from typing import Callable, List, Dict, Tuple, Optional, Union import abc from mlagents.torch_utils import torch, nn from mlagents_envs.base_env import ActionSpec, ObservationSpec, ObservationType from mlagents.trainers.torch.action_model import ActionModel from mlagents.trainers.torch.agent_action import AgentAction from mlagents.trainers.torch.action_log_probs import ActionLogProbs from mlagents.trainers.settings import NetworkSettings, EncoderType, ConditioningType from mlagents.trainers.torch.utils import ModelUtils from mlagents.trainers.torch.decoders import ValueHeads from mlagents.trainers.torch.layers import LSTM, LinearEncoder from mlagents.trainers.torch.encoders import VectorInput from mlagents.trainers.buffer import AgentBuffer from mlagents.trainers.trajectory import ObsUtil from mlagents.trainers.torch.conditioning import ConditionalEncoder from mlagents.trainers.torch.attention import ( EntityEmbedding, ResidualSelfAttention, get_zero_entities_mask, ) from mlagents.trainers.exception import UnityTrainerException ActivationFunction = Callable[[torch.Tensor], torch.Tensor] EncoderFunction = Callable[ [torch.Tensor, int, ActivationFunction, int, str, bool], torch.Tensor ] EPSILON = 1e-7 class ObservationEncoder(nn.Module): def __init__( self, observation_specs: List[ObservationSpec], h_size: int, vis_encode_type: EncoderType, normalize: bool = False, ): """ Returns an ObservationEncoder that can process and encode a set of observations. Will use an RSA if needed for variable length observations. """ super().__init__() self.processors, self.embedding_sizes = ModelUtils.create_input_processors( observation_specs, h_size, vis_encode_type, normalize=normalize ) self.rsa, self.x_self_encoder = ModelUtils.create_residual_self_attention( self.processors, self.embedding_sizes, h_size ) if self.rsa is not None: total_enc_size = sum(self.embedding_sizes) + h_size else: total_enc_size = sum(self.embedding_sizes) self.normalize = normalize self._total_enc_size = total_enc_size self._total_goal_enc_size = 0 self._goal_processor_indices: List[int] = [] for i in range(len(observation_specs)): if observation_specs[i].observation_type == ObservationType.GOAL_SIGNAL: self._total_goal_enc_size += self.embedding_sizes[i] self._goal_processor_indices.append(i) @property def total_enc_size(self) -> int: """ Returns the total encoding size for this ObservationEncoder. """ return self._total_enc_size @property def total_goal_enc_size(self) -> int: """ Returns the total goal encoding size for this ObservationEncoder. """ return self._total_goal_enc_size def update_normalization(self, buffer: AgentBuffer) -> None: obs = ObsUtil.from_buffer(buffer, len(self.processors)) for vec_input, enc in zip(obs, self.processors): if isinstance(enc, VectorInput): enc.update_normalization(torch.as_tensor(vec_input)) def copy_normalization(self, other_encoder: "ObservationEncoder") -> None: if self.normalize: for n1, n2 in zip(self.processors, other_encoder.processors): if isinstance(n1, VectorInput) and isinstance(n2, VectorInput): n1.copy_normalization(n2) def forward(self, inputs: List[torch.Tensor]) -> torch.Tensor: """ Encode observations using a list of processors and an RSA. :param inputs: List of Tensors corresponding to a set of obs. """ encodes = [] var_len_processor_inputs: List[Tuple[nn.Module, torch.Tensor]] = [] for idx, processor in enumerate(self.processors): if not isinstance(processor, EntityEmbedding): # The input can be encoded without having to process other inputs obs_input = inputs[idx] processed_obs = processor(obs_input) encodes.append(processed_obs) else: var_len_processor_inputs.append((processor, inputs[idx])) if len(encodes) != 0: encoded_self = torch.cat(encodes, dim=1) input_exist = True else: input_exist = False if len(var_len_processor_inputs) > 0 and self.rsa is not None: # Some inputs need to be processed with a variable length encoder masks = get_zero_entities_mask([p_i[1] for p_i in var_len_processor_inputs]) embeddings: List[torch.Tensor] = [] processed_self = ( self.x_self_encoder(encoded_self) if input_exist and self.x_self_encoder is not None else None ) for processor, var_len_input in var_len_processor_inputs: embeddings.append(processor(processed_self, var_len_input)) qkv = torch.cat(embeddings, dim=1) attention_embedding = self.rsa(qkv, masks) if not input_exist: encoded_self = torch.cat([attention_embedding], dim=1) input_exist = True else: encoded_self = torch.cat([encoded_self, attention_embedding], dim=1) if not input_exist: raise UnityTrainerException( "The trainer was unable to process any of the provided inputs. " "Make sure the trained agents has at least one sensor attached to them." ) return encoded_self def get_goal_encoding(self, inputs: List[torch.Tensor]) -> torch.Tensor: """ Encode observations corresponding to goals using a list of processors. :param inputs: List of Tensors corresponding to a set of obs. """ encodes = [] for idx in self._goal_processor_indices: processor = self.processors[idx] if not isinstance(processor, EntityEmbedding): # The input can be encoded without having to process other inputs obs_input = inputs[idx] processed_obs = processor(obs_input) encodes.append(processed_obs) else: raise UnityTrainerException( "The one of the goals uses variable length observations. This use " "case is not supported." ) if len(encodes) != 0: encoded = torch.cat(encodes, dim=1) else: raise UnityTrainerException( "Trainer was unable to process any of the goals provided as input." ) return encoded class NetworkBody(nn.Module): def __init__( self, observation_specs: List[ObservationSpec], network_settings: NetworkSettings, encoded_act_size: int = 0, ): super().__init__() self.normalize = network_settings.normalize self.use_lstm = network_settings.memory is not None self.h_size = network_settings.hidden_units self.m_size = ( network_settings.memory.memory_size if network_settings.memory is not None else 0 ) self.observation_encoder = ObservationEncoder( observation_specs, self.h_size, network_settings.vis_encode_type, self.normalize, ) self.processors = self.observation_encoder.processors total_enc_size = self.observation_encoder.total_enc_size total_enc_size += encoded_act_size if ( self.observation_encoder.total_goal_enc_size > 0 and network_settings.goal_conditioning_type == ConditioningType.HYPER ): self._body_endoder = ConditionalEncoder( total_enc_size, self.observation_encoder.total_goal_enc_size, self.h_size, network_settings.num_layers, 1, ) else: self._body_endoder = LinearEncoder( total_enc_size, network_settings.num_layers, self.h_size ) if self.use_lstm: self.lstm = LSTM(self.h_size, self.m_size) else: self.lstm = None # type: ignore def update_normalization(self, buffer: AgentBuffer) -> None: self.observation_encoder.update_normalization(buffer) def copy_normalization(self, other_network: "NetworkBody") -> None: self.observation_encoder.copy_normalization(other_network.observation_encoder) @property def memory_size(self) -> int: return self.lstm.memory_size if self.use_lstm else 0 def forward( self, inputs: List[torch.Tensor], actions: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[torch.Tensor, torch.Tensor]: encoded_self = self.observation_encoder(inputs) if actions is not None: encoded_self = torch.cat([encoded_self, actions], dim=1) if isinstance(self._body_endoder, ConditionalEncoder): goal = self.observation_encoder.get_goal_encoding(inputs) encoding = self._body_endoder(encoded_self, goal) else: encoding = self._body_endoder(encoded_self) if self.use_lstm: # Resize to (batch, sequence length, encoding size) encoding = encoding.reshape([-1, sequence_length, self.h_size]) encoding, memories = self.lstm(encoding, memories) encoding = encoding.reshape([-1, self.m_size // 2]) return encoding, memories class MultiAgentNetworkBody(torch.nn.Module): """ A network body that uses a self attention layer to handle state and action input from a potentially variable number of agents that share the same observation and action space. """ def __init__( self, observation_specs: List[ObservationSpec], network_settings: NetworkSettings, action_spec: ActionSpec, ): super().