customers for each day part
double[][][] travelTimeData;
// Time interval index for each time unit
int[] timeToMatrixIdxData;
// Travel time between customers and depot for each day part
double[][] travelTimeWarehouseData;
// Number of trucks
int nbTrucks;
// Decision variables
HxExpression[] customersSequences;
// Are the trucks actually used
HxExpression[] trucksUsed;
// Cumulated lateness in the solution (must be 0 for the solution to be valid)
HxExpression totalLateness;
// Number of trucks used in the solution
HxExpression nbTrucksUsed;
// Distance traveled by all the trucks
HxExpression totalDistance;
public Tdcvrptw()
{
optimizer = new HexalyOptimizer();
}
/* Read instance data */
void ReadInstance(string fileName)
{
ReadInputCvrptw(fileName);
}
public void Dispose()
{
if (optimizer != null)
optimizer.Dispose();
}
void Solve(int limit)
{
// Declare the optimization model
HxModel model = optimizer.GetModel();
trucksUsed = new HxExpression[nbTrucks];
customersSequences = new HxExpression[nbTrucks];
HxExpression[] distRoutes = new HxExpression[nbTrucks];
HxExpression[] endTime = new HxExpression[nbTrucks];
HxExpression[] homeLateness = new HxExpression[nbTrucks];
HxExpression[] lateness = new HxExpression[nbTrucks];
// Sequence of customers visited by each truck
for (int k = 0; k < nbTrucks; ++k)
customersSequences[k] = model.List(nbCustomers);
// All customers must be visited by exactly one truck
model.Constraint(model.Partition(customersSequences));
// Create HexalyOptimizer arrays to be able to access them with an "at" operator
HxExpression demands = model.Array(demandsData);
HxExpression earliest = model.Array(earliestStartData);
HxExpression latest = model.Array(latestEndData);
HxExpression serviceTime = model.Array(serviceTimeData);
HxExpression distDepot = model.Array(distDepotData);
HxExpression distMatrix = model.Array(distMatrixData);
HxExpression travelTime = model.Array(travelTimeData);
HxExpression timeToMatrixIdx = model.Array(timeToMatrixIdxData);
HxExpression travelTimeWarehouse = model.Array(travelTimeWarehouseData);
for (int k = 0; k < nbTrucks; ++k)
{
HxExpression sequence = customersSequences[k];
HxExpression c = model.Count(sequence);
// A truck is used if it visits at least one customer
trucksUsed[k] = c > 0;
// The quantity needed in each route must not exceed the truck capacity
HxExpression demandLambda = model.LambdaFunction(j => demands[j]);
HxExpression routeQuantity = model.Sum(sequence, demandLambda);
model.Constraint(routeQuantity <= truckCapacity);
// Distance traveled by truck k
HxExpression distLambda = model.LambdaFunction(
i => distMatrix[sequence[i - 1], sequence[i]]
);
distRoutes[k] =
model.Sum(model.Range(1, c), distLambda)
+ model.If(c > 0, distDepot[sequence[0]] + distDepot[sequence[c - 1]], 0);
// End of each visit according to the traffic
HxExpression endTimeLambda = model.LambdaFunction(
(i, prev) =>
model.Max(
earliest[sequence[i]],
model.If(
i == 0,
travelTimeWarehouse[sequence[0], timeToMatrixIdx[0]],
prev
+ model.At(
travelTime,
sequence[i - 1],
sequence[i],
timeToMatrixIdx[model.Round(prev)]
)
)
) + serviceTime[sequence[i]]
);
endTime[k] = model.Array(model.Range(0, c), endTimeLambda);
// Arriving home after max_horizon
homeLateness[k] = model.If(
trucksUsed[k],
model.Max(
0,
endTime[k][c - 1]
+ travelTimeWarehouse[
sequence[c - 1],
timeToMatrixIdx[model.Round(endTime[k][c - 1])]
