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Source code for ding.model.template.q_learning

from typing import Union, Optional, Dict, Callable, List
import torch
import torch.nn as nn

from ding.torch_utils import get_lstm
from ding.utils import MODEL_REGISTRY, SequenceType, squeeze
from ..common import FCEncoder, ConvEncoder, DiscreteHead, DuelingHead, MultiHead, RainbowHead, \
    QuantileHead, FQFHead, QRDQNHead, DistributionHead, BranchingHead
from ding.torch_utils.network.gtrxl import GTrXL


[docs]@MODEL_REGISTRY.register('dqn') class DQN(nn.Module): """ Overview: The neural nework structure and computation graph of Deep Q Network (DQN) algorithm, which is the most classic \ value-based RL algorithm for discrete action. The DQN is composed of two parts: ``encoder`` and ``head``. \ The ``encoder`` is used to extract the feature from various observation, and the ``head`` is used to compute \ the Q value of each action dimension. Interfaces: ``__init__``, ``forward``. .. note:: Current ``DQN`` supports two types of encoder: ``FCEncoder`` and ``ConvEncoder``, two types of head: \ ``DiscreteHead`` and ``DuelingHead``. You can customize your own encoder or head by inheriting this class. """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], dueling: bool = True, head_hidden_size: Optional[int] = None, head_layer_num: int = 1, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None, dropout: Optional[float] = None, init_bias: Optional[float] = None, ) -> None: """ Overview: initialize the DQN (encoder + head) Model according to corresponding input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape, such as 8 or [4, 84, 84]. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape, such as 6 or [2, 3, 3]. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder``, \ the last element must match ``head_hidden_size``. - dueling (:obj:`Optional[bool]`): Whether choose ``DuelingHead`` or ``DiscreteHead (default)``. - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` of head network, defaults to None, \ then it will be set to the last element of ``encoder_hidden_size_list``. - head_layer_num (:obj:`int`): The number of layers used in the head network to compute Q value output. - activation (:obj:`Optional[nn.Module]`): The type of activation function in networks \ if ``None`` then default set it to ``nn.ReLU()``. - norm_type (:obj:`Optional[str]`): The type of normalization in networks, see \ ``ding.torch_utils.fc_block`` for more details. you can choose one of ['BN', 'IN', 'SyncBN', 'LN'] - dropout (:obj:`Optional[float]`): The dropout rate of the dropout layer. \ if ``None`` then default disable dropout layer. - init_bias (:obj:`Optional[float]`): The initial value of the last layer bias in the head network. \ """ super(DQN, self).__init__() # Squeeze data from tuple, list or dict to single object. For example, from (4, ) to 4 obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder( obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type, dropout=dropout ) # Conv Encoder elif len(obs_shape) == 3: assert dropout is None, "dropout is not supported in ConvEncoder" self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own DQN".format(obs_shape) ) # Head Type if dueling: head_cls = DuelingHead else: head_cls = DiscreteHead multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( head_cls, head_hidden_size, action_shape, layer_num=head_layer_num, activation=activation, norm_type=norm_type, dropout=dropout ) else: self.head = head_cls( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type, dropout=dropout ) if init_bias is not None and head_cls == DuelingHead: # Zero the last layer bias of advantage head self.head.A[-1][0].bias.data.fill_(init_bias)
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: DQN forward computation graph, input observation tensor to predict q_value. Arguments: - x (:obj:`torch.Tensor`): The input observation tensor data. Returns: - outputs (:obj:`Dict`): The output of DQN's forward, including q_value. ReturnsKeys: - logit (:obj:`torch.Tensor`): Discrete Q-value output of each possible action dimension. Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is ``obs_shape`` - logit (:obj:`torch.Tensor`): :math:`(B, M)`, where B is batch size and M is ``action_shape`` Examples: >>> model = DQN(32, 6) # arguments: 'obs_shape' and 'action_shape' >>> inputs = torch.randn(4, 32) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) and outputs['logit'].shape == torch.Size([4, 6]) .. note:: For consistency and compatibility, we name all the outputs of the network which are related to action \ selections as ``logit``. """ x = self.encoder(x) x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('bdq') class BDQ(nn.Module):
