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coach/exploration_policies/boltzmann.py
Gal Leibovich 1d4c3455e7 coach v0.8.0
2017-10-19 13:10:15 +03:00

49 lines
2.1 KiB
Python

#
# Copyright (c) 2017 Intel Corporation
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from exploration_policies.exploration_policy import *
class Boltzmann(ExplorationPolicy):
def __init__(self, tuning_parameters):
"""
:param tuning_parameters: A Preset class instance with all the running paramaters
:type tuning_parameters: Preset
"""
ExplorationPolicy.__init__(self, tuning_parameters)
self.temperature = tuning_parameters.exploration.initial_temperature
self.final_temperature = tuning_parameters.exploration.final_temperature
self.temperature_decay_delta = (
tuning_parameters.exploration.initial_temperature - tuning_parameters.exploration.final_temperature) \
/ float(tuning_parameters.exploration.temperature_decay_steps)
def decay_temperature(self):
if self.temperature > self.final_temperature:
self.temperature -= self.temperature_decay_delta
def get_action(self, action_values):
if self.phase == RunPhase.TRAIN:
self.decay_temperature()
# softmax calculation
exp_probabilities = np.exp(action_values / self.temperature)
probabilities = exp_probabilities / np.sum(exp_probabilities)
probabilities[-1] = 1 - np.sum(probabilities[:-1]) # make sure probs sum to 1
# choose actions according to the probabilities
return np.random.choice(range(self.action_space_size), p=probabilities)
def get_control_param(self):
return self.temperature