]
- maxHorizon
),
0
);
// Completing visit after latest_end
HxExpression lateLambda = model.LambdaFunction(
i => model.Max(endTime[k][i] - latest[sequence[i]], 0)
);
lateness[k] = homeLateness[k] + model.Sum(model.Range(0, c), lateLambda);
}
// Total lateness
totalLateness = model.Sum(lateness);
// Total number of trucks used
nbTrucksUsed = model.Sum(trucksUsed);
// Total distance traveled (convention in Solomon's instances is to round to 2 decimals)
totalDistance = model.Round(100 * model.Sum(distRoutes)) / 100;
// Objective: minimize the lateness, then the number of trucks used, then the distance traveled
model.Minimize(totalLateness);
model.Minimize(nbTrucksUsed);
model.Minimize(totalDistance);
model.Close();
// Parameterize the optimizer
optimizer.GetParam().SetTimeLimit(limit);
optimizer.Solve();
}
/* Write the solution in a file with the following format:
* - number of trucks used and total distance
* - for each truck the customers visited (omitting the start/end at the depot) */
void WriteSolution(string fileName)
{
using (StreamWriter output = new StreamWriter(fileName))
{
output.WriteLine(nbTrucksUsed.GetValue() + " " + totalDistance.GetDoubleValue());
for (int k = 0; k < nbTrucks; ++k)
{
if (trucksUsed[k].GetValue() != 1)
continue;
// Values in sequence are in 0...nbCustomers. +1 is to put it back in 1...nbCustomers+1
// as in the data files (0 being the depot)
HxCollection customersCollection = customersSequences[k].GetCollectionValue();
for (int i = 0; i < customersCollection.Count(); ++i)
output.Write((customersCollection[i] + 1) + " ");
output.WriteLine();
}
}
}
public static void Main(string[] args)
{
if (args.Length < 1)
{
Console.WriteLine("Usage: Tdcvrptw inputFile [solFile] [timeLimit]");
Environment.Exit(1);
}
string instanceFile = args[0];
string outputFile = args.Length > 1 ? args[1] : null;
string strTimeLimit = args.Length > 2 ? args[2] : "20";
using (Tdcvrptw model = new Tdcvrptw())
{
model.ReadInstance(instanceFile);
model.Solve(int.Parse(strTimeLimit));
if (outputFile != null)
model.WriteSolution(outputFile);
}
}
string[] SplitInput(StreamReader input)
{
string line = input.ReadLine();
if (line == null)
return new string[0];
return line.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
}
// The input files follow the "Solomon" format
void ReadInputCvrptw(string fileName)
{
using (StreamReader input = new StreamReader(fileName))
{
string[] splitted;
input.ReadLine();
input.ReadLine();
input.ReadLine();
input.ReadLine();
splitted = SplitInput(input);
nbTrucks = int.Parse(splitted[0]);
truckCapacity = int.Parse(splitted[1]);
input.ReadLine();
input.ReadLine();
input.ReadLine();
input.ReadLine();
splitted = SplitInput(input);
int depotX = int.Parse(splitted[1]);
int depotY = int.Parse(splitted[2]);
maxHorizon = int.Parse(splitted[5]);
List<int> customersX = new List<int>();
List<int> customersY = new List<int>();
demandsData = new List<int>();
earliestStartData = new List<int>();
latestEndData = new List<int>();
serviceTimeData = new List<int>();
while (!input.EndOfStream)
{
splitted = SplitInput(input);
if (splitted.Length < 7)
break;
customersX.Add(int.Parse(splitted[1]));
customersY.Add(int.Parse(splitted[2]));
demandsData.Add(int.Parse(splitted[3]));
int ready = int.Parse(splitted[4]);
int due = int.Parse(splitted[5]);
int service = int.Parse(splitted[6]);