[docs] def __init__( self, obs_shape: Union[int, SequenceType], num_branches: int = 0, action_bins_per_branch: int = 2, layer_num: int = 3, a_layer_num: Optional[int] = None, v_layer_num: Optional[int] = None, encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: Optional[int] = None, norm_type: Optional[nn.Module] = None, activation: Optional[nn.Module] = nn.ReLU(), ) -> None: """ Overview: Init the BDQ (encoder + head) Model according to input arguments. \ referenced paper Action Branching Architectures for Deep Reinforcement Learning \ <https://arxiv.org/pdf/1711.08946> Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape, such as 8 or [4, 84, 84]. - num_branches (:obj:`int`): The number of branches, which is equivalent to the action dimension, \ such as 6 in mujoco's halfcheetah environment. - action_bins_per_branch (:obj:`int`): The number of actions in each dimension. - layer_num (:obj:`int`): The number of layers used in the network to compute Advantage and Value output. - a_layer_num (:obj:`int`): The number of layers used in the network to compute Advantage output. - v_layer_num (:obj:`int`): The number of layers used in the network to compute Value output. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder``, \ the last element must match ``head_hidden_size``. - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` of head network. - norm_type (:obj:`Optional[str]`): The type of normalization in networks, see \ ``ding.torch_utils.fc_block`` for more details. - activation (:obj:`Optional[nn.Module]`): The type of activation function in networks \ if ``None`` then default set it to ``nn.ReLU()`` """ super(BDQ, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, num_branches = squeeze(obs_shape), squeeze(num_branches) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # backbone # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own DQN".format(obs_shape) ) self.num_branches = num_branches self.action_bins_per_branch = action_bins_per_branch # head self.head = BranchingHead( head_hidden_size, num_branches=self.num_branches, action_bins_per_branch=self.action_bins_per_branch, layer_num=layer_num, a_layer_num=a_layer_num, v_layer_num=v_layer_num, activation=activation, norm_type=norm_type )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: BDQ forward computation graph, input observation tensor to predict q_value. Arguments: - x (:obj:`torch.Tensor`): Observation inputs Returns: - outputs (:obj:`Dict`): BDQ forward outputs, such as q_value. ReturnsKeys: - logit (:obj:`torch.Tensor`): Discrete Q-value output of each action dimension. Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is ``obs_shape`` - logit (:obj:`torch.FloatTensor`): :math:`(B, M)`, where B is batch size and M is ``num_branches * action_bins_per_branch`` Examples: >>> model = BDQ(8, 5, 2) # arguments: 'obs_shape', 'num_branches' and 'action_bins_per_branch'. >>> inputs = torch.randn(4, 8) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) and outputs['logit'].shape == torch.Size([4, 5, 2]) """ x = self.encoder(x) / (self.num_branches + 1) # corresponds to the "Gradient Rescaling" in the paper x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('c51dqn') class C51DQN(nn.Module): """ Overview: The neural network structure and computation graph of C51DQN, which combines distributional RL and DQN. \ You can refer to https://arxiv.org/pdf/1707.06887.pdf for more details. The C51DQN is composed of \ ``encoder`` and ``head``. ``encoder`` is used to extract the feature of observation, and ``head`` is \ used to compute the distribution of Q-value. Interfaces: ``__init__``, ``forward`` .. note:: Current C51DQN supports two types of encoder: ``FCEncoder`` and ``ConvEncoder``. """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: int = None, head_layer_num: int = 1, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None, v_min: Optional[float] = -10, v_max: Optional[float] = 10, n_atom: Optional[int] = 51, ) -> None: """ Overview: initialize the C51 Model according to corresponding input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape, such as 8 or [4, 84, 84]. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape, such as 6 or [2, 3, 3]. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder``, \ the last element must match ``head_hidden_size``. - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` of head network, defaults to None, \ then it will be set to the last element of ``encoder_hidden_size_list``. - head_layer_num (:obj:`int`): The number of layers used in the head network to compute Q value output. - activation (:obj:`Optional[nn.Module]`): The type of activation function in networks \ if ``None`` then default set it to ``nn.ReLU()``. - norm_type (:obj:`Optional[str]`): The type of normalization in networks, see \ ``ding.torch_utils.fc_block`` for more details. you can choose one of ['BN', 'IN', 'SyncBN', 'LN'] - v_min (:obj:`Optional[float]`): The minimum value of the support of the distribution, which is related \ to the value (discounted sum of reward) scale of the specific environment. Defaults to -10. - v_max (:obj:`Optional[float]`): The maximum value of the support of the distribution, which is related \ to the value (discounted sum of reward) scale of the specific environment. Defaults to 10. - n_atom (:obj:`Optional[int]`): The number of atoms in the prediction distribution, 51 is the default \ value in the paper, you can also try other values such as 301. """ super(C51DQN, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own C51DQN".format(obs_shape) ) # Head Type multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( DistributionHead, head_hidden_size, action_shape, layer_num=head_layer_num, activation=activation, norm_type=norm_type, n_atom=n_atom, v_min=v_min, v_max=v_max, ) else: self.head = DistributionHead( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type, n_atom=n_atom, v_min=v_min, v_max=v_max, )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: C51DQN forward computation graph, input observation tensor to predict q_value and its distribution. Arguments: - x (:obj:`torch.Tensor`): The input observation tensor data. Returns: - outputs (:obj:`Dict`): The output of DQN's forward, including q_value, and distribution. ReturnsKeys: - logit (:obj:`torch.Tensor`): Discrete Q-value output of each possible action dimension. - distribution (:obj:`torch.Tensor`): Q-Value discretized distribution, i.e., probability of each \ uniformly spaced atom Q-value, such as dividing [-10, 10] into 51 uniform spaces. Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is head_hidden_size. - logit (:obj:`torch.Tensor`): :math:`(B, M)`, where M is action_shape. - distribution(:obj:`torch.Tensor`): :math:`(B, M, P)`, where P is n_atom. Examples: >>> model = C51DQN(128, 64) # arguments: 'obs_shape' and 'action_shape' >>> inputs = torch.randn(4, 128) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) >>> # default head_hidden_size: int = 64, >>> assert outputs['logit'].shape == torch.Size([4, 64]) >>> # default n_atom: int = 51 >>> assert outputs['distribution'].shape == torch.Size([4, 64, 51]) .. note:: For consistency and compatibility, we name all the outputs of the network which are related to action \ selections as ``logit``. .. note:: For convenience, we recommend that the number of atoms should be odd, so that the middle atom is exactly \ the value of the Q-value. """ x = self.encoder(x) x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('qrdqn') class QRDQN(nn.Module): """ Overview: The neural network structure and computation graph of QRDQN, which combines distributional RL and DQN. \ You can refer to Distributional Reinforcement Learning with Quantile Regression \ https://arxiv.org/pdf/1710.10044.pdf for more details. Interfaces: ``__init__``, ``forward`` """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: Optional[int] = None, head_layer_num: int = 1, num_quantiles: int = 32, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None, ) -> None: """ Overview: Initialize the QRDQN Model according to input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation's space. - action_shape (:obj:`Union[int, SequenceType]`): Action's space. