from mlagents_envs.base_env import ( BehaviorSpec, ActionType, DecisionSteps, TerminalSteps, ) from mlagents_envs.exception import UnityObservationException from mlagents_envs.timers import hierarchical_timer, timed from mlagents_envs.communicator_objects.agent_info_pb2 import AgentInfoProto from mlagents_envs.communicator_objects.observation_pb2 import ( ObservationProto, NONE as COMPRESSION_TYPE_NONE, ) from mlagents_envs.communicator_objects.brain_parameters_pb2 import BrainParametersProto import numpy as np import io from typing import cast, List, Tuple, Union, Collection, Optional, Iterable from PIL import Image PNG_HEADER = b"\x89PNG\r\n\x1a\n" def behavior_spec_from_proto( brain_param_proto: BrainParametersProto, agent_info: AgentInfoProto ) -> BehaviorSpec: """ Converts brain parameter and agent info proto to BehaviorSpec object. :param brain_param_proto: protobuf object. :param agent_info: protobuf object. :return: BehaviorSpec 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 BehaviorSpec(observation_shape, action_type, action_shape) class OffsetBytesIO: """ Simple file-like class that wraps a bytes, and allows moving its "start" position in the bytes. This is only used for reading concatenated PNGs, because Pillow always calls seek(0) at the start of reading. """ __slots__ = ["fp", "offset"] def __init__(self, data: bytes): self.fp = io.BytesIO(data) self.offset = 0 def seek(self, offset: int, whence: int = io.SEEK_SET) -> int: if whence == io.SEEK_SET: res = self.fp.seek(offset + self.offset) return res - self.offset raise NotImplementedError() def tell(self) -> int: return self.fp.tell() - self.offset def read(self, size: int = -1) -> bytes: return self.fp.read(size) def original_tell(self) -> int: """ Returns the offset into the original byte array """ return self.fp.tell() @timed def process_pixels(image_bytes: bytes, expected_channels: int) -> np.ndarray: """ Converts byte array observation image into numpy array, re-sizes it, and optionally converts it to grey scale :param image_bytes: input byte array corresponding to image :param expected_channels: Expected output channels :return: processed numpy array of observation from environment """ image_fp = OffsetBytesIO(image_bytes) if expected_channels == 1: # Convert to grayscale with hierarchical_timer("image_decompress"): image = Image.open(image_fp) # Normally Image loads lazily, load() forces it to do loading in the timer scope. image.load() s = np.array(image, dtype=np.float32) / 255.0 s = np.mean(s, axis=2) s = np.reshape(s, [s.shape[0], s.shape[1], 1]) return s image_arrays = [] # Read the images back from the bytes (without knowing the sizes). while True: with hierarchical_timer("image_decompress"): image = Image.open(image_fp) image.load() image_arrays.append(np.array(image, dtype=np.float32) / 255.0) # Look for the next header, starting from the current stream location try: new_offset = image_bytes.index(PNG_HEADER, image_fp.original_tell()) image_fp.offset = new_offset except ValueError: # Didn't find the header, so must be at the end. break img = np.concatenate(image_arrays, axis=2) # We can drop additional channels since they may need to be added to include # numbers of observation channels not divisible by 3. actual_channels = list(img.shape)[2] if actual_channels > expected_channels: img = img[..., 0:expected_channels] return img @timed def observation_to_np_array( obs: ObservationProto, expected_shape: Optional[Iterable[int]] = None ) -> np.ndarray: """ Converts observation proto into numpy array of the appropriate size. :param obs: observation proto to be converted :param expected_shape: optional shape information, used for sanity checks. :return: processed numpy array of observation from environment """ if expected_shape is not None: if list(obs.shape) != list(expected_shape): raise UnityObservationException( f"Observation did not have the expected shape - got {obs.shape} but expected {expected_shape}" ) expected_channels = obs.shape[2] if obs.compression_type == COMPRESSION_TYPE_NONE: img = np.array(obs.float_data.data, dtype=np.float32) img = np.reshape(img, obs.shape) return img else: img = process_pixels(obs.compressed_data, expected_channels) # Compare decompressed image size to observation shape and make sure they match if list(obs.shape) != list(img.shape): raise UnityObservationException( f"Decompressed observation did not have the expected shape - " f"decompressed had {img.shape} but expected {obs.shape}" ) return img @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) batched_visual = [ observation_to_np_array(agent_obs.observations[obs_index], shape) for agent_obs in agent_info_list ] return np.array(batched_visual, dtype=np.float32) def _raise_on_nan_and_inf(data: np.array, source: str) -> np.array: # Check for NaNs or Infinite values in the observation or reward data. # If there's a NaN in the observations, the np.mean() result will be NaN # If there's an Infinite value (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 # Raise a Runtime error in the case that NaNs or Infinite values make it into the data. if data.size == 0: return data d = np.mean(data) has_nan = np.isnan(d) has_inf = not np.isfinite(d) if has_nan: raise RuntimeError(f"The {source} provided had NaN values.") if has_inf: raise RuntimeError(f"The {source} provided had Infinite values.") @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, ) _raise_on_nan_and_inf(np_obs, "observations") return np_obs @timed def steps_from_proto( agent_info_list: Collection[ AgentInfoProto ], # pylint: disable=unsubscriptable-object behavior_spec: BehaviorSpec, ) -> Tuple[DecisionSteps, TerminalSteps]: decision_agent_info_list = [ agent_info for agent_info in agent_info_list if not agent_info.done ] terminal_agent_info_list = [ agent_info for agent_info in agent_info_list if agent_info.done ] decision_obs_list: List[np.ndarray] = [] terminal_obs_list: List[np.ndarray] = [] for obs_index, obs_shape in enumerate(behavior_spec.observation_shapes): is_visual = len(obs_shape) == 3 if is_visual: obs_shape = cast(Tuple[int, int, int], obs_shape) decision_obs_list.append( _process_visual_observation( obs_index, obs_shape, decision_agent_info_list ) ) terminal_obs_list.append( _process_visual_observation( obs_index, obs_shape, terminal_agent_info_list ) ) else: decision_obs_list.append( _process_vector_observation( obs_index, obs_shape, decision_agent_info_list ) ) terminal_obs_list.append( _process_vector_observation( obs_index, obs_shape, terminal_agent_info_list ) ) decision_rewards = np.array( [agent_info.reward for agent_info in decision_agent_info_list], dtype=np.float32 ) terminal_rewards = np.array( [agent_info.reward for agent_info in terminal_agent_info_list], dtype=np.float32 ) _raise_on_nan_and_inf(decision_rewards, "rewards") _raise_on_nan_and_inf(terminal_rewards, "rewards") max_step = np.array( [agent_info.max_step_reached for agent_info in terminal_agent_info_list], dtype=np.bool, ) decision_agent_id = np.array( [agent_info.id for agent_info in decision_agent_info_list], dtype=np.int32 ) terminal_agent_id = np.array( [agent_info.id for agent_info in terminal_agent_info_list], dtype=np.int32 ) action_mask = None if behavior_spec.is_action_discrete(): if any( [agent_info.action_mask is not None] for agent_info in decision_agent_info_list ): n_agents = len(decision_agent_info_list) a_size = np.sum(behavior_spec.discrete_action_branches) mask_matrix = np.ones((n_agents, a_size), dtype=np.bool) for agent_index, agent_info in enumerate(decision_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(behavior_spec.discrete_action_branches) action_mask = np.split(action_mask, indices, axis=1) return ( DecisionSteps( decision_obs_list, decision_rewards, decision_agent_id, action_mask ), TerminalSteps(terminal_obs_list, terminal_rewards, max_step, terminal_agent_id), ) 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