earliestStartData.Add(ready);
latestEndData.Add(due + service); // in input files due date is meant as latest start time
serviceTimeData.Add(service);
}
nbCustomers = customersX.Count;
ComputeDistanceMatrix(depotX, depotY, customersX, customersY);
}
}
// Compute the distance matrix
void ComputeDistanceMatrix(int depotX, int depotY, List<int> customersX, List<int> customersY)
{
distMatrixData = new double[nbCustomers][];
travelTimeData = new double[nbCustomers][][];
timeToMatrixIdxData = new int[maxHorizon];
travelTimeWarehouseData = new double[nbCustomers][];
for (int i = 0; i < nbCustomers; ++i)
{
distMatrixData[i] = new double[nbCustomers];
double[][] timeMatrix = new double[nbCustomers][];
for (int j = 0; j < nbCustomers; ++j)
timeMatrix[j] = new double[nbTimeIntervals];
travelTimeData[i] = timeMatrix;
}
for (int i = 0; i < nbCustomers; ++i)
travelTimeWarehouseData[i] = new double[nbTimeIntervals];
for (int i = 0; i < nbCustomers; ++i)
{
distMatrixData[i][i] = 0;
for (int k = 0; k < nbTimeIntervals; ++k)
travelTimeData[i][i][k] = 0;
for (int j = i + 1; j < nbCustomers; ++j)
{
double dist = ComputeDist(
customersX[i],
customersX[j],
customersY[i],
customersY[j]
);
distMatrixData[i][j] = dist;
distMatrixData[j][i] = dist;
int profileIdx = GetProfile(dist);
for (int k = 0; k < nbTimeIntervals; ++k)
{
double localTravelTime = travelTimeProfileMatrix[profileIdx][k] * dist;
travelTimeData[i][j][k] = localTravelTime;
travelTimeData[j][i][k] = localTravelTime;
}
}
}
for (int i = 0; i < nbTimeIntervals; ++i)
{
int timeStepStart = (int)Math.Round(timeIntervalSteps[i] * maxHorizon);
int timeStepEnd = (int)Math.Round(timeIntervalSteps[i + 1] * maxHorizon);
for (int j = timeStepStart; j < timeStepEnd; ++j)
timeToMatrixIdxData[j] = i;
}
distDepotData = new double[nbCustomers];
for (int i = 0; i < nbCustomers; ++i)
{
double dist = ComputeDist(depotX, customersX[i], depotY, customersY[i]);
distDepotData[i] = dist;
int profileIdx = GetProfile(dist);
for (int j = 0; j < nbTimeIntervals; ++j)
{
double localTravelTimeWarehouse = travelTimeProfileMatrix[profileIdx][j] * dist;
travelTimeWarehouseData[i][j] = localTravelTimeWarehouse;
}
}
}
double ComputeDist(int xi, int xj, int yi, int yj)
{
return Math.Sqrt(Math.Pow(xi - xj, 2) + Math.Pow(yi - yj, 2));
}
int GetProfile(double dist)
{
int idx = 0;
while (idx < nbDistanceLevels && dist > distanceLevels[idx])
idx += 1;
return idx;
}
}
- Compilation / Execution (Windows)
-
javac Tdcvrptw.java -cp %HX_HOME%\bin\hexaly.jarjava -cp %HX_HOME%\bin\hexaly.jar;. Tdcvrptw instances\R101.25.txt
- Compilation / Execution (Linux)
-
javac Tdcvrptw.java -cp /opt/hexaly_13_0/bin/hexaly.jarjava -cp /opt/hexaly_13_0/bin/hexaly.jar:. Tdcvrptw instances\R101.25.txt
import java.util.*;
import java.io.*;
import com.hexaly.optimizer.*;
public class Tdcvrptw {
// Hexaly Optimizer
private final HexalyOptimizer optimizer;
// Number of customers
int nbCustomers;
// Capacity of the trucks
private int truckCapacity;
// Latest allowed arrival to depot
int maxHorizon;
// Demand for each customer
List<Integer> demandsData;
// Earliest arrival for each customer
List<Integer> earliestStartData;
// Latest departure from each customer
List<Integer> latestEndData;
// Service time for each customer
List<Integer> serviceTimeData;
// Distance matrix
private double[][] distMatrixData;
// Distances between customers and depot
