ray/rllib/utils/exploration/per_worker_gaussian_noise.py

45 lines
1.8 KiB
Python

from gym.spaces import Space
from typing import Optional
from ray.rllib.utils.exploration.gaussian_noise import GaussianNoise
from ray.rllib.utils.schedules import ConstantSchedule
class PerWorkerGaussianNoise(GaussianNoise):
"""A per-worker Gaussian noise class for distributed algorithms.
Sets the `scale` schedules of individual workers to a constant:
0.4 ^ (1 + [worker-index] / float([num-workers] - 1) * 7)
See Ape-X paper.
"""
def __init__(self, action_space: Space, *, framework: Optional[str],
num_workers: Optional[int], worker_index: Optional[int],
**kwargs):
"""
Args:
action_space (Space): The gym action space used by the environment.
num_workers (Optional[int]): The overall number of workers used.
worker_index (Optional[int]): The index of the Worker using this
Exploration.
framework (Optional[str]): One of None, "tf", "torch".
"""
scale_schedule = None
# Use a fixed, different epsilon per worker. See: Ape-X paper.
if num_workers > 0:
if worker_index > 0:
num_workers_minus_1 = float(num_workers - 1) \
if num_workers > 1 else 1.0
exponent = (1 + (worker_index / num_workers_minus_1) * 7)
scale_schedule = ConstantSchedule(
0.4**exponent, framework=framework)
# Local worker should have zero exploration so that eval
# rollouts run properly.
else:
scale_schedule = ConstantSchedule(0.0, framework=framework)
super().__init__(
action_space,
scale_schedule=scale_schedule,
framework=framework,
**kwargs)