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder`` - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` to pass to ``Head``. - head_layer_num (:obj:`int`): The num of layers used in the network to compute Q value output - num_quantiles (:obj:`int`): Number of quantiles in the prediction distribution. - activation (:obj:`Optional[nn.Module]`): The type of activation function to use in ``MLP`` the after ``layer_fn``, if ``None`` then default set to ``nn.ReLU()`` - norm_type (:obj:`Optional[str]`): The type of normalization to use, see ``ding.torch_utils.fc_block`` for more details` """ super(QRDQN, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own QRDQN".format(obs_shape) ) # Head Type multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( QRDQNHead, head_hidden_size, action_shape, layer_num=head_layer_num, num_quantiles=num_quantiles, activation=activation, norm_type=norm_type, ) else: self.head = QRDQNHead( head_hidden_size, action_shape, head_layer_num, num_quantiles=num_quantiles, activation=activation, norm_type=norm_type, )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: Use observation tensor to predict QRDQN's output. Parameter updates with QRDQN's MLPs forward setup. Arguments: - x (:obj:`torch.Tensor`): The encoded embedding tensor with ``(B, N=hidden_size)``. Returns: - outputs (:obj:`Dict`): Run with encoder and head. Return the result prediction dictionary. ReturnsKeys: - logit (:obj:`torch.Tensor`): Logit tensor with same size as input ``x``. - q (:obj:`torch.Tensor`): Q valye tensor tensor of size ``(B, N, num_quantiles)`` - tau (:obj:`torch.Tensor`): tau tensor of size ``(B, N, 1)`` Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is head_hidden_size. - logit (:obj:`torch.FloatTensor`): :math:`(B, M)`, where M is action_shape. - tau (:obj:`torch.Tensor`): :math:`(B, M, 1)` Examples: >>> model = QRDQN(64, 64) >>> inputs = torch.randn(4, 64) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) >>> assert outputs['logit'].shape == torch.Size([4, 64]) >>> # default num_quantiles : int = 32 >>> assert outputs['q'].shape == torch.Size([4, 64, 32]) >>> assert outputs['tau'].shape == torch.Size([4, 32, 1]) """ x = self.encoder(x) x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('iqn') class IQN(nn.Module): """ Overview: The neural network structure and computation graph of IQN, which combines distributional RL and DQN. \ You can refer to paper Implicit Quantile Networks for Distributional Reinforcement Learning \ https://arxiv.org/pdf/1806.06923.pdf for more details. Interfaces: ``__init__``, ``forward`` """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: Optional[int] = None, head_layer_num: int = 1, num_quantiles: int = 32, quantile_embedding_size: int = 128, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None ) -> None: """ Overview: Initialize the IQN Model according to input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder`` - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` to pass to ``Head``. - head_layer_num (:obj:`int`): The num of layers used in the network to compute Q value output - num_quantiles (:obj:`int`): Number of quantiles in the prediction distribution. - activation (:obj:`Optional[nn.Module]`): The type of activation function to use in ``MLP`` the after ``layer_fn``, if ``None`` then default set to ``nn.ReLU()`` - norm_type (:obj:`Optional[str]`): The type of normalization to use, see ``ding.torch_utils.fc_block`` for more details. """ super(IQN, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own IQN".format(obs_shape) ) # Head Type head_cls = QuantileHead multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( head_cls, head_hidden_size, action_shape, layer_num=head_layer_num, num_quantiles=num_quantiles, quantile_embedding_size=quantile_embedding_size, activation=activation, norm_type=norm_type ) else: self.head = head_cls( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type, num_quantiles=num_quantiles, quantile_embedding_size=quantile_embedding_size, )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: Use encoded embedding tensor to predict IQN's output. Parameter updates with IQN's MLPs forward setup. Arguments: - x (:obj:`torch.Tensor`): The encoded embedding tensor with ``(B, N=hidden_size)``. Returns: - outputs (:obj:`Dict`): Run with encoder and head. Return the result prediction dictionary. ReturnsKeys: - logit (:obj:`torch.Tensor`): Logit tensor with same size as input ``x``. - q (:obj:`torch.Tensor`): Q valye tensor tensor of size ``(num_quantiles, N, B)`` - quantiles (:obj:`torch.Tensor`): quantiles tensor of size ``(quantile_embedding_size, 