Source code for axelrod.strategies.stalker

from axelrod.action import Action
from axelrod.player import Player
from axelrod.strategy_transformers import FinalTransformer

C, D = Action.C, Action.D


[docs]@FinalTransformer((D,), name_prefix=None) # End with defection class Stalker(Player): """ This is a strategy which is only influenced by the score. Its behavior is based on three values: the very_bad_score (all rounds in defection) very_good_score (all rounds in cooperation) wish_score (average between bad and very_good score) It starts with cooperation. - If current_average_score > very_good_score, it defects - If current_average_score lies in (wish_score, very_good_score) it cooperates - If current_average_score > 2, it cooperates - If current_average_score lies in (1, 2) - The remaining case, current_average_score < 1, it behaves randomly. - It defects in the last round Names: - Stalker: [Andre2013]_ """ name = "Stalker" classifier = { "memory_depth": float("inf"), "stochastic": True, "long_run_time": False, "inspects_source": False, "manipulates_source": False, "manipulates_state": False, } def receive_match_attributes(self): R, P, S, T = self.match_attributes["game"].RPST() self.very_good_score = R self.very_bad_score = P self.wish_score = (R + P) / 2 self.current_score = 0 def score_last_round(self, opponent: Player): # Load the default game if not supplied by a tournament. game = self.match_attributes["game"] last_round = (self.history[-1], opponent.history[-1]) scores = game.score(last_round) self.current_score += scores[0] def strategy(self, opponent: Player) -> Action: if len(self.history) == 0: return C self.score_last_round(opponent) current_average_score = self.current_score / len(self.history) if current_average_score > self.very_good_score: return D if (current_average_score > self.wish_score) and ( current_average_score < self.very_good_score ): return C if current_average_score > 2: return C if (current_average_score < 2) and (current_average_score > 1): return D return self._random.random_choice()