def search(self,
start_infoset: TichuState,
iterations: int,
cheat: bool = False) -> TichuAction:
logging.debug(
f"Starting Icarus search for {iterations} iterations; cheating: {cheat}"
)
# initialisation
base_history = self.search_init(start_infoset)
for iteration in range(iterations):
# playout
history = base_history.copy()
root_state = start_infoset.determinization(
observer_id=start_infoset.player_id, cheat=cheat)
state = root_state
while not state.is_terminal():
action = self.policy(history=history, state=state)
history.append(state=state, action=action)
next_state = state.next_state(action, infoset=True)
state = next_state
# state is now terminal
history.append(state=state, action=None)
reward_vector = state.reward_vector()
# backpropagation
for record, capture_context in self.capture(history, root_state):
self.backpropagation(record, capture_context, reward_vector)
return self.best_action(start_infoset)
def search(self,
root_state: TichuState,
observer_id: int,
iterations: int,
cheat: bool = False,
clear_graph_on_new_root=True) -> TichuAction:
logging.debug(
f"started {self.__class__.__name__} with observer {observer_id}, for {iterations} iterations and cheat={cheat}"
)
check_param(observer_id in range(4))
self.observer_id = observer_id
root_nid = self._graph_node_id(root_state)
if root_nid not in self.graph and clear_graph_on_new_root:
_ = self.graph.clear()
else:
logging.debug("Could keep the graph :)")
self.add_root(root_state)
iteration = 0
while iteration < iterations:
iteration += 1
self._init_iteration()
# logging.debug("iteration "+str(iteration))
state = root_state.determinization(observer_id=self.observer_id,
cheat=cheat)
# logging.debug("Tree policy")
leaf_state = self.tree_policy(state)
# logging.debug("rollout")
rollout_result = self.rollout_policy(leaf_state)
# logging.debug("backpropagation")
assert len(rollout_result) == 4
self.backpropagation(reward_vector=rollout_result)
action = self.best_action(root_state)
logging.debug(f"size of graph after search: {len(self.graph)}")
# self._draw_graph('./graphs/graph_{}.pdf'.format(time()))
return action