def Two_Opt_solver(self, G_prime, G_prime_nodes, start_index,
cluster_center_drop_off):
tsp = TSP()
tsp.read_mat(nx.adjacency_matrix(G_prime).todense())
two_opt = TwoOpt_solver(initial_tour='NN', iter_num=100)
best_tour = tsp.get_approx_solution(two_opt)
center_tour = [G_prime_nodes[node] for node in best_tour]
if (center_tour.count(start_index) == 1):
start_loc = center_tour.index(start_index)
center_tour = center_tour[start_loc:] + center_tour[:start_loc] + [
start_index
]
tour = [(center_tour[i], center_tour[i + 1])
for i in range(len(center_tour) - 1)]
rao_tour_1 = compute_tour_paths(self.G, tour)
rao_tour_1 = [
rao_tour_1[i] for i in range(len(rao_tour_1) - 1)
if rao_tour_1[i] != rao_tour_1[i + 1]
] + [start_index]
cost_1 = self.faster_cost_solution(rao_tour_1, cluster_center_drop_off)
return rao_tour_1, cost_1
def make_path(X, D):
tsp = TSP()
# Using the data matrix
tsp.read_data(X)
# Using the distance matrix
tsp.read_mat(D)
from tspy.solvers import TwoOpt_solver
two_opt = TwoOpt_solver(initial_tour='NN', iter_num=10000)
two_opt_tour = tsp.get_approx_solution(two_opt)
#tsp.plot_solution('TwoOpt_solver')
best_tour = tsp.get_best_solution()
return best_tour
def solve(self):
self.FloydWarshall()
tsp = TSP()
tsp.read_mat(np.array(self.dist, dtype=np.float64))
two_opt = TwoOpt_solver(initial_tour='NN', iter_num=1000000)
tsp.get_approx_solution(two_opt)
path = tsp.get_best_solution()
path = path[1:] # Trim the start vertex
start_idx = path.index(self.start)
# Make sure the path starts and ends at Soda
path = path[start_idx:] + path[:start_idx] + [self.start]
changed = True
# Not the most efficient, but oh well
while changed:
changed = False
for i in range(len(path) - 1):
u, v = path[i], path[i + 1]
if self.adj[u][v] == Solver.INF:
# This isn't an edge in the graph, so splice in the shortest path
path[i:i + 2] = self.path[u][v]
changed = True
break
# check all cycles along path to see if compression is better
path = self.compressCycles(path)
# try to remove dropoff locations
path = self.removeDropoffLocations(path)
# try to compress dropoff pairs
path = self.compressDropoffPairs(path)
self.finalPath = path
# calculate final energy
_, totalDist = self.calcDropoffsAndDist(path)
return totalDist
from tspy import TSP
import matplotlib.pyplot as plt
from tspy.solvers import TwoOpt_solver
from tspy.lower_bounds import Held_Karp
from tspy.lower_bounds import Connected_LP_bound
import numpy as np
a = TSP()
N = 100
a.read_data(np.random.rand(N, 2))
sol = TwoOpt_solver('NN')
a.get_approx_solution(sol)
plt.figure(figsize=(5, 5))
a.plot_solution('TwoOpt_solver')
a.get_lower_bound(Connected_LP_bound())
a.get_lower_bound(
Held_Karp(n_iter=1000, batch_size=50, alp_factor=1, start_alp=0.001))
from tspy import TSP
from tspy.lower_bounds import Simple_LP_bound
from tspy.lower_bounds import Connected_LP_bound
from tspy.lower_bounds import MinCut_LP_bound
from tspy.solvers import TwoOpt_solver
from tspy.solvers import NN_solver
import numpy as np
a = TSP()
N = 20
print(N)
a.read_data(np.random.rand(N, 2))
a.get_approx_solution(TwoOpt_solver('NN'))
a.get_approx_solution(NN_solver())
bounds = [Simple_LP_bound(), Connected_LP_bound(), MinCut_LP_bound()]
for b in bounds:
a.get_lower_bound(b)
print(a.lower_bounds)
a.get_best_solution()
a.get_best_lower_bound()
graph['fake'][start_node] = 1
for node in graph.keys():
if node in ['fake', start_node]:
continue
graph[node]['fake'] = 1
# Create distance matrix:
M = np.ndarray(shape=(N, N), dtype=float)
for i, adr in enumerate(addresses):
for j, adr2 in enumerate(addresses):
if i == j:
M[i, j] = np.inf
else:
M[i, j] = graph[adr][adr2]
tsp = TSP()
tsp.read_mat(M)
print("Solving using 2-opt heuristic for TSP:")
two_opt = TwoOpt_solver(initial_tour='NN', iter_num=100)
two_opt_tour = tsp.get_approx_solution(two_opt)
for idx in range(len(two_opt_tour) - 1):
a = addresses[two_opt_tour[idx]]
b = addresses[two_opt_tour[idx + 1]]
print(f'From: {a}')
print(f'To..: {b}')
print('Time: {} min'.format(graph[a][b]))
print('')
from tspy import TSP
from tspy.solvers import NN_solver
from tspy.solvers import TwoOpt_solver
import numpy as np
a = TSP()
N = 150
a.read_data(np.random.rand(N, 2))
sol = NN_solver()
a.get_approx_solution(sol)
a.plot_solution('NN_solver')
sol = TwoOpt_solver(list(a.tours.values())[0], 500)
a.get_approx_solution(sol)
a.plot_solution('TwoOpt_solver')