def test_random(self, _, seed):
'Test method = "random" for a range of seeds'
alg = BiDirectional(self.G, self.max_res, self.min_res, seed=seed)
# Run and test results
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertTrue(all(alg.consumed_resources == self.consumed_resources))
def test_backward(self):
alg = BiDirectional(self.G,
self.max_res,
self.min_res,
direction='backward')
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertTrue(alg.consumed_resources == self.consumed_resources)
def test_bidirectional(self):
"""
Test BiDirectional with randomly chosen sequence of directions
for a range of seeds.
"""
alg = BiDirectional(self.G, self.max_res, self.min_res)
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertEqual(alg.consumed_resources, self.consumed_resources)
def test_unprocessed(self):
'Test method = "unprocessed"'
alg = BiDirectional(self.G,
self.max_res,
self.min_res,
method="unprocessed")
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertTrue(alg.consumed_resources == self.consumed_resources)
def test_bidirectional_forward(self):
"""Test BiDirectional with custom callback."""
alg = BiDirectional(self.G,
self.max_res,
self.min_res,
direction="forward",
REF_callback=self.my_callback)
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertEqual(alg.consumed_resources, self.consumed_resources)
def test_bidirectional(self):
"""Test BiDirectional with custom callback."""
alg = BiDirectional(self.G,
self.max_res,
self.min_res,
method="unprocessed",
REF_callback=self.my_callback)
# Overwrite graph as original labelling won't match
self.my_callback.G = alg.G
alg.run()
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertEqual(alg.consumed_resources, self.consumed_resources)
def test_unprocessed_time_limit(self):
'Test time_limit parameter'
alg = BiDirectional(self.G,
self.max_res,
self.min_res,
method="unprocessed",
time_limit=0.001)
start = time()
alg.run()
self.assertTrue(time() - start <= 0.001 + 1e-3)
self.assertEqual(alg.path, self.result_path)
self.assertEqual(alg.total_cost, self.total_cost)
self.assertTrue(alg.consumed_resources == self.consumed_resources)
def solve(self, time_limit):
"""
Solves the subproblem with cspy.
Time limit is reduced by 0.5 seconds as a safety window.
Resolves at most twice:
1. using elementary = False,
2. using elementary = True, and threshold, if a route has already been
found previously.
"""
if not self.run_subsolve:
return self.routes, False
self.formulate()
logger.debug("resources = {}".format(self.resources))
logger.debug("min res = {}".format(self.min_res))
logger.debug("max res = {}".format(self.max_res))
more_routes = False
my_callback = self.get_REF()
direction = ("forward" if
(self.time_windows or self.pickup_delivery
or self.distribution_collection) else "both")
# Run only twice: Once with `elementary=False` check if route already
# exists.
s = ([False, True] if (not self.distribution_collection
and not self.elementary) else [True])
for elementary in s:
if elementary:
# Use threshold if non-elementary (safe-guard against large
# instances)
thr = self._avg_path_len * min(self.G.edges[i, j]["weight"]
for (i, j) in self.G.edges())
else:
thr = None
logger.debug(
f"Solving subproblem using elementary={elementary}, threshold={thr}, direction={direction}"
)
alg = BiDirectional(
self.sub_G,
self.max_res,
self.min_res,
threshold=thr,
direction=direction,
time_limit=time_limit - 0.5 if time_limit else None,
elementary=elementary,
REF_callback=my_callback,
# pickup_delivery_pairs=self.pickup_delivery_pairs,
)
# Pass processed graph
if my_callback is not None:
my_callback._sub_G = alg.G
my_callback._source_id = alg._source_id
my_callback._sink_id = alg._sink_id
alg.run()
logger.debug("subproblem")
logger.debug("cost = %s", alg.total_cost)
logger.debug("resources = %s", alg.consumed_resources)
if alg.total_cost is not None and alg.total_cost < -(1e-3):
new_route = self.create_new_route(alg.path)
logger.debug(alg.path)
path_len = len(alg.path)
if not any(
list(new_route.edges()) == list(r.edges())
for r in self.routes):
more_routes = True
self.routes.append(new_route)
self.total_cost = new_route.graph["cost"]
logger.debug("reduced cost = %s", alg.total_cost)
logger.debug("real cost = %s", self.total_cost)
if path_len > 2:
self._avg_path_len += (
path_len - self._avg_path_len) / self._iters
self._iters += 1
break
else:
logger.info("Route already found, finding elementary one")
else:
break
return self.routes, more_routes
def solve(self, time_limit):
"""
Solves the subproblem with cspy.
Resolves until:
1. heuristic algorithm gives a new route (column with -ve reduced cost);
2. exact algorithm gives a new route;
3. neither heuristic nor exact give a new route.
Note : time_limit has no effect for the moment
"""
if not self.run_subsolve:
return self.routes, False
self.formulate()
logger.debug("resources = {}".format(self.resources))
logger.debug("min res = {}".format(self.min_res))
logger.debug("max res = {}".format(self.max_res))
more_routes = False
while True:
if self.exact:
logger.debug("solving with bidirectional")
self.alg = BiDirectional(
self.sub_G,
self.max_res,
self.min_res,
direction="both",
method="generated",
REF_forward=self.get_REF("forward"),
REF_backward=self.get_REF("backward"),
REF_join=self.get_REF("join"),
)
else:
logger.debug("solving with greedyelim")
self.alg = GreedyElim(
self.sub_G,
self.max_res,
self.min_res,
REF=self.get_REF("forward"),
max_depth=40,
)
self.alg.run()
logger.debug("subproblem")
logger.debug("cost = %s" % self.alg.total_cost)
logger.debug("resources = %s" % self.alg.consumed_resources)
if self.alg.total_cost < -(10**-3):
more_routes = True
self.add_new_route()
logger.debug("new route %s" % self.alg.path)
logger.debug("reduced cost = %s" % self.alg.total_cost)
logger.debug("real cost = %s" % self.total_cost)
break
# If not already solved exactly
elif not self.exact:
# Solve exactly from here on
self.exact = True
# Solved heuristically and exactly and no more routes
else:
break
return self.routes, more_routes
def test_time_limit_raises(self):
'Time limit of 0 raises an exception'
alg = BiDirectional(self.G, self.max_res, self.min_res, time_limit=0)
alg.run()
with self.assertRaises(Exception) as context:
alg.path