__init__() self.normalize = network_settings.normalize self.use_lstm = network_settings.memory is not None self.h_size = network_settings.hidden_units self.m_size = ( network_settings.memory.memory_size if network_settings.memory is not None else 0 ) self.action_spec = action_spec self.observation_encoder = ObservationEncoder( observation_specs, self.h_size, network_settings.vis_encode_type, self.normalize, ) self.processors = self.observation_encoder.processors # Modules for multi-agent self-attention obs_only_ent_size = self.observation_encoder.total_enc_size q_ent_size = ( obs_only_ent_size + sum(self.action_spec.discrete_branches) + self.action_spec.continuous_size ) self.obs_encoder = EntityEmbedding(obs_only_ent_size, None, self.h_size) self.obs_action_encoder = EntityEmbedding(q_ent_size, None, self.h_size) self.self_attn = ResidualSelfAttention(self.h_size) self.linear_encoder = LinearEncoder( self.h_size, network_settings.num_layers, self.h_size, kernel_gain=(0.125 / self.h_size) ** 0.5, ) if self.use_lstm: self.lstm = LSTM(self.h_size, self.m_size) else: self.lstm = None # type: ignore @property def memory_size(self) -> int: return self.lstm.memory_size if self.use_lstm else 0 def update_normalization(self, buffer: AgentBuffer) -> None: self.observation_encoder.update_normalization(buffer) def copy_normalization(self, other_network: "MultiAgentNetworkBody") -> None: self.observation_encoder.copy_normalization(other_network.observation_encoder) def _get_masks_from_nans(self, obs_tensors: List[torch.Tensor]) -> torch.Tensor: """ Get attention masks by grabbing an arbitrary obs across all the agents Since these are raw obs, the padded values are still NaN """ only_first_obs = [_all_obs[0] for _all_obs in obs_tensors] # Just get the first element in each obs regardless of its dimension. This will speed up # searching for NaNs. only_first_obs_flat = torch.stack( [_obs.flatten(start_dim=1)[:, 0] for _obs in only_first_obs], dim=1 ) # Get the mask from NaNs attn_mask = only_first_obs_flat.isnan().float() return attn_mask def _copy_and_remove_nans_from_obs( self, all_obs: List[List[torch.Tensor]], attention_mask: torch.Tensor ) -> List[List[torch.Tensor]]: """ Helper function to remove NaNs from observations using an attention mask. """ obs_with_no_nans = [] for i_agent, single_agent_obs in enumerate(all_obs): no_nan_obs = [] for obs in single_agent_obs: new_obs = obs.clone() new_obs[ attention_mask.bool()[:, i_agent], :: ] = 0.0 # Remoove NaNs fast no_nan_obs.append(new_obs) obs_with_no_nans.append(no_nan_obs) return obs_with_no_nans def forward( self, obs_only: List[List[torch.Tensor]], obs: List[List[torch.Tensor]], actions: List[AgentAction], memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[torch.Tensor, torch.Tensor]: """ Returns sampled actions. If memory is enabled, return the memories as well. :param obs_only: Observations to be processed that do not have corresponding actions. These are encoded with the obs_encoder. :param obs: Observations to be processed that do have corresponding actions. After concatenation with actions, these are processed with obs_action_encoder. :param actions: After concatenation with obs, these are processed with obs_action_encoder. :param memories: If using memory, a Tensor of initial memories. :param sequence_length: If using memory, the sequence length. """ self_attn_masks = [] self_attn_inputs = [] concat_f_inp = [] if obs: obs_attn_mask = self._get_masks_from_nans(obs) obs = self._copy_and_remove_nans_from_obs(obs, obs_attn_mask) for inputs, action in zip(obs, actions): encoded = self.observation_encoder(inputs) cat_encodes = [ encoded, action.to_flat(self.action_spec.discrete_branches), ] concat_f_inp.append(torch.cat(cat_encodes, dim=1)) f_inp = torch.stack(concat_f_inp, dim=1) self_attn_masks.append(obs_attn_mask) self_attn_inputs.append(self.obs_action_encoder(None, f_inp)) concat_encoded_obs = [] if obs_only: obs_only_attn_mask = self._get_masks_from_nans(obs_only) obs_only = self._copy_and_remove_nans_from_obs(obs_only, obs_only_attn_mask) for inputs in obs_only: encoded = self.observation_encoder(inputs) concat_encoded_obs.append(encoded) g_inp = torch.stack(concat_encoded_obs, dim=1) self_attn_masks.append(obs_only_attn_mask) self_attn_inputs.append(self.obs_encoder(None, g_inp)) encoded_entity = torch.cat(self_attn_inputs, dim=1) encoded_state = self.self_attn(encoded_entity, self_attn_masks) encoding = self.linear_encoder(encoded_state) if self.use_lstm: # Resize to (batch, sequence length, encoding size) encoding = encoding.reshape([-1, sequence_length, self.h_size]) encoding, memories = self.lstm(encoding, memories) encoding = encoding.reshape([-1, self.m_size // 2]) return encoding, memories class Critic(abc.ABC): @abc.abstractmethod