1)`` Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is head_hidden_size. - logit (:obj:`torch.FloatTensor`): :math:`(B, M)`, where M is action_shape - quantiles (:obj:`torch.Tensor`): :math:`(P, 1)`, where P is quantile_embedding_size. Examples: >>> model = IQN(64, 64) # arguments: 'obs_shape' and 'action_shape' >>> inputs = torch.randn(4, 64) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) >>> assert outputs['logit'].shape == torch.Size([4, 64]) >>> # default num_quantiles: int = 32 >>> assert outputs['q'].shape == torch.Size([32, 4, 64] >>> # default quantile_embedding_size: int = 128 >>> assert outputs['quantiles'].shape == torch.Size([128, 1]) """ x = self.encoder(x) x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('fqf') class FQF(nn.Module): """ Overview: The neural network structure and computation graph of FQF, which combines distributional RL and DQN. \ You can refer to paper Fully Parameterized Quantile Function for Distributional Reinforcement Learning \ https://arxiv.org/pdf/1911.02140.pdf for more details. Interface: ``__init__``, ``forward`` """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: Optional[int] = None, head_layer_num: int = 1, num_quantiles: int = 32, quantile_embedding_size: int = 128, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None ) -> None: """ Overview: Initialize the FQF Model according to input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder`` - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` to pass to ``Head``. - head_layer_num (:obj:`int`): The num of layers used in the network to compute Q value output - num_quantiles (:obj:`int`): Number of quantiles in the prediction distribution. - activation (:obj:`Optional[nn.Module]`): The type of activation function to use in ``MLP`` the after ``layer_fn``, if ``None`` then default set to ``nn.ReLU()`` - norm_type (:obj:`Optional[str]`): The type of normalization to use, see ``ding.torch_utils.fc_block`` for more details. """ super(FQF, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own FQF".format(obs_shape) ) # Head Type head_cls = FQFHead multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( head_cls, head_hidden_size, action_shape, layer_num=head_layer_num, num_quantiles=num_quantiles, quantile_embedding_size=quantile_embedding_size, activation=activation, norm_type=norm_type ) else: self.head = head_cls( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type, num_quantiles=num_quantiles, quantile_embedding_size=quantile_embedding_size, )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: Use encoded embedding tensor to predict FQF's output. Parameter updates with FQF's MLPs forward setup. Arguments: - x (:obj:`torch.Tensor`): The encoded embedding tensor with ``(B, N=hidden_size)``. Returns: - outputs (:obj:`Dict`): Dict containing keywords ``logit`` (:obj:`torch.Tensor`), \ ``q`` (:obj:`torch.Tensor`), ``quantiles`` (:obj:`torch.Tensor`), \ ``quantiles_hats`` (:obj:`torch.Tensor`), \ ``q_tau_i`` (:obj:`torch.Tensor`), ``entropies`` (:obj:`torch.Tensor`). Shapes: - x: :math:`(B, N)`, where B is batch size and N is head_hidden_size. - logit: :math:`(B, M)`, where M is action_shape. - q: :math:`(B, num_quantiles, M)`. - quantiles: :math:`(B, num_quantiles + 1)`. - quantiles_hats: :math:`(B, num_quantiles)`. - q_tau_i: :math:`(B, num_quantiles - 1, M)`. - entropies: :math:`(B, 1)`. Examples: >>> model = FQF(64, 64) # arguments: 'obs_shape' and 'action_shape' >>> inputs = torch.randn(4, 64) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) >>> assert outputs['logit'].shape == torch.Size([4, 64]) >>> # default num_quantiles: int = 32 >>> assert outputs['q'].shape == torch.Size([4, 32, 64]) >>> assert outputs['quantiles'].shape == torch.Size([4, 33]) >>> assert outputs['quantiles_hats'].shape == torch.Size([4, 32]) >>> assert outputs['q_tau_i'].shape == torch.Size([4, 31, 64]) >>> assert outputs['quantiles'].shape == torch.Size([4, 1]) """ x = self.encoder(x) x = self.head(x) return x
