def pclone(self, cities, particle, a):
target = self.path[a]
b = particle.maping[target]
# assert b == list(particle.path).index(target)
if abs(a - b) < 2 or abs(a - b) == len(self.path) - 1:
return
src, dst = [a, b], [b, a]
cost_src = cost(cities, self.path, src, src)
cost_dst = cost(cities, self.path, src, dst)
return self.mutate(cities, src, dst, cost_src, cost_dst)
def generate_paretos(self):
already_visited = []
CURRENT = self.evaluator.get_paretos_instances()
PREVIOUS = []
while self.ratio[0] <= 1.0:
print 'Looking for ratios: %s' % (' '.join(map(str, self.ratio)))
PREVIOUS = deepcopy(CURRENT)
cnt = 0
n = len(self.evaluator.get_paretos_instances())
to_copy = random.choice(self.evaluator.get_paretos_instances())
while to_copy in already_visited:
cnt += 1
if cnt > n:
break
to_copy = random.choice(self.evaluator.get_paretos_instances())
already_visited.append(to_copy)
ct = tsp.cost(to_copy, self.objectives)
stop = False
while not stop:
best_neighbor = None
best_cost = float('inf')
# best neighbor
for i in xrange(len(self.instance)):
for j in xrange(i+1, len(self.instance)):
neighbor = deepcopy(to_copy)
neighborhood.swap(neighbor, i, j)
c = tsp.cost(neighbor, self.objectives)
cr = self.proportional_score(c)
if cr < best_cost:
best_neighbor = neighbor
best_cost = cr
if best_cost < self.proportional_score(ct):
to_copy = best_neighbor
ct = tsp.cost(to_copy, self.objectives)
else:
stop = True
self.evaluator.update(to_copy, tuple(ct.values()))
CURRENT = self.evaluator.get_paretos_instances()
with open('results.txt', 'w') as f:
for res in CURRENT:
if res:
f.write(';'.join(map(str, res)))
f.write('\n')
self.update_ratios()
yield self.evaluator.get_paretos_costs()
def mutation(cities, population, a):
pop_m = population[a].copy()
idx = mutate(pop_m, degree=random.randint(2, MUT_DEGREE))
mutation = idx.copy()
np.random.shuffle(mutation)
cost_x = cost(cities, pop_m, idx, idx)
cost_y = cost(cities, pop_m, idx, mutation)
cost_m = fitness[a] - (cost_x - cost_y)
pop_m[idx] = pop_m[mutation]
# cost_w = cost(cities, pop_m, *[range(0, len(pop_m), 2)]*2)
# print(cost_m, cost_w)
# assert cost_m.round() == cost_w.round()
return pop_m, cost_m
def run(self, instance, objectives, budget=100, best=None, plot=False):
self.N = 0
self.budget = budget
self.best = best
self.instance = instance
self.objectives = objectives
c = tsp.cost(self.instance, self.objectives)
self.evaluator.update(self.instance, tuple(c.values()))
if plot:
fig, ax = plt.subplots()
if self.best:
line, = ax.plot([o for o,_ in self.best], [o for _,o in self.best], 'g.')
self.line, = ax.plot([], [], 'r.')
ani = animation.FuncAnimation(fig, self.update, self.generate_paretos)
plt.show()
else:
gen = self.generate_paretos()
try:
while True:
gen.next()
except StopIteration:
pass
return self.evaluator
def generate_paretos(self):
already_visited = []
CURRENT = self.evaluator.get_paretos_instances()
PREVIOUS = []
while self.N < self.budget:
self.N += 1
PREVIOUS = deepcopy(CURRENT)
to_copy = random.choice(self.evaluator.get_paretos_instances())
while to_copy in already_visited:
to_copy = random.choice(self.evaluator.get_paretos_instances())
already_visited.append(to_copy)
for i in xrange(len(self.instance)):
for j in xrange(i+1, len(self.instance)):
neighbor = deepcopy(to_copy)
neighborhood.swap(neighbor, i, j)
c = tsp.cost(neighbor, self.objectives)
self.evaluator.update(neighbor, tuple(c.values()))
self.evaluator.clean_dominated()
CURRENT = self.evaluator.get_paretos_instances()
with open('results.txt', 'w') as f:
for res in CURRENT:
if res:
f.write(';'.join(map(str, res)))
f.write('\n')
yield self.evaluator.get_paretos_costs()
def run(self, instance, objectives, step=0.1, best=None, plot=False):
self.step = step
self.best = best
self.instance = instance
self.objectives = objectives
c = tsp.cost(self.instance, self.objectives)
self.evaluator.update(self.instance, tuple(c.values()))
n = len(objectives)
for i in xrange(n):
self.ratio.append(i / (n - 1.0))
if plot:
fig, ax = plt.subplots()
if self.best:
line, = ax.plot([o for o,_ in self.best], [o for _,o in self.best], 'g.')
self.line, = ax.plot([], [], 'r.')