def update_normalization(self, buffer: AgentBuffer) -> None: """ Updates normalization of Actor based on the provided List of vector obs. :param vector_obs: A List of vector obs as tensors. """ pass def critic_pass( self, inputs: List[torch.Tensor], memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[Dict[str, torch.Tensor], torch.Tensor]: """ Get value outputs for the given obs. :param inputs: List of inputs as tensors. :param memories: Tensor of memories, if using memory. Otherwise, None. :returns: Dict of reward stream to output tensor for values. """ pass class ValueNetwork(nn.Module, Critic): def __init__( self, stream_names: List[str], observation_specs: List[ObservationSpec], network_settings: NetworkSettings, encoded_act_size: int = 0, outputs_per_stream: int = 1, ): # This is not a typo, we want to call __init__ of nn.Module nn.Module.__init__(self) self.network_body = NetworkBody( observation_specs, network_settings, encoded_act_size=encoded_act_size ) if network_settings.memory is not None: encoding_size = network_settings.memory.memory_size // 2 else: encoding_size = network_settings.hidden_units self.value_heads = ValueHeads(stream_names, encoding_size, outputs_per_stream) def update_normalization(self, buffer: AgentBuffer) -> None: self.network_body.update_normalization(buffer) @property def memory_size(self) -> int: return self.network_body.memory_size def critic_pass( self, inputs: List[torch.Tensor], memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[Dict[str, torch.Tensor], torch.Tensor]: value_outputs, critic_mem_out = self.forward( inputs, memories=memories, sequence_length=sequence_length ) return value_outputs, critic_mem_out def forward( self, inputs: List[torch.Tensor], actions: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[Dict[str, torch.Tensor], torch.Tensor]: encoding, memories = self.network_body( inputs, actions, memories, sequence_length ) output = self.value_heads(encoding) return output, memories class Actor(abc.ABC): @abc.abstractmethod def update_normalization(self, buffer: AgentBuffer) -> None: """ Updates normalization of Actor based on the provided List of vector obs. :param vector_obs: A List of vector obs as tensors. """ pass def get_action_and_stats( self, inputs: List[torch.Tensor], masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[AgentAction, ActionLogProbs, torch.Tensor, torch.Tensor]: """ Returns sampled actions. If memory is enabled, return the memories as well. :param inputs: A List of inputs as tensors. :param masks: If using discrete actions, a Tensor of action masks. :param memories: If using memory, a Tensor of initial memories. :param sequence_length: If using memory, the sequence length. :return: A Tuple of AgentAction, ActionLogProbs, entropies, and memories. Memories will be None if not using memory. """ pass def get_stats( self, inputs: List[torch.Tensor], actions: AgentAction, masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[ActionLogProbs, torch.Tensor]: """ Returns log_probs for actions and entropies. If memory is enabled, return the memories as well. :param inputs: A List of inputs as tensors. :param actions: AgentAction of actions. :param masks: If using discrete actions, a Tensor of action masks. :param memories: If using memory, a Tensor of initial memories. :param sequence_length: If using memory, the sequence length. :return: A Tuple of AgentAction, ActionLogProbs, entropies, and memories. Memories will be None if not using memory. """ pass @abc.abstractmethod def forward( self, inputs: List[torch.Tensor], masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, ) -> Tuple[Union[int, torch.Tensor], ...]: """ Forward pass of the Actor for inference. This is required for export to ONNX, and the inputs and outputs of this method should not be changed without a respective change in the ONNX export code. """ pass class SimpleActor(nn.Module, Actor): MODEL_EXPORT_VERSION = 3 # Corresponds to ModelApiVersion.MLAgents2_0 def __init__( self, observation_specs: List[ObservationSpec], network_settings: NetworkSettings, action_spec: ActionSpec, conditional_sigma: bool = False, tanh_squash: bool = False, ): super().