diff --git a/gymnasium/vector/vector_env.py b/gymnasium/vector/vector_env.py index fcd5adbbe..31c052507 100644 --- a/gymnasium/vector/vector_env.py +++ b/gymnasium/vector/vector_env.py @@ -30,25 +30,22 @@ class VectorEnv(Generic[ObsType, ActType, ArrayType]): """Base class for vectorized environments to run multiple independent copies of the same environment in parallel. Vector environments can provide a linear speed-up in the steps taken per second through sampling multiple - sub-environments at the same time. To prevent terminated environments waiting until all sub-environments have - terminated or truncated, the vector environments automatically reset sub-environments after they terminate or truncated (within the same step call). - As a result, the step's observation and info are overwritten by the reset's observation and info. - To preserve this data, the observation and info for the final step of a sub-environment is stored in the info parameter, - using `"final_observation"` and `"final_info"` respectively. See :meth:`step` for more information. + sub-environments at the same time. Gymnasium contains two generalised Vector environments: :class:`AsyncVectorEnv` + and :class:`SyncVectorEnv` along with several custom vector environment implementations. + For :func:`reset` and :func:`step` batches `observations`, `rewards`, `terminations`, `truncations` and + `info` for each sub-environment, see the example below. For the `rewards`, `terminations`, and `truncations`, + the data is packaged into a NumPy array of shape `(num_envs,)`. For `observations` (and `actions`, the batching + process is dependent on the type of observation (and action) space, and generally optimised for neural network + input/outputs. For `info`, the data is kept as a dictionary such that a key will give the data for all sub-environment. + + For creating environments, :func:`make_vec` is a vector environment equivalent to :func:`make` for easily creating + vector environments that contains several unique arguments for modifying environment qualities, number of environment, + vectorizer type, vectorizer arguments. - The vector environments batches `observations`, `rewards`, `terminations`, `truncations` and `info` for each - sub-environment. In addition, :meth:`step` expects to receive a batch of actions for each parallel environment. - - Gymnasium contains two generalised Vector environments: :class:`AsyncVectorEnv` and :class:`SyncVectorEnv` along with - several custom vector environment implementations. - - The Vector Environments have the additional attributes for users to understand the implementation - - - :attr:`num_envs` - The number of sub-environment in the vector environment - - :attr:`observation_space` - The batched observation space of the vector environment - - :attr:`single_observation_space` - The observation space of a single sub-environment - - :attr:`action_space` - The batched action space of the vector environment - - :attr:`single_action_space` - The action space of a single sub-environment + Note: + The info parameter of :meth:`reset` and :meth:`step` was originally implemented before v0.25 as a list + of dictionary for each sub-environment. However, this was modified in v0.25+ to be a dictionary with a NumPy + array for each key. To use the old info style, utilise the :class:`DictInfoToList` wrapper. Examples: >>> import gymnasium as gym @@ -56,6 +53,22 @@ class VectorEnv(Generic[ObsType, ActType, ArrayType]): >>> envs = gym.wrappers.vector.ClipReward(envs, min_reward=0.2, max_reward=0.8) >>> envs + >>> envs.num_envs + 3 + >>> envs.action_space + MultiDiscrete([2 2 2]) + >>> envs.observation_space + Box([[-4.80000019e+00 -3.40282347e+38 -4.18879032e-01 -3.40282347e+38 + 0.00000000e+00] + [-4.80000019e+00 -3.40282347e+38 -4.18879032e-01 -3.40282347e+38 + 0.00000000e+00] + [-4.80000019e+00 -3.40282347e+38 -4.18879032e-01 -3.40282347e+38 + 0.00000000e+00]], [[4.80000019e+00 3.40282347e+38 4.18879032e-01 3.40282347e+38 + 5.00000000e+02] + [4.80000019e+00 3.40282347e+38 4.18879032e-01 3.40282347e+38 + 5.00000000e+02] + [4.80000019e+00 3.40282347e+38 4.18879032e-01 3.40282347e+38 + 5.00000000e+02]], (3, 5), float64) >>> observations, infos = envs.reset(seed=123) >>> observations array([[ 0.01823519, -0.0446179 , -0.02796401, -0.03156282, 0. ], @@ -64,7 +77,8 @@ class VectorEnv(Generic[ObsType, ActType, ArrayType]): >>> infos {} >>> _ = envs.action_space.seed(123) - >>> observations, rewards, terminations, truncations, infos = envs.step(envs.action_space.sample()) + >>> actions = envs.action_space.sample() + >>> observations, rewards, terminations, truncations, infos = envs.step(actions) >>> observations array([[ 0.01734283, 0.15089367, -0.02859527, -0.33293587, 1. ], [ 0.02909703, -0.16717631, 0.04740972, 0.3319138 , 1. ], @@ -79,17 +93,18 @@ class VectorEnv(Generic[ObsType, ActType, ArrayType]): {} >>> envs.close() - Note: - The info parameter of :meth:`reset` and :meth:`step` was originally implemented before v0.25 as a list - of dictionary for each sub-environment. However, this was modified in v0.25+ to be a - dictionary with a NumPy array for each key. To use the old info style, utilise the :class:`DictInfoToList` wrapper. + To avoid having to wait for all sub-environments to terminated before resetting, implementations will autoreset + sub-environments on episode end (`terminated or truncated is True`). As a result, when adding observations + to a replay buffer, this requires a knowning where the observation (and info) for each sub-environment are the first + observation from an autoreset. We recommend using an additional variable to store this information. - Note: - All parallel environments should share the identical observation and action spaces. - In other words, a vector of multiple different environments is not supported. + The Vector Environments have the additional attributes for users to understand the implementation - Note: - :func:`make_vec` is the equivalent function to :func:`make` for vector environments. + - :attr:`num_envs` - The number of sub-environment in the vector environment + - :attr:`observation_space` - The batched observation space of the vector environment + - :attr:`single_observation_space` - The observation space of a single sub-environment + - :attr:`action_space` - The batched action space of the vector environment + - :attr:`single_action_space` - The action space of a single sub-environment """ metadata: dict[str, Any] = {} @@ -149,9 +164,8 @@ def step( Batch of (observations, rewards, terminations, truncations, infos) Note: - As the vector environments autoreset for a terminating and truncating sub-environments, - the returned observation and info is not the final step's observation or info which is instead stored in - info as `"final_observation"` and `"final_info"`. + As the vector environments autoreset for a terminating and truncating sub-environments, this will occur on + the next step after `terminated or truncated is True`. Example: >>> import gymnasium as gym