ani = animation.FuncAnimation(fig, self.update, self.generate_paretos)
plt.show()
else:
gen = self.generate_paretos()
try:
while True:
gen.next()
except StopIteration:
pass
return self.evaluator
def pclone(cities, population, a, b):
for _ in range(len(cities) * 2):
a_i = random.randint(0, len(cities) - 1)
if population[a][a_i] == population[b][a_i]:
continue
pop_c = population[a].copy()
target = pop_c[a_i]
b_i = list(population[b]).index(target)
if abs(a_i - b_i) < 2 or abs(a_i - b_i) == len(pop_c) - 1:
continue
src, dst = [a_i, b_i], [b_i, a_i]
cost_src = cost(cities, pop_c, src, src)
cost_dst = cost(cities, pop_c, src, dst)
cost_c = fitness[a] - (cost_src - cost_dst)
pop_c[src] = pop_c[dst]
return pop_c, cost_c
return None, None
def _backprop(self):
self.particles.sort(key=lambda p: p.error)
# skip outliers
e_min, e_max = self.particles[3].error, self.particles[-4].error
for i, p in enumerate(self.particles):
# velocity like NN momentum
velocity = self._proportional_distance_velocity(
e_min, e_max, p.error, i)
p.error_degree = int(p.optimizer.step(velocity * (e_max - e_min)))
error_degree = 1 + p.error_degree #min(len(p.path)**2, p.error_degree)
leader = random.randint(
0,
0 if i < ELITE else ELITE) #i // 4)#random.randint(0, ELITE)#
for j in range(error_degree):
self.total += 1
# backprop
idx = random.randint(0, len(p.path) - 1)
if self.lrg * velocity > random.random():
if self.particles[0].best.path[idx] != p.path[idx]:
p.pclone(self.cities, self.particles[leader], idx)
idx = random.randint(0, len(p.path) - 1)
if self.lrp * velocity > random.random():
if p.best.path[idx] != p.path[idx]:
p.pclone(self.cities, p.best, idx)
exploration = 2 > random.randint(0, error_degree)
if not exploration:
continue # best we want less to improvize
src = mutate(p.path, degree=2)
dst = [src[1], src[0]]
# noise -> out of local minima
t = self.temperature[p.cooldown()]
cost_src = cost(self.cities, p.path, src, src)
cost_dst = cost(self.cities, p.path, src, dst)
if np.exp((cost_src - cost_dst) / t) > random.random():
p.mutate(self.cities, src, dst, cost_src, cost_dst)
return np.mean([p.error for p in self.particles])
def crossover(cities, population, a, b):
pop_a, pop_b = population[a], population[b]
a, b = sorted(random.sample(range(len(pop_a)), 2))
# a = 0
gene = list(pop_a[a:b])
pop_c = list(filter(lambda g: g not in gene, pop_b))
a = random.randint(0, len(pop_c) - 1)
pop_c = np.array(pop_c[:a] + gene + pop_c[a:]).reshape(-1)
cost_c = cost(cities, pop_c, *[range(0, len(pop_c), 2)] * 2)
return pop_c, cost_c
def __init__(self, cities, optimizer, temperature):
out_size = len(cities)
assert 0 == out_size % 2, "current cost function accepts only odd #cities"
self.optimizer = optimizer
self.path = np.random.choice(np.arange(out_size),
out_size,
replace=False)
self.error = cost(cities, self.path,
*[range(0, len(self.path), 2)] * 2)
self.maping = list(np.argsort(self.path))
self.temp = temperature
self.best = None
self.best = copy.copy(self)
self.error_degree = None
# https://ericphanson.com/blog/2016/the-traveling-salesman-and-10-lines-of-python/
# *also 10 lines of code (w/o comments, empty lines + merge 'if' into one line )
# but with usage of tsp 'library' :) ~ simulated annealing logic is all here.
import random
import numpy as np
from tsp import tsp_map, mutate, cost, plot
cities = tsp_map(n_cities=20, scale=1000)
path = np.random.choice(np.arange(len(cities)), len(cities), replace=False)
# we cut half of logspace as first/second half is bit brutal for temperature
for temperature in reversed(np.logspace(0, 3, 1e5)[:int(1e5 / 2)]):
a, b = mutate(path, degree=2)
# interesting trick: we dont need to checkpoint best path !!
# as if new path better np.exp(-..) is low, best path will survive most likely
if np.exp(
(cost(cities, path, [a, b], [a, b]) -
cost(cities, path, [a, b], [b, a])) / temperature) > random.random():
path[[a, b]] = path[[b, a]]
plot(cities, path)
])
# for idx in trails[:ELITE_POOL, len(visited)]:
# assert diffs[int(mu), int(idx)] == list(neighbours[int(mu)]).index(int(idx))
# heuristic, if 2 possible soutions we dont want to oscilate
sigma.sort()
return sigma[1:len(sigma) // 2 + 1].mean()
scores = []
trails = np.vstack([
np.random.choice(range(len(cities)), size=len(cities), replace=False)
for _ in range(EVAPORATION_POOL + COUNT)
])
total_cost = np.array(
[cost(cities, trail, *[range(0, len(trail), 2)] * 2) for trail in trails])
print("INITIAL SCORE", np.mean(total_cost))
for i in range(200): # * EVAPORATION_POOL // COUNT):
var = 0
for c in range(COUNT):
score = 0
visited = []
stats = []
trail = trails[random.randint(0, ELITE_POOL - 1)] #EVAPORATION_POOL)]#
while len(visited) != len(cities):
mu = trail[len(visited)]
# not actually same as learning rate,
COUNT = 100
MUT_DEGREE = 3 #8#
BOUT_SIZE = 7
TOURNAMENT_COUNT = 10
ELITE = 10
cities = tsp_map(24, 1000)
population = [
np.random.choice(np.arange(len(cities)), len(cities), replace=False)
for _ in range(COUNT)
]
fitness = [
cost(cities, path, *[range(0, len(path), 2)] * 2) for path in population
]
def crossover(cities, population, a, b):
pop_a, pop_b = population[a], population[b]
a, b = sorted(random.sample(range(len(pop_a)), 2))
# a = 0
gene = list(pop_a[a:b])
pop_c = list(filter(lambda g: g not in gene, pop_b))
a = random.randint(0, len(pop_c) - 1)
pop_c = np.array(pop_c[:a] + gene + pop_c[a:]).reshape(-1)
cost_c = cost(cities, pop_c, *[range(0, len(pop_c), 2)] * 2)
return pop_c, cost_c