Unity 机器学习代理工具包 (ML-Agents) 是一个开源项目,它使游戏和模拟能够作为训练智能代理的环境。
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import logging
import itertools
import numpy as np
from typing import Any, Dict, List, Optional, Tuple, Union
import gym
from gym import error, spaces
from mlagents_envs.environment import UnityEnvironment
from mlagents_envs.base_env import BatchedStepResult
class UnityGymException(error.Error):
"""
Any error related to the gym wrapper of ml-agents.
"""
pass
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("gym_unity")
GymSingleStepResult = Tuple[np.ndarray, float, bool, Dict]
GymMultiStepResult = Tuple[List[np.ndarray], List[float], List[bool], Dict]
GymStepResult = Union[GymSingleStepResult, GymMultiStepResult]
class UnityEnv(gym.Env):
"""
Provides Gym wrapper for Unity Learning Environments.
Multi-agent environments use lists for object types, as done here:
https://github.com/openai/multiagent-particle-envs
"""
def __init__(
self,
environment_filename: str,
worker_id: int = 0,
use_visual: bool = False,
uint8_visual: bool = False,
multiagent: bool = False,
flatten_branched: bool = False,
no_graphics: bool = False,
allow_multiple_visual_obs: bool = False,
):
"""
Environment initialization
:param environment_filename: The UnityEnvironment path or file to be wrapped in the gym.
:param worker_id: Worker number for environment.
:param use_visual: Whether to use visual observation or vector observation.
:param uint8_visual: Return visual observations as uint8 (0-255) matrices instead of float (0.0-1.0).
:param multiagent: Whether to run in multi-agent mode (lists of obs, reward, done).
:param flatten_branched: If True, turn branched discrete action spaces into a Discrete space rather than
MultiDiscrete.
:param no_graphics: Whether to run the Unity simulator in no-graphics mode
:param allow_multiple_visual_obs: If True, return a list of visual observations instead of only one.
"""
self._env = UnityEnvironment(
environment_filename, worker_id, no_graphics=no_graphics
)
# Take a single step so that the brain information will be sent over
if not self._env.get_agent_groups():
self._env.step()
self.visual_obs = None
self._current_state = None
self._n_agents = None
self._multiagent = multiagent
self._flattener = None
# Hidden flag used by Atari environments to determine if the game is over
self.game_over = False
self._allow_multiple_visual_obs = allow_multiple_visual_obs
# Check brain configuration
if len(self._env.get_agent_groups()) != 1:
raise UnityGymException(
"There can only be one brain in a UnityEnvironment "
"if it is wrapped in a gym."
)
self.brain_name = self._env.get_agent_groups()[0]
self.name = self.brain_name
self.group_spec = self._env.get_agent_group_spec(self.brain_name)
if use_visual and self._get_n_vis_obs() == 0:
raise UnityGymException(
"`use_visual` was set to True, however there are no"
" visual observations as part of this environment."
)
self.use_visual = self._get_n_vis_obs() >= 1 and use_visual
if not use_visual and uint8_visual:
logger.warning(
"`uint8_visual was set to true, but visual observations are not in use. "
"This setting will not have any effect."
)
else:
self.uint8_visual = uint8_visual
if self._get_n_vis_obs() > 1 and not self._allow_multiple_visual_obs:
logger.warning(
"The environment contains more than one visual observation. "
"You must define allow_multiple_visual_obs=True to received them all. "
"Otherwise, please note that only the first will be provided in the observation."
)
# Check for number of agents in scene.
self._env.reset()
step_result = self._env.get_step_result(self.brain_name)
self._check_agents(step_result.n_agents())
# Set observation and action spaces
if self.group_spec.is_action_discrete():
branches = self.group_spec.discrete_action_branches
if self.group_spec.action_shape == 1:
self._action_space = spaces.Discrete(branches[0])
else:
if flatten_branched:
self._flattener = ActionFlattener(branches)
self._action_space = self._flattener.action_space
else:
self._action_space = spaces.MultiDiscrete(branches)
else:
if flatten_branched:
logger.warning(
"The environment has a non-discrete action space. It will "
"not be flattened."
