mani_skill.utils.wrappers.frame_stack
=====================================

.. py:module:: mani_skill.utils.wrappers.frame_stack

.. autoapi-nested-parse::

   Wrapper that stacks frames. Adapted from gymnasium package to support GPU vectorizated environments.



Classes
-------

.. autoapisummary::

   mani_skill.utils.wrappers.frame_stack.FrameStack


Module Contents
---------------

.. py:class:: FrameStack(env, num_stack, lz4_compress = False)

   Bases: :py:obj:`gymnasium.ObservationWrapper`


   Observation wrapper that stacks the observations in a rolling manner.

   For example, if the number of stacks is 4, then the returned observation contains
   the most recent 4 observations. For environment 'PickCube-v1', the original observation
   is an array with shape [42], so if we stack 4 observations, the processed observation
   has shape [4, 42].

   This wrapper also supports dict observations, and will stack the leafs of the dictionary accordingly.

   .. note::

      - After :meth:`reset` is called, the frame buffer will be filled with the initial observation.
        I.e. the observation returned by :meth:`reset` will consist of `num_stack` many identical frames.


   .. py:method:: observation(observation)

      Returns a modified observation.

      :param observation: The :attr:`env` observation

      :returns: The modified observation



   .. py:method:: reset(seed=None, options=None)

      Reset the environment with kwargs.

      :param seed: The seed for the environment reset
      :param options: The options for the environment reset

      :returns: The stacked observations



   .. py:method:: step(action)

      Steps through the environment, appending the observation to the frame buffer.

      :param action: The action to step through the environment with

      :returns: Stacked observations, reward, terminated, truncated, and information from the environment



   .. py:property:: base_env
      :type: mani_skill.envs.sapien_env.BaseEnv



   .. py:attribute:: frames


   .. py:attribute:: lz4_compress
      :value: False



   .. py:attribute:: num_stack


   .. py:attribute:: use_dict