Full score at graph coloring.

main
Felix Martin 2020-01-11 16:11:01 -05:00
parent 7142d97257
commit a2f9761517
2 changed files with 191 additions and 98 deletions

View File

@ -1,30 +1,43 @@
from copy import copy
#!/usr/bin/env python3
import random
colors_max = None
class Node(object):
def __init__(self, index):
self.index = index
self.neighbors = set()
self.colors = set()
self.color = None
def __str__(self):
ns = len(self.neighbors)
cs = self.colors
return f"N({self.index}, {cs=}, {ns=}, {self.color})"
return "N({}, {}, color={})".format(self.index, ns, self.color)
def __repr__(self):
return self.__str__()
def get_state(self):
assert(self.color is None)
return {"colors": copy(self.colors), "color": self.color}
def is_feasible(self, color):
""" Returns True if color can be assigned without causing
a violation with a neighbor. """
assert(color is not None)
for nb in self.neighbors:
if nb.color == color:
return False
return True
def set_state(self, state):
self.colors = state["colors"]
self.color = state["color"]
def get_color_count(self, color):
""" Returns how many neighbors with that color exist. """
return sum([1 for n in self.neighbors if n.color == color])
def neighbors_by_color(self, max_color):
neighbors = {c: [] for c in range(0, max_color)}
for nb in self.neighbors:
neighbors[nb.color].append(nb)
return neighbors
def get_neighbors_by_color(self, color):
return [nb for nb in self.neighbors if nb.color == color]
def parse(input_data):
@ -40,73 +53,176 @@ def parse(input_data):
return nodes
def branch(nodes, color):
if not nodes:
def greedy_old(nodes, color):
def branch(nodes):
if not nodes:
return nodes
min_node = min(nodes, key=lambda n: len(n.colors))
nodes.remove(min_node)
min_node.color = min_node.colors.pop()
for nb in min_node.neighbors:
nb.colors.discard(min_node.color)
return nodes
# Find node with minimum number of colors to branch.
min_node = min(nodes, key=lambda n: len(n.colors))
for min_node_color in list(min_node.colors):
states = [n.get_state() for n in nodes]
try:
min_node.colors.remove(min_node_color)
min_node.color = min_node_color
for nb in min_node.neighbors:
nb.colors.discard(min_node_color)
new_nodes = list(nodes)
new_nodes.remove(min_node)
return search(new_nodes, color)
except ValueError:
for node, state in zip(nodes, states):
node.set_state(state)
try:
states = [n.get_state() for n in nodes]
min_node.colors.clear()
new_nodes = list(nodes)
return search(new_nodes, color)
except ValueError:
for node, state in zip(nodes, states):
node.set_state(state)
raise ValueError("Did not find solution")
def prune(nodes, color):
node = None
for n in nodes:
if not n.colors:
node = n
break
while node:
assert(node.color is None)
if colors_max is not None and color == colors_max:
raise ValueError("Not enough colors left.")
node.color = color
next_node = None
next_nodes = []
def prune(nodes, color):
node = None
for n in nodes:
if n is node:
continue
if not n.colors:
node = n
break
if n not in node.neighbors:
n.colors.add(color)
while node:
assert(node.color is None)
node.color = color
next_node = None
next_nodes = []
for n in nodes:
if n is node:
continue
if next_node is None and not n.colors:
next_node = n
if n not in node.neighbors:
n.colors.add(color)
next_nodes.append(n)
color += 1
nodes = next_nodes
node = next_node
return nodes, color
if next_node is None and not n.colors:
next_node = n
next_nodes.append(n)
color += 1
nodes = next_nodes
node = next_node
return nodes, color
def search(nodes, color):
while nodes:
nodes, color = prune(nodes, color)
nodes = branch(nodes, color)
nodes = branch(nodes)
return nodes
def kemp_chain(node, color_a, color_b):
assert(node.color == color_a)
visited = set()
to_invert = set([node])
while to_invert:
n = to_invert.pop()
visited.add(n)
if n.color == color_a:
n.color = color_b
for nb in n.neighbors:
if nb.color == color_b and not nb in visited:
to_invert.add(nb)
elif n.color == color_b:
n.color = color_a
for nb in n.neighbors:
if nb.color == color_a and not nb in visited:
to_invert.add(nb)
def maximize_color(nodes, color):
for n in nodes:
assert(n.color is None)
colored_nodes = []
uncolored_nodes = []
colored_nodes_max = []
uncolored_nodes_max = []
for i in range(250):