__init__() self.action_spec = action_spec self.version_number = torch.nn.Parameter( torch.Tensor([self.MODEL_EXPORT_VERSION]), requires_grad=False ) self.is_continuous_int_deprecated = torch.nn.Parameter( torch.Tensor([int(self.action_spec.is_continuous())]), requires_grad=False ) self.continuous_act_size_vector = torch.nn.Parameter( torch.Tensor([int(self.action_spec.continuous_size)]), requires_grad=False ) self.discrete_act_size_vector = torch.nn.Parameter( torch.Tensor([self.action_spec.discrete_branches]), requires_grad=False ) self.act_size_vector_deprecated = torch.nn.Parameter( torch.Tensor( [ self.action_spec.continuous_size + sum(self.action_spec.discrete_branches) ] ), requires_grad=False, ) self.network_body = NetworkBody(observation_specs, network_settings) if network_settings.memory is not None: self.encoding_size = network_settings.memory.memory_size // 2 else: self.encoding_size = network_settings.hidden_units self.memory_size_vector = torch.nn.Parameter( torch.Tensor([int(self.network_body.memory_size)]), requires_grad=False ) self.action_model = ActionModel( self.encoding_size, action_spec, conditional_sigma=conditional_sigma, tanh_squash=tanh_squash, ) @property def memory_size(self) -> int: return self.network_body.memory_size def update_normalization(self, buffer: AgentBuffer) -> None: self.network_body.update_normalization(buffer) def get_action_and_stats( self, inputs: List[torch.Tensor], masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[AgentAction, ActionLogProbs, torch.Tensor, torch.Tensor]: encoding, memories = self.network_body( inputs, memories=memories, sequence_length=sequence_length ) action, log_probs, entropies = self.action_model(encoding, masks) return action, log_probs, entropies, memories def get_stats( self, inputs: List[torch.Tensor], actions: AgentAction, masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[ActionLogProbs, torch.Tensor]: encoding, actor_mem_outs = self.network_body( inputs, memories=memories, sequence_length=sequence_length ) log_probs, entropies = self.action_model.evaluate(encoding, masks, actions) return log_probs, entropies def forward( self, inputs: List[torch.Tensor], masks: Optional[torch.Tensor] = None, memories: Optional[torch.Tensor] = None, ) -> Tuple[Union[int, torch.Tensor], ...]: """ Note: This forward() method is required for exporting to ONNX. Don't modify the inputs and outputs. At this moment, torch.onnx.export() doesn't accept None as tensor to be exported, so the size of return tuple varies with action spec. """ encoding, memories_out = self.network_body( inputs, memories=memories, sequence_length=1 ) ( cont_action_out, disc_action_out, action_out_deprecated, ) = self.action_model.get_action_out(encoding, masks) export_out = [self.version_number, self.memory_size_vector] if self.action_spec.continuous_size > 0: export_out += [cont_action_out, self.continuous_act_size_vector] if self.action_spec.discrete_size > 0: export_out += [disc_action_out, self.discrete_act_size_vector] if self.network_body.memory_size > 0: export_out += [memories_out] return tuple(export_out) class SharedActorCritic(SimpleActor, Critic): def __init__( self, observation_specs: List[ObservationSpec], network_settings: NetworkSettings, action_spec: ActionSpec, stream_names: List[str], conditional_sigma: bool = False, tanh_squash: bool = False, ): self.use_lstm = network_settings.memory is not None super().__init__( observation_specs, network_settings, action_spec, conditional_sigma, tanh_squash, ) self.stream_names = stream_names self.value_heads = ValueHeads(stream_names, self.encoding_size) def critic_pass( self, inputs: List[torch.Tensor], memories: Optional[torch.Tensor] = None, sequence_length: int = 1, ) -> Tuple[Dict[str, torch.Tensor], torch.Tensor]: encoding, memories_out = self.network_body( inputs, memories=memories, sequence_length=sequence_length ) return self.value_heads(encoding), memories_out class GlobalSteps(nn.Module): def __init__(self): super().__init__() self.__global_step = nn.Parameter( torch.Tensor([0]).to(torch.int64), requires_grad=False ) @property def current_step(self): return int(self.__global_step.item()) @current_step.setter def current_step(self, value): self.__global_step[:] = value def increment(self, value): self.__global_step += value class LearningRate(nn.Module): def __init__(self, lr): # Todo: add learning rate decay super().__init__() self.learning_rate = torch.Tensor([lr])