def early_execution(network: STN, realization: dict) -> bool:
## Bookkeeping for events
all_uncontrollables = set(network.uncontrollables)
unused_events = set(network.verts.keys())
not_scheduled = PriorityQueue()
final_schedule = {}
# Mapping from contingent sources to uncontrollables
contingent_pairs = network.contingentEdges.keys()
disabled_uncontrollables = {src: sink for (src, sink) in contingent_pairs}
# Initialize bounds for simulation - starts off with just controllables
# and zero time point
controllable_bounds = find_bounds(network)
true_weight = {}
for event in controllable_bounds:
not_scheduled.push(event, controllable_bounds[0])
true_weight[event] = controllable_bounds[0]
not_scheduled.addOrDecKey(ZERO_ID, 0)
# Run simulation
old_time = 0
while len(unused_events) > 0:
current_time, activated_event = not_scheduled.pop()
# This check ensures that we popped out a valid time_point
# A better way to deal with this would be to just figure out a way to
# increase priorities of elements in a heap
if activated_event in true_weight:
if true_weight[activated_event] > current_time:
continue
unused_events.remove(activated_event)
final_schedule[activated_event] = current_time
assert old_time < current_time, "Chronology violated!"
if activated_event in disabled_uncontrollables:
# If this is a contingent source, we add the associated uncontrollable sink
# to the queue
uncontrollable = disabled_uncontrollables[activated_event]
delay = realization[uncontrollable]
not_scheduled.push(uncontrollable, current_time + delay)
# Update the bounds for all other timepoints
# We only care about events being moved later in time
relevant_edges = network.getEdges(activated_event)
for edge in relevant_edges:
if (edge.j == activated_event) and (edge.i
not in all_uncontrollables):
if needs_early_update(edge, activated_event, current_time,
true_weight):
lower_bound = current_time - edge.Cij
true_weight[edge.i] = lower_bound
# Keep track of this for next iteration of loop
old_time = current_time
# Check if we dispatched succesfully
return emp.scheduleIsValid(network, final_schedule)
