def get_action(self, state: GameState) -> GameAction:
# Very similar to greedy agent get action, but now instead of picking an action with highest value we pick
# action with highest avg value, so in avg our snake will do good
best_actions = state.get_possible_actions(player_index=self.player_index)
best_value = -np.inf
for action in state.get_possible_actions(player_index=self.player_index):
avg_value = 0
actions_len = 0
for opponents_actions in state.get_possible_actions_dicts_given_action(action,
player_index=self.player_index):
opponents_actions[self.player_index] = action
next_state = get_next_state(state, opponents_actions)
h_value = _heuristic_for_tournament(next_state, self.player_index)
avg_value += h_value
actions_len += 1
if len(state.opponents_alive) > 2:
# consider only 1 possible opponents actions to reduce time & memory:
break
avg_value /= actions_len
# choosing action according to the avg value we got preforming this action
if avg_value > best_value:
best_value = avg_value
best_actions = [action]
elif avg_value == best_value:
best_actions.append(action)
return np.random.choice(best_actions)
def get_action(self, state: GameState) -> GameAction:
# init with all possible actions for the case where the agent is alone. it will (possibly) be overridden later
start = time.time()
best_actions = state.get_possible_actions(
player_index=self.player_index)
best_value = -np.inf
for action in state.get_possible_actions(
player_index=self.player_index):
for opponents_actions in state.get_possible_actions_dicts_given_action(
action, player_index=self.player_index):
opponents_actions[self.player_index] = action
next_state = get_next_state(state, opponents_actions)
h_value = self._heuristic(next_state)
if h_value > best_value:
best_value = h_value
best_actions = [action]
elif h_value == best_value:
best_actions.append(action)
if len(state.opponents_alive) > 2:
# consider only 1 possible opponents actions to reduce time & memory:
break
end = time.time()
self.counter_steps += 1
self.avg_time = ((end - start) + self.avg_time *
(self.counter_steps - 1)) / self.counter_steps
return np.random.choice(best_actions)
def heuristic(state: GameState, player_index: int) -> float:
"""
Computes the heuristic value for the agent with player_index at the given state
:param state:
:param player_index: integer. represents the identity of the player. this is the index of the agent's snake in the
state.snakes array as well.
:return:
"""
#c
if not state.snakes[player_index].alive: #we never want our snake to die
return -500
#setting weights
too_long = 8
fruit_weight = 1.4
weight_for_length = 500
board_factor = np.sqrt(state.board_size.width**2 +
state.board_size.height**2)
snake_length = state.snakes[player_index].length
turns_left = (state.game_duration_in_turns - state.turn_number)
possible_fruits = min(
len(state.fruits_locations) +
sum([s.length for s in state.snakes if s.alive]), turns_left)
if (possible_fruits > 0):
bonus_for_length = weight_for_length * snake_length / possible_fruits
else:
bonus_for_length = weight_for_length
#calculating manheten distance and normalizing for board
bonus_for_avoiding_tail = cityblock(
state.snakes[player_index].head,
state.snakes[player_index].tail_position) / np.sqrt(
state.board_size.width**2 + state.board_size.height**2)
avoiding_tail_weight = 1 - 1 / snake_length if snake_length > too_long else 0
bonus_for_avoiding_tail *= avoiding_tail_weight
#distinguishing between two game modes eating fruits and surviving
if len(state.fruits_locations) > 0:
nearest_fruits_weight = min([
cityblock(state.snakes[player_index].head, trophy_i)
for trophy_i in state.fruits_locations
])
nearest_fruit_bonus = state.board_size.height + state.board_size.width - nearest_fruits_weight
nearest_fruit_bonus /= (state.board_size.height +
state.board_size.width) #normalize
nearest_fruit_bonus *= fruit_weight
return nearest_fruit_bonus + bonus_for_length + avoiding_tail_weight
else:
weight = 1.8
distance_from_enemy_bonus = min(
cityblock(state.snakes[player_index].head,
state.snakes[enemy].head)
