discrete_optimization/facility/solver.py

77 lines
2.6 KiB
Python
Executable File

#!/usr/bin/python
# -*- coding: utf-8 -*-
from collections import namedtuple
from facility import solve_it
import math
Point = namedtuple("Point", ['x', 'y'])
Facility = namedtuple("Facility", ['index', 'setup_cost', 'capacity', 'location'])
Customer = namedtuple("Customer", ['index', 'demand', 'location'])
def length(point1, point2):
return math.sqrt((point1.x - point2.x)**2 + (point1.y - point2.y)**2)
def solve_it_example(input_data):
# Modify this code to run your optimization algorithm
# parse the input
lines = input_data.split('\n')
parts = lines[0].split()
facility_count = int(parts[0])
customer_count = int(parts[1])
facilities = []
for i in range(1, facility_count+1):
parts = lines[i].split()
facilities.append(Facility(i-1, float(parts[0]), int(parts[1]), Point(float(parts[2]), float(parts[3])) ))
customers = []
for i in range(facility_count+1, facility_count+1+customer_count):
parts = lines[i].split()
customers.append(Customer(i-1-facility_count, int(parts[0]), Point(float(parts[1]), float(parts[2]))))
# build a trivial solution
# pack the facilities one by one until all the customers are served
solution = [-1]*len(customers)
capacity_remaining = [f.capacity for f in facilities]
facility_index = 0
for customer in customers:
if capacity_remaining[facility_index] >= customer.demand:
solution[customer.index] = facility_index
capacity_remaining[facility_index] -= customer.demand
else:
facility_index += 1
assert capacity_remaining[facility_index] >= customer.demand
solution[customer.index] = facility_index
capacity_remaining[facility_index] -= customer.demand
used = [0]*len(facilities)
for facility_index in solution:
used[facility_index] = 1
# calculate the cost of the solution
obj = sum([f.setup_cost*used[f.index] for f in facilities])
for customer in customers:
obj += length(customer.location, facilities[solution[customer.index]].location)
# prepare the solution in the specified output format
output_data = '%.2f' % obj + ' ' + str(0) + '\n'
output_data += ' '.join(map(str, solution))
return output_data
if __name__ == '__main__':
import sys
if len(sys.argv) > 1:
file_location = sys.argv[1].strip()
with open(file_location, 'r') as input_data_file:
input_data = input_data_file.read()
print(solve_it(input_data))
else:
print('This test requires an input file. Please select one from the data directory. (i.e. python solver.py ./data/fl_16_2)')