# Copyright (c) Microsoft Corporation.
# Licensed under the MIT license.
from typing import Union
import numpy as np
from .abs_explorer import AbsExplorer
[docs]class EpsilonGreedyExplorer(AbsExplorer):
"""Epsilon greedy explorer for discrete action spaces.
Args:
num_actions (int): Number of all possible actions.
"""
def __init__(self, num_actions: int, epsilon: float = .0):
super().__init__()
self._num_actions = num_actions
self._epsilon = epsilon
def __call__(self, action_index: Union[int, np.ndarray]):
if isinstance(action_index, np.ndarray):
return [self._get_exploration_action(act) for act in action_index]
else:
return self._get_exploration_action(action_index)
[docs] def set_parameters(self, *, epsilon: float):
self._epsilon = epsilon
def _get_exploration_action(self, action_index):
assert (action_index < self._num_actions), f"Invalid action: {action_index}"
return action_index if np.random.random() > self._epsilon else np.random.choice(self._num_actions)
