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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from mlagents.envs.base_env import AgentGroupSpec, ActionType, BatchedStepResult
from mlagents.envs.timers import hierarchical_timer, timed
from mlagents.envs.communicator_objects.agent_info_pb2 import AgentInfoProto
from mlagents.envs.communicator_objects.brain_parameters_pb2 import BrainParametersProto
import logging
import numpy as np
import io
from typing import cast, List, Tuple, Union, Collection
from PIL import Image
logger = logging.getLogger("mlagents.envs")
def agent_group_spec_from_proto(
brain_param_proto: BrainParametersProto, agent_info: AgentInfoProto
) -> AgentGroupSpec:
"""
Converts brain parameter and agent info proto to AgentGroupSpec object.
:param brain_param_proto: protobuf object.
:param agent_info: protobuf object.
:return: AgentGroupSpec object.
"""
observation_shape = [tuple(obs.shape) for obs in agent_info.observations]
action_type = (
ActionType.DISCRETE
if brain_param_proto.vector_action_space_type == 0
else ActionType.CONTINUOUS
)
if action_type == ActionType.CONTINUOUS:
action_shape: Union[
int, Tuple[int, ...]
] = brain_param_proto.vector_action_size[0]
else:
action_shape = tuple(brain_param_proto.vector_action_size)
return AgentGroupSpec(observation_shape, action_type, action_shape)
@timed
def process_pixels(image_bytes: bytes, gray_scale: bool) -> np.ndarray:
"""
Converts byte array observation image into numpy array, re-sizes it,
and optionally converts it to grey scale
:param gray_scale: Whether to convert the image to grayscale.
:param image_bytes: input byte array corresponding to image
:return: processed numpy array of observation from environment
"""
with hierarchical_timer("image_decompress"):
image_bytearray = bytearray(image_bytes)
image = Image.open(io.BytesIO(image_bytearray))
# Normally Image loads lazily, this forces it to do loading in the timer scope.
image.load()
s = np.array(image) / 255.0
if gray_scale:
s = np.mean(s, axis=2)
s = np.reshape(s, [s.shape[0], s.shape[1], 1])
return s
@timed
def _process_visual_observation(
obs_index: int,
shape: Tuple[int, int, int],
agent_info_list: Collection[
AgentInfoProto
], # pylint: disable=unsubscriptable-object
) -> np.ndarray:
if len(agent_info_list) == 0:
return np.zeros((0, shape[0], shape[1], shape[2]), dtype=np.float32)
gray_scale = shape[2] == 1
batched_visual = [
process_pixels(agent_obs.observations[obs_index].compressed_data, gray_scale)
for agent_obs in agent_info_list
]
return np.array(batched_visual, dtype=np.float32)
@timed
def _process_vector_observation(
obs_index: int,
shape: Tuple[int, ...],
agent_info_list: Collection[
AgentInfoProto
], # pylint: disable=unsubscriptable-object
) -> np.ndarray:
if len(agent_info_list) == 0:
return np.zeros((0, shape[0]), dtype=np.float32)
np_obs = np.array(
[
agent_obs.observations[obs_index].float_data.data
for agent_obs in agent_info_list
],
dtype=np.float32,
)
# Check for NaNs or infs in the observations
# If there's a NaN in the observations, the np.mean() result will be NaN
# If there's an Inf (either sign) then the result will be Inf
# See https://stackoverflow.com/questions/6736590/fast-check-for-nan-in-numpy for background
# Note that a very large values (larger than sqrt(float_max)) will result in an Inf value here
# This is OK though, worst case it results in an unnecessary (but harmless) nan_to_num call.
d = np.mean(np_obs)
has_nan = np.isnan(d)
has_inf = not np.isfinite(d)
# In we have any NaN or Infs, use np.nan_to_num to replace these with finite values
if has_nan or has_inf:
np_obs = np.nan_to_num(np_obs)
if has_nan:
logger.warning(f"An agent had a NaN observation in the environment")
return np_obs
@timed
def batched_step_result_from_proto(
agent_info_list: Collection[
AgentInfoProto
], # pylint: disable=unsubscriptable-object
group_spec: AgentGroupSpec,
) -> BatchedStepResult:
obs_list: List[np.ndarray] = []
for obs_index, obs_shape in enumerate(group_spec.observation_shapes):
is_visual = len(obs_shape) == 3
if is_visual:
obs_shape = cast(Tuple[int, int, int], obs_shape)
obs_list += [
_process_visual_observation(obs_index, obs_shape, agent_info_list)
]
else:
obs_list += [
_process_vector_observation(obs_index, obs_shape, agent_info_list)
]
rewards = np.array(
[agent_info.reward for agent_info in agent_info_list], dtype=np.float32
)
d = np.dot(rewards, rewards)
has_nan = np.isnan(d)
has_inf = not np.isfinite(d)
# In we have any NaN or Infs, use np.nan_to_num to replace these with finite values
if has_nan or has_inf:
rewards = np.nan_to_num(rewards)
if has_nan:
logger.warning(f"An agent had a NaN reward in the environment")
done = np.array([agent_info.done for agent_info in agent_info_list], dtype=np.bool)
max_step = np.array(
[agent_info.max_step_reached for agent_info in agent_info_list], dtype=np.bool
)
agent_id = np.array(
[agent_info.id for agent_info in agent_info_list], dtype=np.int32
)
action_mask = None
if group_spec.is_action_discrete():
if any([agent_info.action_mask is not None] for agent_info in agent_info_list):
n_agents = len(agent_info_list)
a_size = np.sum(group_spec.discrete_action_branches)
mask_matrix = np.ones((n_agents, a_size), dtype=np.bool)
for agent_index, agent_info in enumerate(agent_info_list):
if agent_info.action_mask is not None:
if len(agent_info.action_mask) == a_size:
mask_matrix[agent_index, :] = [
False if agent_info.action_mask[k] else True
for k in range(a_size)
]
action_mask = (1 - mask_matrix).astype(np.bool)
indices = _generate_split_indices(group_spec.discrete_action_branches)
action_mask = np.split(action_mask, indices, axis=1)
return BatchedStepResult(obs_list, rewards, done, max_step, agent_id, action_mask)
def _generate_split_indices(dims):
if len(dims) <= 1:
return ()
result = (dims[0],)
for i in range(len(dims) - 2):
result += (dims[i + 1] + result[i],)
return result