def test_random_graph_2():
nodes = 10000
links = 1
err1 = err2 = ""
try:
g = random_xy_graph(nodes=nodes,
edges=links,
x_max=80,
y_max=40,
seed=42)
except ValueError as e:
err1 = str(e)
pass
nodes = 10
links = (sum(range(nodes)) * 2) + 1
try:
g = random_xy_graph(nodes=nodes,
edges=links,
x_max=800,
y_max=400,
seed=42)
except ValueError as e:
err2 = str(e)
pass
assert str(err1) != str(err2)
links = 1
g = random_xy_graph(nodes=nodes, edges=links, x_max=7, y_max=2, seed=42)
# the xy_space above is so small that the generator must switch from random
# mode, to search mode.
links = nodes * nodes # this is a fully connected graph.
g = random_xy_graph(nodes=nodes,
edges=links,
x_max=800,
y_max=400,
seed=42)
# edges=None creates a fully connected graph
g2 = random_xy_graph(nodes=nodes,
edges=None,
x_max=800,
y_max=400,
seed=42)
assert len(g.nodes()) == len(g2.nodes())
assert len(g.edges()) == len(g2.edges())
def graph07():
nodes = 10
links = 30
g = random_xy_graph(nodes=nodes,
edges=links,
x_max=800,
y_max=400,
seed=42)
assert isinstance(g, Graph)
assert len(g.nodes()) == nodes
assert len(g.edges()) == links
return g
def test_random_graph_3_bnb():
from random import seed, randint
for i in range(4, 12):
s = randint(1, 1e7)
seed(s)
g = random_xy_graph(i, x_max=800,
y_max=400) # a fully connected graph.
g = simplify(g)
d1, t1 = g.solve_tsp('bnb')
d2, t2 = g.solve_tsp('greedy')
assert d1 <= d2 or math.isclose(d1, d2), (d1, d2, g.edges())
print(i, s, "|", round(100 * ((d2 - d1) / d1)),
"% greedy dist excess rel to bnb dist")
def test_random_graph_3():
g = random_xy_graph(200, x_max=800, y_max=400) # a fully connected graph.
dist, tour = tsp_greedy(g)
# convert the route to a graph.
g = Graph()
a = tour[0]
for b in tour[1:]:
g.add_edge(a, b, xy_distance(a, b))
a = b
# add the link back to start.
b = tour[0]
g.add_edge(a, b, xy_distance(a, b))
# add a red diamond for the starting point.
if not visuals_enabled:
return
plt = plot_2d(g)
start = tour[0:1]
xs, ys = [c[0] for c in start], [c[1] for c in start]
plt.plot(xs, ys, 'rD', clip_on=False)
plt.show()
def test_random_graph_3():
g = random_xy_graph(200, x_max=800, y_max=400) # a fully connected graph.
dist, tour = tsp(g)
# convert the route to a graph.
g = Graph()
a = tour[0]
for b in tour[1:]:
g.add_edge(a, b, xy_distance(a, b))
a = b
# add the link back to start.
b = tour[0]
g.add_edge(a, b, xy_distance(a, b))
# add a red diamond for the starting point.
try:
plt = plot_2d(g)
start = tour[0:1]
xs, ys = [c[0] for c in start], [c[1] for c in start]
plt.plot(xs, ys, 'rD', clip_on=False)
plt.show()
except (ValueError, ImportError):
pass
def test_random_graph_4():
""" check that the string method is correct. """
g = random_xy_graph(1000, 1000, 1000, 7000)
assert len(g.edges()) == 7000
s = str(g)
assert s == 'Graph(1000 nodes, 7000 edges)', s