)
high = np.array([1] * self.group_spec.action_shape)
self._action_space = spaces.Box(-high, high, dtype=np.float32)
high = np.array([np.inf] * self._get_vec_obs_size())
if self.use_visual:
shape = self._get_vis_obs_shape()
if uint8_visual:
self._observation_space = spaces.Box(
0, 255, dtype=np.uint8, shape=shape
)
else:
self._observation_space = spaces.Box(
0, 1, dtype=np.float32, shape=shape
)
else:
self._observation_space = spaces.Box(-high, high, dtype=np.float32)
def reset(self) -> Union[List[np.ndarray], np.ndarray]:
"""Resets the state of the environment and returns an initial observation.
In the case of multi-agent environments, this is a list.
Returns: observation (object/list): the initial observation of the
space.
"""
self._env.reset()
info = self._env.get_step_result(self.brain_name)
n_agents = info.n_agents()
self._check_agents(n_agents)
self.game_over = False
if not self._multiagent:
res: GymStepResult = self._single_step(info)
else:
res = self._multi_step(info)
return res[0]
def step(self, action: List[Any]) -> GymStepResult:
"""Run one timestep of the environment's dynamics. When end of
episode is reached, you are responsible for calling `reset()`
to reset this environment's state.
Accepts an action and returns a tuple (observation, reward, done, info).
In the case of multi-agent environments, these are lists.
Args:
action (object/list): an action provided by the environment
Returns:
observation (object/list): agent's observation of the current environment
reward (float/list) : amount of reward returned after previous action
done (boolean/list): whether the episode has ended.
info (dict): contains auxiliary diagnostic information, including BatchedStepResult.
"""
# Use random actions for all other agents in environment.
if self._multiagent:
if not isinstance(action, list):
raise UnityGymException(
"The environment was expecting `action` to be a list."
)
if len(action) != self._n_agents:
raise UnityGymException(
"The environment was expecting a list of {} actions.".format(
self._n_agents
)
)
else:
if self._flattener is not None:
# Action space is discrete and flattened - we expect a list of scalars
action = [self._flattener.lookup_action(_act) for _act in action]
action = np.array(action)
else:
if self._flattener is not None:
# Translate action into list
action = self._flattener.lookup_action(action)
spec = self.group_spec
action = np.array(action).reshape((self._n_agents, spec.action_size))
self._env.set_actions(self.brain_name, action)
self._env.step()
info = self._env.get_step_result(self.brain_name)
n_agents = info.n_agents()
self._check_agents(n_agents)
self._current_state = info
if not self._multiagent:
single_res = self._single_step(info)
self.game_over = single_res[2]
return single_res
else:
multi_res = self._multi_step(info)
self.game_over = all(multi_res[2])
return multi_res
def _single_step(self, info: BatchedStepResult) -> GymSingleStepResult:
if self.use_visual:
visual_obs = self._get_vis_obs_list(info)
if self._allow_multiple_visual_obs:
visual_obs_list = []
for obs in visual_obs:
visual_obs_list.append(self._preprocess_single(obs[0]))
self.visual_obs = visual_obs_list
else:
self.visual_obs = self._preprocess_single(visual_obs[0][0])
default_observation = self.visual_obs
else:
default_observation = self._get_vector_obs(info)[0, :]
return (
default_observation,
info.reward[0],
info.done[0],
{"batched_step_result": info},
)
def _preprocess_single(self, single_visual_obs: np.ndarray) -> np.ndarray:
if self.uint8_visual:
return (255.0 * single_visual_obs).astype(np.uint8)
else:
return single_visual_obs
def _multi_step(self, info: BatchedStepResult) -> GymMultiStepResult:
if self.use_visual:
self.visual_obs = self._preprocess_multi(self._get_vis_obs_list(info))
default_observation = self.visual_obs
else:
default_observation = self._get_vector_obs(info)
return (
list(default_observation),
list(info.reward),
list(info.done),
{"batched_step_result": info},
)
def _get_n_vis_obs(self) -> int:
