Episodic life wrapper for gym.Env.

class EpisodicLife(env)

Bases: gym.Wrapper

Inheritance diagram of garage.envs.wrappers.episodic_life.EpisodicLife

Episodic life wrapper for gym.Env.

This wrapper makes episode end when a life is lost, but only reset when all lives are lost.


env – The environment to be wrapped.

step(self, action)

gym.Env step function.

reset(self, **kwargs)

gym.Env reset function.

Reset only when lives are lost.

property spec(self)
classmethod class_name(cls)
render(self, mode='human', **kwargs)

Renders the environment.

The set of supported modes varies per environment. (And some environments do not support rendering at all.) By convention, if mode is:

  • human: render to the current display or terminal and return nothing. Usually for human consumption.

  • rgb_array: Return an numpy.ndarray with shape (x, y, 3), representing RGB values for an x-by-y pixel image, suitable for turning into a video.

  • ansi: Return a string (str) or StringIO.StringIO containing a terminal-style text representation. The text can include newlines and ANSI escape sequences (e.g. for colors).


Make sure that your class’s metadata ‘render.modes’ key includes

the list of supported modes. It’s recommended to call super() in implementations to use the functionality of this method.


mode (str) – the mode to render with


class MyEnv(Env):

metadata = {‘render.modes’: [‘human’, ‘rgb_array’]}

def render(self, mode=’human’):
if mode == ‘rgb_array’:

return np.array(…) # return RGB frame suitable for video

elif mode == ‘human’:

… # pop up a window and render


super(MyEnv, self).render(mode=mode) # just raise an exception


Override close in your subclass to perform any necessary cleanup.

Environments will automatically close() themselves when garbage collected or when the program exits.

seed(self, seed=None)

Sets the seed for this env’s random number generator(s).


Some environments use multiple pseudorandom number generators. We want to capture all such seeds used in order to ensure that there aren’t accidental correlations between multiple generators.


Returns the list of seeds used in this env’s random

number generators. The first value in the list should be the “main” seed, or the value which a reproducer should pass to ‘seed’. Often, the main seed equals the provided ‘seed’, but this won’t be true if seed=None, for example.

Return type


compute_reward(self, achieved_goal, desired_goal, info)
property unwrapped(self)

Completely unwrap this env.


The base non-wrapped gym.Env instance

Return type