for enemy in state.get_opponents_alive(player_index)) if len(
state.get_opponents_alive(player_index)) > 0 else 0
distance_from_enemy_bonus /= board_factor #normalize
return bonus_for_length * weight + bonus_for_avoiding_tail * weight + distance_from_enemy_bonus
def get_action(self, state: GameState) -> GameAction:
best_value = -np.inf
best_actions = state.get_possible_actions(player_index=self.player_index)
for action in state.get_possible_actions(player_index=self.player_index):
next_state = self.TurnBasedGameState(state, action)
max_value = self.RB_minimax(next_state, state.depth-1)
if max_value > best_value:
best_value = max_value
best_actions = [action]
elif best_value == max_value:
best_actions.append(action)
return np.random.choice(best_actions)
def get_action(self, state: GameState) -> GameAction:
max_value = np.NINF
best_action = None
for action in state.get_possible_actions(self.player_index):
value = self.rb_minimax(self.TurnBasedGameState(state, action), 2)
max_value = max(max_value, value)
best_action = action if max_value == value else best_action
return best_action
def get_action(self, state: GameState) -> GameAction:
if self.is_trap(state):
return self.trap_escape(state)
# init with all possible actions for the case where the agent is alone. it will (possibly) be overridden later
best_actions = state.get_possible_actions(
player_index=self.player_index)
best_value = -np.inf
for action in state.get_possible_actions(
player_index=self.player_index):
for opponents_actions in state.get_possible_actions_dicts_given_action(
action, player_index=self.player_index):
opponents_actions[self.player_index] = action
next_state = get_next_state(state, opponents_actions)
h_value = self.tournament_heuristic(next_state)
if h_value > best_value:
best_value = h_value
best_actions = [action]
elif h_value == best_value:
best_actions.append(action)
return np.random.choice(best_actions)
def get_action(self, state: GameState) -> GameAction:
game_state = self.TurnBasedGameState(state, None)
actions = state.get_possible_actions(player_index=self.player_index)
best_action = GameAction.STRAIGHT # default action. will be changed
best_value = -np.inf
for action in actions:
game_state.agent_action = action
value = self._RB_alpha_beta(game_state, self.Turn.OPPONENTS_TURN,
self.DEPTH, -np.inf, np.inf)
if value > best_value:
best_action = action
best_value = value
return best_action
def get_action(self, state: GameState) -> GameAction:
cur_time = time.clock()
cur_max = -np.inf
max_state = GameAction(1)
for action in state.get_possible_actions(self.player_index):
state_after_turn = MinimaxAgent.TurnBasedGameState(state, action)
state_value = self.__RB_Minimax__(state_after_turn, 2)
if state_value > cur_max:
cur_max = state_value
max_state = action
end_time = time.clock()
self.time += end_time - cur_time
self.num_played += 1
return max_state
def get_action(self, state: GameState) -> GameAction:
if self.curr_turn is None:
self.curr_turn = self.TurnBasedGameState(state, None)
best_value = -np.inf
best_actions = []
self.curr_turn.curr_turn = MinimaxAgent.Turn.OPPONENTS_TURN
for our_action in state.get_possible_actions(
player_index=self.player_index):
h_value = self.minimax(self.TurnBasedGameState(state, our_action),
2)
if h_value > best_value:
best_value = h_value
best_actions = [our_action]
elif h_value == best_value:
best_actions.append(our_action)
return np.random.choice(best_actions)
def get_action(self, state: GameState) -> GameAction:
# Insert your code here...
max_actions = []
best_value = -np.inf
for action in state.get_possible_actions(
player_index=self.player_index):
turn_next_state = MinimaxAgent.TurnBasedGameState(state, action)
min_max_value = self.alpha_beta_value(turn_next_state,
MinimaxAgent.Turn.AGENT_TURN,
2, float('-inf'),
float('inf'))
if min_max_value > best_value:
best_value = min_max_value
max_actions = [action]
elif min_max_value == best_value:
max_actions.append(action)
return np.random.choice(max_actions)
def get_action(self, state: GameState) -> GameAction:
