Source code for rl_coach.exploration_policies.additive_noise

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# Copyright (c) 2017 Intel Corporation 
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
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#      http://www.apache.org/licenses/LICENSE-2.0
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from typing import List

import numpy as np

from rl_coach.core_types import RunPhase, ActionType
from rl_coach.exploration_policies.exploration_policy import ExplorationPolicy, ExplorationParameters
from rl_coach.schedules import Schedule, LinearSchedule
from rl_coach.spaces import ActionSpace, BoxActionSpace


# TODO: consider renaming to gaussian sampling
class AdditiveNoiseParameters(ExplorationParameters):
    def __init__(self):
        super().__init__()
        self.noise_percentage_schedule = LinearSchedule(0.1, 0.1, 50000)
        self.evaluation_noise_percentage = 0.05

    @property
    def path(self):
        return 'rl_coach.exploration_policies.additive_noise:AdditiveNoise'


[docs]class AdditiveNoise(ExplorationPolicy): """ AdditiveNoise is an exploration policy intended for continuous action spaces. It takes the action from the agent and adds a Gaussian distributed noise to it. The amount of noise added to the action follows the noise amount that can be given in two different ways: 1. Specified by the user as a noise schedule which is taken in percentiles out of the action space size 2. Specified by the agents action. In case the agents action is a list with 2 values, the 1st one is assumed to be the mean of the action, and 2nd is assumed to be its standard deviation. """ def __init__(self, action_space: ActionSpace, noise_percentage_schedule: Schedule, evaluation_noise_percentage: float): """ :param action_space: the action space used by the environment :param noise_percentage_schedule: the schedule for the noise variance percentage relative to the absolute range of the action space :param evaluation_noise_percentage: the noise variance percentage that will be used during evaluation phases """ super().__init__(action_space) self.noise_percentage_schedule = noise_percentage_schedule self.evaluation_noise_percentage = evaluation_noise_percentage if not isinstance(action_space, BoxActionSpace): raise ValueError("Additive noise exploration works only for continuous controls." "The given action space is of type: {}".format(action_space.__class__.__name__)) if not np.all(-np.inf < action_space.high) or not np.all(action_space.high < np.inf)\ or not np.all(-np.inf < action_space.low) or not np.all(action_space.low < np.inf): raise ValueError("Additive noise exploration requires bounded actions") # TODO: allow working with unbounded actions by defining the noise in terms of range and not percentage def get_action(self, action_values: List[ActionType]) -> ActionType: # TODO-potential-bug consider separating internally defined stdev and externally defined stdev into 2 policies # set the current noise percentage if self.phase == RunPhase.TEST: current_noise_precentage = self.evaluation_noise_percentage else: current_noise_precentage = self.noise_percentage_schedule.current_value # scale the noise to the action space range action_values_std = current_noise_precentage * (self.action_space.high - self.action_space.low) # extract the mean values if isinstance(action_values, list): # the action values are expected to be a list with the action mean and optionally the action stdev action_values_mean = action_values[0].squeeze() else: # the action values are expected to be a numpy array representing the action mean action_values_mean = action_values.squeeze() # step the noise schedule if self.phase is not RunPhase.TEST: self.noise_percentage_schedule.step() # the second element of the list is assumed to be the standard deviation if isinstance(action_values, list) and len(action_values) > 1: action_values_std = action_values[1].squeeze() # add noise to the action means action = np.random.normal(action_values_mean, action_values_std) return action def get_control_param(self): return np.ones(self.action_space.shape)*self.noise_percentage_schedule.current_value