ray/rllib/utils/schedules/polynomial_schedule.py

46 lines
1.6 KiB
Python

from ray.rllib.utils.schedules.schedule import Schedule
from ray.rllib.utils.framework import try_import_tf
tf = try_import_tf()
class PolynomialSchedule(Schedule):
def __init__(self,
schedule_timesteps,
final_p,
initial_p=1.0,
power=2.0,
framework=None):
"""
Polynomial interpolation between initial_p and final_p over
schedule_timesteps. After this many time steps always `final_p` is
returned.
Agrs:
schedule_timesteps (int): Number of time steps for which to
linearly anneal initial_p to final_p
final_p (float): Final output value.
initial_p (float): Initial output value.
framework (Optional[str]): One of "tf", "torch", or None.
"""
super().__init__(framework=framework)
assert schedule_timesteps > 0
self.schedule_timesteps = schedule_timesteps
self.final_p = final_p
self.initial_p = initial_p
self.power = power
def value(self, t):
"""
Returns the result of:
final_p + (initial_p - final_p) * (1 - `t`/t_max) ** power
"""
if self.framework == "tf" and tf.executing_eagerly() is False:
return tf.train.polynomial_decay(
learning_rate=self.initial_p,
global_step=t,
decay_steps=self.schedule_timesteps,
end_learning_rate=self.final_p,
power=self.power)
return self.final_p + (self.initial_p - self.final_p) * (
1.0 - (t / self.schedule_timesteps))**self.power