private double[] distDepotData;
// Travel time coefficients for each profile
private static double shortDistanceTravelTimeProfile[] = { 1.00, 2.50, 1.75, 2.50, 1.00 };
private static double mediumDistanceTravelTimeProfile[] = { 1.00, 2.00, 1.50, 2.00, 1.00 };
private static double longDistanceTravelTimeProfile[] = { 1.00, 1.60, 1.10, 1.60, 1.00 };
private static double[] travelTimeProfileMatrix[] = {
shortDistanceTravelTimeProfile,
mediumDistanceTravelTimeProfile,
longDistanceTravelTimeProfile
};
// Distance levels
private static int distanceLevels[] = { 10, 25 };
// Intervals of the temporal discretization
private static double timeIntervalSteps[] = { 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 };
// Number of time intervals
private static int nbTimeIntervals = timeIntervalSteps.length - 1;
// Number of distances levels
private static int nbDistanceLevels = distanceLevels.length;
// Travel time between customers for each day part
private double[][][] travelTimeData;
// Time interval index for each time unit
private int[] timeToMatrixIdxData;
// Travel time between customers and depot for each day part
private double[][] travelTimeWarehouseData;
// Number of trucks
private int nbTrucks;
// Decision variables
private HxExpression[] customersSequences;
// Are the trucks actually used
private HxExpression[] trucksUsed;
// Distance traveled by each truck
private HxExpression[] distRoutes;
// End time array for each truck
private HxExpression[] endTime;
// Home lateness for each truck
private HxExpression[] homeLateness;
// Cumulated Lateness for each truck
private HxExpression[] lateness;
// Cumulated lateness in the solution (must be 0 for the solution to be valid)
private HxExpression totalLateness;
// Number of trucks used in the solution
private HxExpression nbTrucksUsed;
// Distance traveled by all the trucks
private HxExpression totalDistance;
private Tdcvrptw(HexalyOptimizer optimizer) {
this.optimizer = optimizer;
}
/* Read instance data */
private void readInstance(String fileName) throws IOException {
readInputCvrptw(fileName);
}
private void solve(int limit) {
// Declare the optimization model
HxModel m = optimizer.getModel();
trucksUsed = new HxExpression[nbTrucks];
customersSequences = new HxExpression[nbTrucks];
distRoutes = new HxExpression[nbTrucks];
endTime = new HxExpression[nbTrucks];
homeLateness = new HxExpression[nbTrucks];
lateness = new HxExpression[nbTrucks];
// Sequence of customers visited by each truck.
for (int k = 0; k < nbTrucks; ++k)
customersSequences[k] = m.listVar(nbCustomers);
// All customers must be visited by exactly one truck
m.constraint(m.partition(customersSequences));
// Create HexalyOptimizer arrays to be able to access them with an "at" operator
HxExpression demands = m.array(demandsData);
HxExpression earliest = m.array(earliestStartData);
HxExpression latest = m.array(latestEndData);
HxExpression serviceTime = m.array(serviceTimeData);
HxExpression distDepot = m.array(distDepotData);
HxExpression distMatrix = m.array(distMatrixData);
HxExpression travelTime = m.array(travelTimeData);
HxExpression timeToMatrixIdx = m.array(timeToMatrixIdxData);
HxExpression travelTimeWarehouse = m.array(travelTimeWarehouseData);
for (int k = 0; k < nbTrucks; ++k) {
HxExpression sequence = customersSequences[k];
HxExpression c = m.count(sequence);
