def generate_routes(schools,
permutation=None,
partial_route_plan=None,
sped=False):
all_stops = []
for school in schools:
all_stops.extend(school.unrouted_stops)
#Initialize stop values
for stop in all_stops:
stop.update_value(None)
#We will process the stops in order of distance
#from their schools
#The second and part of the tuple improves
#determinism of the sorting algorithm.
all_stops = sorted(all_stops,
key=lambda s:
(-trav_time(s, s.school), s.school.school_name))
if len(all_stops) == 0:
return []
if permutation != None:
all_stops = [all_stops[i] for i in permutation]
routes = []
near_schools = determine_school_proximities(schools)
if partial_route_plan != None:
apply_partial_route_plan(partial_route_plan, all_stops, routes)
while len(all_stops) > 0:
current_route = Route()
#Pick up the most distant stop
init_stop = all_stops[0]
root_school = init_stop.school
root_school.unrouted_stops.remove(init_stop)
all_stops.remove(init_stop)
#Figure out which schools can be mixed with the stop
admissible_schools = near_schools[root_school]
if sped: #special ed: no mixed load routing
admissible_schools = set([root_school])
current_route.add_stop(init_stop)
e_no_h = False
h_no_e = False
if init_stop.e > 0 and init_stop.h == 0:
e_no_h = True
if init_stop.h > 0 and init_stop.e == 0:
h_no_e = True
#Now we will try to add a stop
while True:
oldlength = current_route.length
current_route.backup("generation")
#best_score = -100000
best_score = constants.EVALUATION_CUTOFF
best_stop = None
for school in admissible_schools:
for stop in school.unrouted_stops:
#Not feasibile with respect to age types
if (e_no_h and stop.h > 0 and stop.e == 0
or h_no_e and stop.e > 0 and stop.h == 0):
continue
if current_route.insert_mincost(stop):
#Stop was successfully inserted.
#Determine the score of the stop
#We want to penalize large time
#increases while rewarding collecting
#faraway stops.
time_cost = current_route.length - oldlength
value = stop.value
score = value - time_cost
#stop in the same place, but different age
if time_cost == 0:
score = 100000
if score > best_score:
best_score = score
best_stop = stop
current_route.restore("generation")
if best_stop == None:
break
msg = "Failed to insert stop after insertion was verified"
assert current_route.insert_mincost(best_stop), msg
best_stop.school.unrouted_stops.remove(best_stop)
all_stops.remove(best_stop)
for stop in best_stop.school.unrouted_stops:
stop.update_value(best_stop)
if best_stop.e > 0 and best_stop.h == 0:
e_no_h = True
if best_stop.h > 0 and best_stop.e == 0:
h_no_e = True
routes.append(current_route)
return list(routes)
