"""Contains a small gymnasium wrapper that can be used to disturb a physics parameter of
a gymnasium environment.
"""
import gymnasium as gym
[docs]class EnvAttributesDisturber(gym.Wrapper):
"""A gymnasium wrapper that can be used to disturb a physics parameter of a
gymnasium environment.
Attributes:
disturbance_label (str): A label for the disturbance that can be used for
logging or plotting. Used in the
:mod:`~stable_learning_control.utils.eval_robustness` utility.
"""
def __init__(self, env, attributes, values):
"""Initialise the EnvAttributesDisturber object.
Args:
env (gym.Env): The gymnasium environment.
attributes (list): A list of attributes to disturb.
values (list): A list of values to set the parameters to.
Raises:
ValueError: The number of parameters and values must be the same.
AttributeError: The parameter does not exist in the environment.
"""
attributes = attributes if isinstance(attributes, list) else [attributes]
values = values if isinstance(values, list) else [values]
super().__init__(env)
# Throw a warning if params and values are not of the same length.
if len(attributes) != len(values):
raise ValueError(
"The number of parameters and values must be the same. "
"Got {} parameters and {} values.".format(len(attributes), len(values))
)
# Try to update the parameter value.
for attribute, value in zip(attributes, values):
try:
setattr(self.env, attribute, value)
except AttributeError:
raise AttributeError(
"The parameter '{}' does not exist in the environment.".format(
attribute
)
)
# Disturbance label.
if len(attributes) == 1:
self.disturbance_label = "{}_{}".format(attributes[0], values[0])
else:
disturbance_label = []
for idx, (attribute, value) in enumerate(zip(attributes, values)):
disturbance_label.append("attr{}_{}".format(idx + 1, round(value, 2)))
self.disturbance_label = "_".join(disturbance_label)