I am trying to solve a vehicle routing problem with 5 drivers for deliveries. I am using haversine and lat-long to calculate the distance matrix. I am new to OR tools, so following the vrp example.
The issues is that the out 0f 5 drivers, only routes are generated for 2 drivers and these routes are very long. I want to generate multiple shorter routes so that all the drivers are utilized. Can please check if I am setting some constraint wrong.
Can someone please explain, how to set "Distance" dimension and SetGlobalSpanCostCoefficient in google OR-tools. Here is the code and output.
from __future__ import print_functionimport pandas as pdimport numpy as npimport googlemapsimport mathfrom ortools.constraint_solver import routing_enums_pb2from ortools.constraint_solver import pywrapcpgmaps = googlemaps.Client(key='API Key')def calculate_geocodes(): df = pd.read_csv("banglore_zone.csv") df['lat'] = pd.Series(np.repeat(0, df.size), dtype=float) df['long'] = pd.Series(np.repeat(0, df.size), dtype=float) result = np.zeros([df.size, 2]) for index, row in df.iterrows(): # print(row['Address']) geocode_result = gmaps.geocode(row['Address'])[0] lat = (geocode_result['geometry']['location']['lat']) lng = (geocode_result['geometry']['location']['lng']) result[index] = lat, lng df.lat[index] = lat df.long[index] = lng print("First step", df) coords = df.as_matrix(columns=['lat', 'long']) return coords, dfdef calculate_distance_matrix(coordinates, gmaps): distance_matrix = np.zeros( (np.size(coordinates, 0), np.size(coordinates, 0))) # create an empty matrix for distance between all locations for index in range(0, np.size(coordinates, 0)): src = coordinates[index] for ind in range(0, np.size(coordinates, 0)): dst = coordinates[ind] distance_matrix[index, ind] = distance(src[0], src[1], dst[0], dst[1]) return distance_matrixdef distance(lat1, long1, lat2, long2): # Note: The formula used in this function is not exact, as it assumes # the Earth is a perfect sphere. # Mean radius of Earth in miles radius_earth = 3959 # Convert latitude and longitude to # spherical coordinates in radians. degrees_to_radians = math.pi / 180.0 phi1 = lat1 * degrees_to_radians phi2 = lat2 * degrees_to_radians lambda1 = long1 * degrees_to_radians lambda2 = long2 * degrees_to_radians dphi = phi2 - phi1 dlambda = lambda2 - lambda1 a = haversine(dphi) + math.cos(phi1) * math.cos(phi2) * haversine(dlambda) c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a)) d = radius_earth * c return ddef haversine(angle): h = math.sin(angle / 2) ** 2 return hdef create_data_model(distance_matrix, number_of_vehicles, depot):"""Stores the data for the problem.""" data = {} data['distance_matrix'] = distance_matrix print(distance_matrix) data['num_vehicles'] = number_of_vehicles data['depot'] = depot return datadef print_solution(data, manager, routing, solution, address_dataframe):"""Prints solution on console.""" max_route_distance = 0 for vehicle_id in range(data['num_vehicles']): index = routing.Start(vehicle_id) plan_output = 'Route for vehicle {}:\n'.format(vehicle_id) route_distance = 0 while not routing.IsEnd(index): plan_output += ' {} ---> '.format(address_dataframe.iloc[manager.IndexToNode(index), 0]) previous_index = index index = solution.Value(routing.NextVar(index)) route_distance += routing.GetArcCostForVehicle( previous_index, index, vehicle_id) plan_output += '{}\n'.format(manager.IndexToNode(index)) plan_output += 'Distance of the route: {}m\n'.format(route_distance) print(plan_output) max_route_distance = max(route_distance, max_route_distance) print('Maximum of the route distances: {}m'.format(max_route_distance))def main(): coordinates, address_dataframe = calculate_geocodes() distance_matrix = calculate_distance_matrix(coordinates, gmaps) data = create_data_model(distance_matrix, 5, 0) # Create the routing index manager. manager = pywrapcp.RoutingIndexManager( len(data['distance_matrix']), data['num_vehicles'], data['depot']) # Create Routing Model. routing = pywrapcp.RoutingModel(manager) # Create and register a transit callback. def distance_callback(from_index, to_index):"""Returns the distance between the two nodes.""" # Convert from routing variable Index to distance matrix NodeIndex. from_node = manager.IndexToNode(from_index) to_node = manager.IndexToNode(to_index) return data['distance_matrix'][from_node][to_node] transit_callback_index = routing.RegisterTransitCallback(distance_callback) # Define cost of each arc. routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index) # Add Distance constraint. dimension_name = 'Distance' routing.AddDimension( transit_callback_index, 0, # no slack 80, # vehicle maximum travel distance True, # start cumul to zero dimension_name) distance_dimension = routing.GetDimensionOrDie(dimension_name) distance_dimension.SetGlobalSpanCostCoefficient(100) # Setting first solution heuristic. search_parameters = pywrapcp.DefaultRoutingSearchParameters() search_parameters.local_search_metaheuristic = ( routing_enums_pb2.LocalSearchMetaheuristic.GUIDED_LOCAL_SEARCH) search_parameters.time_limit.seconds = 120 search_parameters.log_search = False # Solve the problem. solution = routing.SolveWithParameters(search_parameters) # Print solution on console. if solution: print_solution(data, manager, routing, solution, address_dataframe)if __name__ == '__main__': main()And the distance matrix and output is -
> [[ 0. 0.31543319 3.36774402 ... 8.79765925 8.94261055> 8.83759758] [ 0.31543319 0. 3.09418962 ... 8.81074289 8.95034082> 8.84901702] [ 3.36774402 3.09418962 0. ... 10.87348059 10.97329493> 10.89962072] ... [ 8.79765925 8.81074289 10.87348059 ... 0. 0.20726879> 0.06082994] [ 8.94261055 8.95034082 10.97329493 ... 0.20726879 0.> 0.1465572 ] [ 8.83759758 8.84901702 10.89962072 ... 0.06082994 0.1465572> 0. ]] Route for vehicle 0: 3Embed software 10th Cross St, RBI Colony, Ganganagar, Bengaluru, Karnataka 560024 ---> 0 Distance of> the route: 0m> > Route for vehicle 1: 3Embed software 10th Cross St, RBI Colony,> Ganganagar, Bengaluru, Karnataka 560024 ---> 0 Distance of the route:> 0m> > Route for vehicle 2: 3Embed software 10th Cross St, RBI Colony,> Ganganagar, Bengaluru, Karnataka 560024 ---> Sindhi High School,> Kempapura ---> Hoppers stop Building No.12, Krishnaja Avenue, Near> Kogilu Cross, International Airport Road, Yelahanka, Bengaluru ---> > Kempegowda International Airport Bengaluru ---> mvit International> Airport Road, Hunasamaranahalli, Yelahanka, Krishnadeveraya Nagar,> Bengaluru ---> Canadian International School 4 & 20, Manchenahalli,> Yelahanka, Bengaluru ---> brick factory RMZ Galleria, Office Block,> Ground Floor, B.B. Road, Yelahanka ---> Jakkur Aerodrome Bellary> Road, Post, Yelahanka, Bengaluru, Karnataka ---> Godrej Platinum> International Airport Road, Hebbal, Bengaluru, Karnataka ---> Vidya> Niketan School 30, Kempapura Main Road, Kempapura, Hebbal, Bengaluru,> Karnataka ---> Atria Institute of Technology, 1st Main Rd, Ags> Colony, Anandnagar, Hebbal, Bengaluru, Karnataka ---> 0 Distance of> the route: 26m> > Route for vehicle 3: 3Embed software 10th Cross St, RBI Colony,> Ganganagar, Bengaluru, Karnataka 560024 ---> Caffe cofee day CBI road> banglore ---> 0 Distance of the route: 0m> > Route for vehicle 4: 3Embed software 10th Cross St, RBI Colony,> Ganganagar, Bengaluru, Karnataka 560024 ---> RT Nagar Police station> ---> bus stop mekhri circle banglore ---> Truffles 80 Feet Road, Jaladarsini Layout, Sanjaynagar Banglore ---> BEL circle banglore> ---> Paragon Outlet Shivapura, Peenya, Bengaluru ---> Taj vivanta Yeshwantpur, Bengaluru ---> Orion Mall A Block, Brigade Gateway, Dr> Rajkumar Rd, Malleshwaram, Bengaluru ---> brand factory Malleshwaram> Banglore ---> Mantri Square Mall, Sampige Road, Malleshwaram,> Bengaluru, Karnataka ---> Krantivira Sangolli Rayanna Bengaluru, M.G.> Railway Colony, Majestic, Bengaluru ---> UB city banglore ---> > Brigade road banglore ---> MG Road metro station Banglore ---> > commercial street bangalore ---> Infantry Road, Beside Prestige> Building, Tasker Town, Shivaji Nagar, Bengaluru, Karnataka ---> > Garuda Mall Magrath Rd, Ashok Nagar, Bengaluru ---> Brand Factory -> Home Town Above HomeTown, Vanshee Towers, Survey No.92/4 3rd and 4th> Floors, Outer Ring Rd, Marathahalli, Bengaluru ---> KLM Shopping> Mall, Marathahalli Bridge Marathahalli ---> Favourite Shop HAL Old> Airport Rd, Subbaiah Reddy Colony, Marathahalli Village, Marathahalli,> Bengaluru ---> Max RPR Plaza, Varthur Rd, Marathahalli, Bengaluru> ---> Pick 'n' Move Shop No. 102, Ground Floor, Varthur Rd, Marathahalli Village, Marathahalli, Bengaluru ---> Lotto Shoes 45/2,> Varthur Rd, Marathahalli Village, Marathahalli, Bengaluru, Karnataka > ---> The Raymond Shop Opp. Mga Hospital, Marathalli Main Road Near Ring Road Junction, Bengaluru, Karnataka ---> chinnaswamy stadium> banglore ---> fun cinemas cunningham road Banglore ---> Cant station> banglore ---> Radhakrishna Theatre 25, 1st Main Rd, Mattdahally, RT> Nagar, Bengaluru ---> Presidency School Near R T Nagar, HMT Layout,> Bengaluru, Karnataka ---> 0 Distance of the route: 20m> > Maximum of the route distances: 26m