# Insert your code here...
start = time.time()
choose_max = -np.inf
max_action = GameAction.LEFT
for agent_action in state.get_possible_actions(
player_index=self.player_index):
head_tree = self.TurnBasedGameState(
state, agent_action) #possible opponent action
current_action_max = self.minimax(head_tree, 1)
#print(choose_max, curr_result, "\n")
if choose_max < current_action_max:
choose_max = current_action_max
max_action = agent_action
end = time.time()
self.counter_steps += 1
self.avg_time = ((end - start) + self.avg_time *
(self.counter_steps - 1)) / self.counter_steps
return max_action
pass
def get_action(self, state: GameState) -> GameAction:
start_time = time.clock()
max_value = -np.inf
maxi_action = GameAction(0)
all_actions = state.get_possible_actions(self.player_index)
for action in all_actions:
curr_value = self.get_action_wrapper(
MinimaxAgent.TurnBasedGameState(state, action), self.dep,
-np.inf, np.inf)
if curr_value > max_value:
max_value = curr_value
maxi_action = action
stop_time = time.clock()
#environment.time_elapsed += stop_time - start_time
self.time += stop_time - start_time
self.num_played += 1
avg_turn = self.time / self.num_played
if ((avg_turn) > 60 / 500 and self.dep > 2):
self.dep -= 1
elif (
(avg_turn) < 45 / 500
): #if we have extra time we can allow ourselves to allow more depth
self.dep += 1
return maxi_action
def get_action(self, state: GameState) -> GameAction:
D_arr = [2, 3, 4]
best_value = -np.inf
best_actions = []
i = 0
for our_action in state.get_possible_actions(
player_index=self.player_index):
t = time.time()
h_value = self.abminimax(
self.TurnBasedGameState(state, our_action), D_arr[i], -np.inf,
np.inf)
elapsed = time.time() - t
if elapsed < 15 and i < 2:
i += 1
if elapsed > 20 and i > 0:
i -= 1
# elif elapsed
if h_value > best_value:
best_value = h_value
best_actions = [our_action]
elif h_value == best_value:
best_actions.append(our_action)
return np.random.choice(best_actions)
def _get_reachable_area(state: GameState, player_index: int) -> float:
snake = state.snakes[player_index]
# gets the boards of player index snake positions
snake_board = state.get_board(player_index)[0]
# dfs will find the area reachable
return _dfs(snake_board, snake.head, True)
def heuristic(state: GameState, player_index: int) -> float:
"""
Computes the heuristic value for the agent with player_index at the given state
:param state:
:param player_index: integer. represents the identity of the player. this is the index of the agent's snake in the
state.snakes array as well.
:return:
"""
# Insert your code here...
if not state.snakes[player_index].alive:
return state.snakes[player_index].length
discount_factor = 0.5
max_possible_fruits = len(state.fruits_locations) + sum([
s.length for s in state.snakes if s.index != player_index and s.alive
])
turns_left = (state.game_duration_in_turns - state.turn_number)
max_possible_fruits = min(max_possible_fruits, turns_left)
optimistic_future_reward = discount_factor * (
1 - discount_factor**max_possible_fruits) / (1 - discount_factor)
original_greedy_value = state.snakes[
player_index].length + optimistic_future_reward
best_dist = state.board_size.width + state.board_size.height
for fruit in state.fruits_locations:
d_x = abs(state.snakes[player_index].head[0] - fruit[0])
d_y = abs(state.snakes[player_index].head[1] - fruit[1])
manhattan_dist = d_x + d_y
if 0 <= manhattan_dist < best_dist:
best_dist = manhattan_dist
# better bonus for lower best_dist
if best_dist != 0:
bonus_dist_fruit = optimistic_future_reward / best_dist
else:
bonus_dist_fruit = optimistic_future_reward
# better bonus if next state isn't a border
bonus_border = 0
head_x = state.snakes[player_index].head[0]
head_y = state.snakes[player_index].head[1]
radios = 1
if not state.is_within_grid_boundaries((head_x + radios, head_y)) or not state.is_within_grid_boundaries((head_x, head_y+radios))\
or not state.is_within_grid_boundaries((head_x - radios, head_y)) or not state.is_within_grid_boundaries((head_x, head_y-radios)):
bonus_border -= optimistic_future_reward / (best_dist + radios)
# if next move isn't a snake's body then bonus 0 else minus optimistic_future_reward
bonus_is_snake_in_cell = 0
for s in state.snakes:
if not s.index == player_index:
if s.is_in_cell((head_x + radios, head_y)) or s.is_in_cell((head_x, head_y + radios)) \
or s.is_in_cell((head_x - radios, head_y)) or s.is_in_cell((head_x, head_y - radios)):
bonus_border -= optimistic_future_reward / (best_dist)
break
elif state.snakes[player_index].is_in_cell((head_x+radios, head_y)) or \
state.snakes[player_index].is_in_cell((head_x, head_y+radios))\
or state.snakes[player_index].is_in_cell((head_x - radios, head_y)) \
or state.snakes[player_index].is_in_cell((head_x, head_y - radios)):
bonus_border -= optimistic_future_reward
break
ret_h_val = float(original_greedy_value + bonus_dist_fruit + bonus_border +
bonus_is_snake_in_cell)
return ret_h_val