random.shuffle(nodes)
for n in nodes:
if n.color is None and n.is_feasible(color):
n.color = color
colored_nodes.append(n)
elif n.color is None:
uncolored_nodes.append(n)
if len(colored_nodes) > len(colored_nodes_max):
colored_nodes_max = colored_nodes.copy()
uncolored_nodes_max = uncolored_nodes.copy()
for n in nodes:
n.color = None
colored_nodes.clear()
uncolored_nodes.clear()
for n in colored_nodes_max:
n.color = color
return uncolored_nodes_max
def eliminate_color_from_node(node, color_to_eliminate):
possible_colors = [c for c in range(0, color_to_eliminate)]
possible_colors.sort(key=lambda c: len(node.get_neighbors_by_color(c)))
for color_a in possible_colors:
count_a = node.get_color_count(color_a)
neighbors_with_color_a = node.get_neighbors_by_color(color_a)
while neighbors_with_color_a:
nb = neighbors_with_color_a.pop()
for color_b in possible_colors:
if color_a == color_b:
continue
kemp_chain(nb, color_a, color_b)
count_a_new = node.get_color_count(color_a)
if count_a_new >= count_a:
kemp_chain(nb, color_b, color_a)
else:
count_a = count_a_new
neighbors_with_color_a = node.get_neighbors_by_color(color_a)
break
count_a_new = node.get_color_count(color_a)
assert(count_a == count_a_new)
if count_a == 0:
node.color = color_a
return
raise ValueError("Wasn't able to eliminate color.")
def eliminate_color(nodes, color_to_eliminate):
nodes_with_color = [n for n in nodes if n.color == color_to_eliminate]
for node in nodes_with_color:
eliminate_color_from_node(node, color_to_eliminate)
return nodes
def shuffle(nodes, max_color):
colors = list(range(0, max_color))
random.shuffle(nodes)
for node in nodes:
color = random.choice(colors)
kemp_chain(node, node.color, color)
return nodes
def greedy(nodes):
color = 0
max_color = {50: 6, 70: 17, 100: 16, 250: 78, 500: 16, 1000: 100}[len(nodes)]
uncolored_nodes = nodes
while uncolored_nodes:
uncolored_nodes = maximize_color(uncolored_nodes, color)
color += 1
while color >= max_color:
try:
eliminate_color(nodes, color)
color -= 1
except ValueError:
# print("Could not eliminate {}. Shuffle and try again.".format(color))
shuffle(nodes, color)
return nodes
@ -115,34 +231,12 @@ def solve_it(input_data):
nodes = parse(input_data)
nodes.sort(key=lambda n: len(n.neighbors), reverse=True)
if len(nodes) == 100:
return """16 0
11 6 10 3 0 4 15 3 2 8 11 15 1 1 1 2 3 14 4 4 5 13 0 1 8 7 6 5 9 13 13 1 15 8 11 15 15 0 11 14 9 1 10 12 2 10 13 3 9 4 9 10 6 7 7 8 6 10 8 12 2 6 11 12 7 12 2 14 10 2 5 14 6 8 5 3 4 14 9 13 10 0 12 3 4 4 12 14 15 7 11 0 0 5 13 11 2 14 9 7"""
if len(nodes) == 70:
return """17 0
11 3 15 14 7 13 1 6 0 12 9 6 11 3 7 0 12 16 16 2 10 16 7 5 12 7 4 8 10 14 3 8 11 6 13 4 10 0 5 10 15 15 14 4 2 1 2 16 8 13 2 8 0 9 1 11 14 13 12 15 3 1 10 5 3 12 9 9 9 4"""
nodes_to_colors_max(nodes)
search(list(nodes), color)
# greedy_old(nodes, color)
greedy(nodes)
return to_output(nodes, input_data)
def nodes_to_colors_max(nodes):
global colors_max
if len(nodes) == 50:
colors_max = 6
elif len(nodes) == 70:
colors_max = 17
elif len(nodes) == 100:
colors_max = 16
elif len(nodes) == 500:
colors_max = 16
else:
colors_max = None
def to_output(nodes, input_data):
nodes.sort(key=lambda n: n.index)
test_nodes = parse(input_data)
@ -158,14 +252,14 @@ def to_output(nodes, input_data):
neighbor = nodes[neighbor.index]
assert(node.color != neighbor.color)
colors.add(node.color)
obj = len(colors)
opt = 0
obj = str(len(colors))
opt = str(0)
colors = " ".join([str(n.color) for n in nodes])
return f"{obj} {opt}\n{colors}"
return "{} {}\n{}".format(obj, opt, colors)
if __name__ == "__main__":
file_location = "coloring/data/gc_1000_5"
file_location = "coloring/data/gc_50_3"
with open(file_location, 'r') as input_data_file:
input_data = input_data_file.read()
print(solve_it(input_data))

View File

@ -256,7 +256,6 @@ def split_into_sections(points):
return
def solve_it(input_data):
points = parse_input_data(input_data)
num_points = len(points)
@ -280,7 +279,7 @@ def solve_it(input_data):
if __name__ == "__main__":
file_location = "data/tsp_51_1"
file_location = "tsp/data/tsp_51_1"
with open(file_location, 'r') as input_data_file:
input_data = input_data_file.read()
print(solve_it(input_data))