result = 0
for shape in self.group_spec.observation_shapes:
if len(shape) == 3:
result += 1
return result
def _get_vis_obs_shape(self) -> Optional[Tuple]:
for shape in self.group_spec.observation_shapes:
if len(shape) == 3:
return shape
return None
def _get_vis_obs_list(self, step_result: BatchedStepResult) -> List[np.ndarray]:
result: List[np.ndarray] = []
for obs in step_result.obs:
if len(obs.shape) == 4:
result.append(obs)
return result
def _get_vector_obs(self, step_result: BatchedStepResult) -> np.ndarray:
result: List[np.ndarray] = []
for obs in step_result.obs:
if len(obs.shape) == 2:
result.append(obs)
return np.concatenate(result, axis=1)
def _get_vec_obs_size(self) -> int:
result = 0
for shape in self.group_spec.observation_shapes:
if len(shape) == 1:
result += shape[0]
return result
def _preprocess_multi(
self, multiple_visual_obs: List[np.ndarray]
) -> List[np.ndarray]:
if self.uint8_visual:
return [
(255.0 * _visual_obs).astype(np.uint8)
for _visual_obs in multiple_visual_obs
]
else:
return multiple_visual_obs
def render(self, mode="rgb_array"):
return self.visual_obs
def close(self) -> None:
"""Override _close in your subclass to perform any necessary cleanup.
Environments will automatically close() themselves when
garbage collected or when the program exits.
"""
self._env.close()
def seed(self, seed: Any = None) -> None:
"""Sets the seed for this env's random number generator(s).
Currently not implemented.
"""
logger.warning("Could not seed environment %s", self.name)
return
def _check_agents(self, n_agents: int) -> None:
if not self._multiagent and n_agents > 1:
raise UnityGymException(
"The environment was launched as a single-agent environment, however"
"there is more than one agent in the scene."
)
elif self._multiagent and n_agents <= 1:
raise UnityGymException(
"The environment was launched as a mutli-agent environment, however"
"there is only one agent in the scene."
)
if self._n_agents is None:
self._n_agents = n_agents
logger.info("{} agents within environment.".format(n_agents))
elif self._n_agents != n_agents:
raise UnityGymException(
"The number of agents in the environment has changed since "
"initialization. This is not supported."
)
@property
def metadata(self):
return {"render.modes": ["rgb_array"]}
@property
def reward_range(self) -> Tuple[float, float]:
return -float("inf"), float("inf")
@property
def spec(self):
return None
@property
def action_space(self):
return self._action_space
@property
def observation_space(self):
return self._observation_space
@property
def number_agents(self):
return self._n_agents
class ActionFlattener:
"""
Flattens branched discrete action spaces into single-branch discrete action spaces.
"""
def __init__(self, branched_action_space):
"""
Initialize the flattener.
:param branched_action_space: A List containing the sizes of each branch of the action
space, e.g. [2,3,3] for three branches with size 2, 3, and 3 respectively.
"""
self._action_shape = branched_action_space
self.action_lookup = self._create_lookup(self._action_shape)
self.action_space = spaces.Discrete(len(self.action_lookup))
@classmethod
def _create_lookup(self, branched_action_space):
"""
Creates a Dict that maps discrete actions (scalars) to branched actions (lists).
Each key in the Dict maps to one unique set of branched actions, and each value
contains the List of branched actions.
"""
possible_vals = [range(_num) for _num in branched_action_space]
all_actions = [list(_action) for _action in itertools.product(*possible_vals)]
# Dict should be faster than List for large action spaces
action_lookup = {
_scalar: _action for (_scalar, _action) in enumerate(all_actions)
}
return action_lookup
def lookup_action(self, action):
"""
Convert a scalar discrete action into a unique set of branched actions.
:param: action: A scalar value representing one of the discrete actions.
:return: The List containing the branched actions.
"""
return self.action_lookup[action]