[docs]@MODEL_REGISTRY.register('rainbowdqn') class RainbowDQN(nn.Module): """ Overview: The neural network structure and computation graph of RainbowDQN, which combines distributional RL and DQN. \ You can refer to paper Rainbow: Combining Improvements in Deep Reinforcement Learning \ https://arxiv.org/pdf/1710.02298.pdf for more details. Interfaces: ``__init__``, ``forward`` .. note:: RainbowDQN contains dueling architecture by default. """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], head_hidden_size: Optional[int] = None, head_layer_num: int = 1, activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None, v_min: Optional[float] = -10, v_max: Optional[float] = 10, n_atom: Optional[int] = 51, ) -> None: """ Overview: Init the Rainbow Model according to arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder`` - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` to pass to ``Head``. - head_layer_num (:obj:`int`): The num of layers used in the network to compute Q value output - activation (:obj:`Optional[nn.Module]`): The type of activation function to use in ``MLP`` the after \ ``layer_fn``, if ``None`` then default set to ``nn.ReLU()`` - norm_type (:obj:`Optional[str]`): The type of normalization to use, see ``ding.torch_utils.fc_block`` \ for more details` - n_atom (:obj:`Optional[int]`): Number of atoms in the prediction distribution. """ super(RainbowDQN, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own RainbowDQN". format(obs_shape) ) # Head Type multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( RainbowHead, head_hidden_size, action_shape, layer_num=head_layer_num, activation=activation, norm_type=norm_type, n_atom=n_atom, v_min=v_min, v_max=v_max, ) else: self.head = RainbowHead( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type, n_atom=n_atom, v_min=v_min, v_max=v_max, )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: Use observation tensor to predict Rainbow output. Parameter updates with Rainbow's MLPs forward setup. Arguments: - x (:obj:`torch.Tensor`): The encoded embedding tensor with ``(B, N=hidden_size)``. Returns: - outputs (:obj:`Dict`): Run ``MLP`` with ``RainbowHead`` setups and return the result prediction dictionary. ReturnsKeys: - logit (:obj:`torch.Tensor`): Logit tensor with same size as input ``x``. - distribution (:obj:`torch.Tensor`): Distribution tensor of size ``(B, N, n_atom)`` Shapes: - x (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is head_hidden_size. - logit (:obj:`torch.FloatTensor`): :math:`(B, M)`, where M is action_shape. - distribution(:obj:`torch.FloatTensor`): :math:`(B, M, P)`, where P is n_atom. Examples: >>> model = RainbowDQN(64, 64) # arguments: 'obs_shape' and 'action_shape' >>> inputs = torch.randn(4, 64) >>> outputs = model(inputs) >>> assert isinstance(outputs, dict) >>> assert outputs['logit'].shape == torch.Size([4, 64]) >>> # default n_atom: int =51 >>> assert outputs['distribution'].shape == torch.Size([4, 64, 51]) """ x = self.encoder(x) x = self.head(x) return x
def parallel_wrapper(forward_fn: Callable) -> Callable: """ Overview: Process timestep T and batch_size B at the same time, in other words, treat different timestep data as different trajectories in a batch. Arguments: - forward_fn (:obj:`Callable`): Normal ``nn.Module`` 's forward function. Returns: - wrapper (:obj:`Callable`): Wrapped function. """ def wrapper(x: torch.Tensor) -> Union[torch.Tensor, List[torch.Tensor]]: T, B = x.shape[:2] def reshape(d): if isinstance(d, list): d = [reshape(t) for t in d] elif isinstance(d, dict): d = {k: reshape(v) for k, v in d.items()} else: d = d.reshape(T, B, *d.shape[1:]) return d # NOTE(rjy): the initial input shape will be (T, B, N), # means encoder or head should process B trajectorys, each trajectory has T timestep, # but T and B dimension can be both treated as batch_size in encoder and head, # i.e., independent and parallel processing, # so here we need such fn to reshape for encoder or head x = x.reshape(T * B, *x.shape[2:]) x = forward_fn(x) x = reshape(x) return x return wrapper
[docs]@MODEL_REGISTRY.register('drqn') class DRQN(nn.Module): """ Overview: The neural network structure and computation graph of DRQN (DQN + RNN = DRQN) algorithm, which is the most \ common DQN variant for sequential data and paratially observable environment. The DRQN is composed of three \ parts: ``encoder``, ``head`` and ``rnn``. The ``encoder`` is used to extract the feature from various \ observation, the ``rnn`` is used to process the sequential observation and other data, and the ``head`` is \ used to compute the Q value of each action dimension. Interfaces: ``__init__``, ``forward``. .. note:: Current ``DRQN`` supports two types of encoder: ``FCEncoder`` and ``ConvEncoder``, two types of head: \ ``DiscreteHead`` and ``DuelingHead``, three types