// A truck is used if it visits at least one customer
trucksUsed[k] = m.gt(c, 0);
// The quantity needed in each route must not exceed the truck capacity
HxExpression demandLambda = m.lambdaFunction(j -> m.at(demands, j));
HxExpression routeQuantity = m.sum(sequence, demandLambda);
m.constraint(m.leq(routeQuantity, truckCapacity));
// Distance traveled by truck k
HxExpression distLambda = m
.lambdaFunction(i -> m.at(distMatrix, m.at(sequence, m.sub(i, 1)), m.at(sequence, i)));
distRoutes[k] = m.sum(m.sum(m.range(1, c), distLambda), m.iif(m.gt(c, 0),
m.sum(m.at(distDepot, m.at(sequence, 0)), m.at(distDepot, m.at(sequence, m.sub(c, 1)))), 0));
// End of each visit according to the traffic
HxExpression endTimeLambda = m.lambdaFunction((i, prev) -> m.sum(
m.max(m.at(earliest, m.at(sequence, i)),
m.sum(m.iif(m.eq(i, 0),
m.at(travelTimeWarehouse, m.at(sequence, 0), m.at(timeToMatrixIdx, 0)),
m.sum(prev, m.at(travelTime, m.at(sequence, m.sub(i, 1)), m.at(sequence, i),
m.at(timeToMatrixIdx, m.round(prev))))))),
m.at(serviceTime, m.at(sequence, i))));
endTime[k] = m.array(m.range(0, c), endTimeLambda);
HxExpression theEnd = endTime[k];
// Arriving home after max_horizon
homeLateness[k] = m.iif(trucksUsed[k],
m.max(0,
m.sum(m.at(theEnd, m.sub(c, 1)),
m.sub(m.at(m.at(travelTimeWarehouse, m.at(sequence, m.sub(c, 1))),
m.at(timeToMatrixIdx, m.round(m.at(theEnd, m.sub(c, 1))))), maxHorizon))),
0);
// Completing visit after latest_end
HxExpression lateLambda = m
.lambdaFunction(i -> m.max(m.sub(m.at(theEnd, i), m.at(latest, m.at(sequence, i))), 0));
lateness[k] = m.sum(homeLateness[k], m.sum(m.range(0, c), lateLambda));
}
totalLateness = m.sum(lateness);
nbTrucksUsed = m.sum(trucksUsed);
totalDistance = m.div(m.round(m.prod(100, m.sum(distRoutes))), 100);
// Objective: minimize the number of trucks used, then minimize the distance traveled
m.minimize(totalLateness);
m.minimize(nbTrucksUsed);
m.minimize(totalDistance);
m.close();
// Parameterize the optimizer
optimizer.getParam().setTimeLimit(limit);
optimizer.solve();
}
// Write the solution in a file with the following format:
// - number of trucks used and total distance
// - for each truck the customers visited (omitting the start/end at the depot)
private void writeSolution(String fileName) throws IOException {
try (PrintWriter output = new PrintWriter(fileName)) {
output.println(nbTrucksUsed.getValue() + " " + totalDistance.getDoubleValue());
for (int k = 0; k < nbTrucks; ++k) {
if (trucksUsed[k].getValue() != 1)
continue;
// Values in sequence are in 0...nbCustomers. +1 is to put it back in 1...nbCustomers+1
// as in the data files (0 being the depot)
HxCollection customersCollection = customersSequences[k].getCollectionValue();
for (int i = 0; i < customersCollection.count(); ++i) {
output.print((customersCollection.get(i) + 1) + " ");
}
output.println();
}
}
}
// The input files follow the "Solomon" format
private void readInputCvrptw(String fileName) throws IOException {
try (Scanner input = new Scanner(new File(fileName))) {
input.nextLine();
input.nextLine();
input.nextLine();
input.nextLine();
nbTrucks = input.nextInt();
truckCapacity = input.nextInt();
input.nextLine();
input.nextLine();
input.nextLine();
input.nextLine();
input.nextInt();
int depotX = input.nextInt();
int depotY = input.nextInt();
input.nextInt();
input.nextInt();
maxHorizon = input.nextInt();
input.nextInt();
