def calculate_transition_costs(self, source, targets):
if not targets:
return []
# All measurements in targets should be the same, since they
# are grouped by measurement ID
target_measurement = targets[0].measurement
max_route_distance = self.calculate_max_route_distance(
source.measurement, target_measurement)
route_results = road_routing.road_network_route_many(
(source.edge, source.location),
[(tc.edge, tc.location) for tc in targets],
self.get_road_edges,
max_path_cost=max_route_distance)
# Geodesic distance based on WGS 84 spheroid
great_circle_distance = vincenty(
(source.measurement.lat, source.measurement.lon),
(target_measurement.lat, target_measurement.lon)).meters
costs = []
for target, (path, route_distance) in zip(targets, route_results):
if route_distance < 0:
# Not reachable
costs.append(-1)
continue
target.path[source] = path
if ALGORITHM.name == 'HMM':
# delta = abs(math.log(max(1, route_distance)) - math.log(max(1, great_circle_distance)))
delta = abs(route_distance - great_circle_distance)
costs.append(delta / self.beta)
elif ALGORITHM.name == 'ST':
delta = abs(
math.log(max(1, route_distance)) -
math.log(max(1, great_circle_distance)))
costs.append(delta)
elif ALGORITHM.name == 'FV':
delta = 2 * self.sigma_z * self.sigma_z * route_distance / self.beta
costs.append(delta)
# They should be equivalent (only for testing):
# for cost, target in zip(costs, targets):
# single_cost = self.calculate_transition_cost(source, target)
# assert abs(cost - single_cost) < 0.0000001
return costs
def calculate_transition_costs(self, source, targets):
if not targets:
return []
# All measurements in targets should be the same, since they
# are grouped by measurement ID
target_measurement = targets[0].measurement
max_route_distance = self.calculate_max_route_distance(
source.measurement, target_measurement)
route_results = road_routing.road_network_route_many(
(source.edge, source.location),
[(tc.edge, tc.location) for tc in targets],
self.get_road_edges,
max_path_cost=max_route_distance)
# Geodesic distance based on WGS 84 spheroid
great_circle_distance = distance.vincenty(
(source.measurement.lat, source.measurement.lon),
(target_measurement.lat, target_measurement.lon)).meters
costs = []
for target, (path, route_distance) in zip(targets, route_results):
if route_distance < 0:
# Not reachable
costs.append(-1)
continue
target.path[source] = path
delta = abs(route_distance - great_circle_distance)
costs.append(math.exp(-delta / self.beta) / self.beta)
# They should be equivalent (only for testing):
# for cost, target in zip(costs, targets):
# single_cost = self.calculate_transition_cost(source, target)
# assert abs(cost - single_cost) < 0.0000001
return costs