Source code for axelrod.strategies.selfsteem

from math import pi, sin

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

C, D = Action.C, Action.D




class SelfSteem(Player):
    """
    This strategy is based on the feeling with the same name.
    It is modeled on the sine curve(f = sin( 2* pi * n / 10 )), which varies
    with the current iteration.

    If f > 0.95, 'ego' of the algorithm is inflated; always defects.
    If 0.95 > abs(f) > 0.3, rational behavior; follows TitForTat algortithm.
    If 0.3 > f > -0.3; random behavior.
    If f < -0.95, algorithm is at rock bottom; always cooperates.

    Futhermore, the algorithm implements a retaliation policy, if the opponent
    defects; the sin curve is shifted. But due to lack of further information,
    this implementation does not include a sin phase change.
    Names:

    - SelfSteem: [Andre2013]_
    """

    name = "SelfSteem"
    classifier = {
        "memory_depth": float("inf"),
        "stochastic": True,
        "long_run_time": False,
        "inspects_source": False,
        "manipulates_source": False,
        "manipulates_state": False,
    }



    def strategy(self, opponent: Player) -> Action:
        """Actual strategy definition that determines player's action."""
        turns_number = len(self.history)
        sine_value = sin(2 * pi * turns_number / 10)

        if sine_value > 0.95:
            return D

        if 0.95 > abs(sine_value) > 0.3:
            return opponent.history[-1]

        if 0.3 > sine_value > -0.3:
            return self._random.random_choice()

        return C