List<Integer> customersX = new ArrayList<Integer>();
List<Integer> customersY = new ArrayList<Integer>();
demandsData = new ArrayList<Integer>();
earliestStartData = new ArrayList<Integer>();
latestEndData = new ArrayList<Integer>();
serviceTimeData = new ArrayList<Integer>();
while (input.hasNextInt()) {
input.nextInt();
int cx = input.nextInt();
int cy = input.nextInt();
int demand = input.nextInt();
int ready = input.nextInt();
int due = input.nextInt();
int service = input.nextInt();
customersX.add(cx);
customersY.add(cy);
demandsData.add(demand);
earliestStartData.add(ready);
latestEndData.add(due + service);// in input files due date is meant as latest start time
serviceTimeData.add(service);
}
nbCustomers = customersX.size();
computeDistanceMatrix(depotX, depotY, customersX, customersY);
}
}
// Computes the distance matrix
private void computeDistanceMatrix(int depotX, int depotY, List<Integer> customersX, List<Integer> customersY) {
distMatrixData = new double[nbCustomers][nbCustomers];
travelTimeData = new double[nbCustomers][nbCustomers][nbTimeIntervals];
timeToMatrixIdxData = new int[maxHorizon];
travelTimeWarehouseData = new double[nbCustomers][nbTimeIntervals];
for (int i = 0; i < nbCustomers; ++i) {
distMatrixData[i][i] = 0;
for (int k = 0; k < nbTimeIntervals; ++k) {
travelTimeData[i][i][k] = 0;
}
for (int j = i + 1; j < nbCustomers; ++j) {
double dist = computeDist(customersX.get(i), customersX.get(j), customersY.get(i), customersY.get(j));
distMatrixData[i][j] = dist;
distMatrixData[j][i] = dist;
int profileIdx = getProfile(dist);
for (int k = 0; k < nbTimeIntervals; ++k) {
double localTravelTime = travelTimeProfileMatrix[profileIdx][k] * dist;
travelTimeData[i][j][k] = localTravelTime;
travelTimeData[j][i][k] = localTravelTime;
}
}
}
for (int i = 0; i < nbTimeIntervals; ++i) {
int timeStepStart = (int) Math.round(timeIntervalSteps[i] * maxHorizon);
int timeStepEnd = (int) Math.round(timeIntervalSteps[i + 1] * maxHorizon);
for (int j = timeStepStart; j < timeStepEnd; ++j) {
timeToMatrixIdxData[j] = i;
}
}
distDepotData = new double[nbCustomers];
for (int i = 0; i < nbCustomers; ++i) {
double dist = computeDist(depotX, customersX.get(i), depotY, customersY.get(i));
distDepotData[i] = dist;
int profileIdx = getProfile(dist);
for (int j = 0; j < nbTimeIntervals; ++j) {
double localTravelTimeWarehouse = travelTimeProfileMatrix[profileIdx][j] * dist;
travelTimeWarehouseData[i][j] = localTravelTimeWarehouse;
}
}
}
private double computeDist(int xi, int xj, int yi, int yj) {
return Math.sqrt(Math.pow(xi - xj, 2) + Math.pow(yi - yj, 2));
}
private int getProfile(double dist) {
int idx = 0;
while (idx < nbDistanceLevels && dist > distanceLevels[idx]) {
idx += 1;
}
return idx;
}
public static void main(String[] args) {
if (args.length < 1) {
System.err.println("Usage: java Tdcvrptw inputFile [outputFile] [timeLimit] [nbTrucks]");
System.exit(1);
}
try (HexalyOptimizer optimizer = new HexalyOptimizer()) {
String instanceFile = args[0];
String outputFile = args.length > 1 ? args[1] : null;
String strTimeLimit = args.length > 2 ? args[2] : "20";
Tdcvrptw model = new Tdcvrptw(optimizer);
model.readInstance(instanceFile);
model.solve(Integer.parseInt(strTimeLimit));
if (outputFile != null) {
model.writeSolution(outputFile);
}
} catch (Exception ex) {
System.err.println(ex);
ex.printStackTrace();
System.exit(1);
}
}
}