of rnn: ``normal (LSTM with LayerNorm)``, ``pytorch`` and \ ``gru``. You can customize your own encoder, rnn or head by inheriting this class. """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], encoder_hidden_size_list: SequenceType = [128, 128, 64], dueling: bool = True, head_hidden_size: Optional[int] = None, head_layer_num: int = 1, lstm_type: Optional[str] = 'normal', activation: Optional[nn.Module] = nn.ReLU(), norm_type: Optional[str] = None, res_link: bool = False ) -> None: """ Overview: Initialize the DRQN Model according to the corresponding input arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Observation space shape, such as 8 or [4, 84, 84]. - action_shape (:obj:`Union[int, SequenceType]`): Action space shape, such as 6 or [2, 3, 3]. - encoder_hidden_size_list (:obj:`SequenceType`): Collection of ``hidden_size`` to pass to ``Encoder``, \ the last element must match ``head_hidden_size``. - dueling (:obj:`Optional[bool]`): Whether choose ``DuelingHead`` or ``DiscreteHead (default)``. - head_hidden_size (:obj:`Optional[int]`): The ``hidden_size`` of head network, defaults to None, \ then it will be set to the last element of ``encoder_hidden_size_list``. - head_layer_num (:obj:`int`): The number of layers used in the head network to compute Q value output. - lstm_type (:obj:`Optional[str]`): The type of RNN module, now support ['normal', 'pytorch', 'gru']. - activation (:obj:`Optional[nn.Module]`): The type of activation function in networks \ if ``None`` then default set it to ``nn.ReLU()``. - norm_type (:obj:`Optional[str]`): The type of normalization in networks, see \ ``ding.torch_utils.fc_block`` for more details. you can choose one of ['BN', 'IN', 'SyncBN', 'LN'] - res_link (:obj:`bool`): Whether to enable the residual link, which is the skip connnection between \ single frame data and the sequential data, defaults to False. """ super(DRQN, self).__init__() # For compatibility: 1, (1, ), [4, 32, 32] obs_shape, action_shape = squeeze(obs_shape), squeeze(action_shape) if head_hidden_size is None: head_hidden_size = encoder_hidden_size_list[-1] # FC Encoder if isinstance(obs_shape, int) or len(obs_shape) == 1: self.encoder = FCEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) # Conv Encoder elif len(obs_shape) == 3: self.encoder = ConvEncoder(obs_shape, encoder_hidden_size_list, activation=activation, norm_type=norm_type) else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own DRQN".format(obs_shape) ) # LSTM Type self.rnn = get_lstm(lstm_type, input_size=head_hidden_size, hidden_size=head_hidden_size) self.res_link = res_link # Head Type if dueling: head_cls = DuelingHead else: head_cls = DiscreteHead multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( head_cls, head_hidden_size, action_shape, layer_num=head_layer_num, activation=activation, norm_type=norm_type ) else: self.head = head_cls( head_hidden_size, action_shape, head_layer_num, activation=activation, norm_type=norm_type )
[docs] def forward(self, inputs: Dict, inference: bool = False, saved_state_timesteps: Optional[list] = None) -> Dict: """ Overview: DRQN forward computation graph, input observation tensor to predict q_value. Arguments: - inputs (:obj:`torch.Tensor`): The dict of input data, including observation and previous rnn state. - inference: (:obj:'bool'): Whether to enable inference forward mode, if True, we unroll the one timestep \ transition, otherwise, we unroll the eentire sequence transitions. - saved_state_timesteps: (:obj:'Optional[list]'): When inference is False, we unroll the sequence \ transitions, then we would use this list to indicate how to save and return hidden state. ArgumentsKeys: - obs (:obj:`torch.Tensor`): The raw observation tensor. - prev_state (:obj:`list`): The previous rnn state tensor, whose structure depends on ``lstm_type``. Returns: - outputs (:obj:`Dict`): The output of DRQN's forward, including logit (q_value) and next state. ReturnsKeys: - logit (:obj:`torch.Tensor`): Discrete Q-value output of each possible action dimension. - next_state (:obj:`list`): The next rnn state tensor, whose structure depends on ``lstm_type``. Shapes: - obs (:obj:`torch.Tensor`): :math:`(B, N)`, where B is batch size and N is ``obs_shape`` - logit (:obj:`torch.Tensor`): :math:`(B, M)`, where B is batch size and M is ``action_shape`` Examples: >>> # Init input's Keys: >>> prev_state = [[torch.randn(1, 1, 64) for __ in range(2)] for _ in range(4)] # B=4 >>> obs = torch.randn(4,64) >>> model = DRQN(64, 64) # arguments: 'obs_shape' and 'action_shape' >>> outputs = model({'obs': inputs, 'prev_state': prev_state}, inference=True) >>> # Check outputs's Keys >>> assert isinstance(outputs, dict) >>> assert outputs['logit'].shape == (4, 64) >>> assert len(outputs['next_state']) == 4 >>> assert all([len(t) == 2 for t in outputs['next_state']]) >>> assert all([t[0].shape == (1, 1, 64) for t in outputs['next_state']]) """ x, prev_state = inputs['obs'], inputs['prev_state'] # for both inference and other cases, the network structure is encoder -> rnn network -> head # the difference is inference take the data with seq_len=1 (or T = 1) # NOTE(rjy): in most situations, set inference=True when evaluate and inference=False when training if inference: x = self.encoder(x) if self.res_link: a = x x = x.unsqueeze(0) # for rnn input, put the seq_len of x as 1 instead of none. # prev_state: DataType: List[Tuple[torch.Tensor]]; Initially, it is a list of None x, next_state = self.rnn(x, prev_state) x = x.squeeze(0) # to delete the seq_len dim to match head network input if self.res_link: x = x + a x = self.head(x) x['next_state'] = next_state return x else: # In order to better explain why rnn needs saved_state and which states need to be stored, # let's take r2d2 as an example # in r2d2, # 1) data['burnin_nstep_obs'] = data['obs'][:bs + self._nstep] # 2) data['main_obs'] = data['obs'][bs:-self._nstep] # 3) data['target_obs'] = data['obs'][bs + self._nstep:] # NOTE(rjy): (T, B, N) or (T, B, C, H, W) assert len(x.shape) in [3, 5], x.shape x = parallel_wrapper(self.encoder)(x) # (T, B, N) if self.res_link: a = x # NOTE(rjy) lstm_embedding stores all hidden_state lstm_embedding = [] # TODO(nyz) how to deal with hidden_size key-value hidden_state_list = [] if saved_state_timesteps is not None: saved_state = [] for t in range(x.shape[0]): # T timesteps # NOTE(rjy) use x[t:t+1] but not x[t] can keep original dimension output, prev_state = self.rnn(x[t:t + 1], prev_state) # output: (1,B, head_hidden_size) if saved_state_timesteps is not None and t + 1 in saved_state_timesteps: saved_state.append(prev_state) lstm_embedding.append(output) hidden_state = [p['h'] for p in prev_state] # only keep ht, {list: x.shape[0]{Tensor:(1, batch_size, head_hidden_size)}} hidden_state_list.append(torch.cat(hidden_state, dim=1)) x = torch.cat(lstm_embedding, 0) # (T, B, head_hidden_size) if self.res_link: x = x + a x = parallel_wrapper(self.head)(x) # (T, B, action_shape) # NOTE(rjy): x['next_state'] is the hidden state of the last timestep inputted to lstm # the last timestep state including the hidden state (h) and the cell state (c) # shape: {list: B{dict: 2{Tensor:(1, 1, head_hidden_size}}} x['next_state'] = prev_state # all hidden state h, this returns a tensor of the dim: seq_len*batch_size*head_hidden_size # This key is used in qtran, the algorithm requires to retain all h_{t} during training x['hidden_state'] = torch.cat(hidden_state_list, dim=0) if saved_state_timesteps is not None: # the selected saved hidden states, including the hidden state (h) and the cell state (c) # in r2d2, set 'saved_hidden_state_timesteps=[self._burnin_step, self._burnin_step + self._nstep]', # then saved_state will record the hidden_state for main_obs and target_obs to # initialize their lstm (h c) x['saved_state'] = saved_state return x
[docs]@MODEL_REGISTRY.register('gtrxldqn') class GTrXLDQN(nn.Module): """ Overview: The neural network structure and computation graph of Gated Transformer-XL DQN algorithm, which is the \ enhanced version of DRQN, using Transformer-XL to improve long-term sequential modelling ability. The \ GTrXL-DQN is composed of three parts: ``encoder``, ``head`` and ``core``. The ``encoder`` is used to extract \ the feature from various observation, the ``core`` is used to process the sequential observation and other \ data, and the ``head`` is used to compute the Q value of each action dimension. Interfaces: ``__init__``, ``forward``, ``reset_memory``, ``get_memory`` . """
[docs] def __init__( self, obs_shape: Union[int, SequenceType], action_shape: Union[int, SequenceType], head_layer_num: int = 1, att_head_dim: int = 16, hidden_size: int = 16, att_head_num: int = 2, att_mlp_num: int = 2, att_layer_num: int = 3, memory_len: int = 64, activation: Optional[nn.Module] = nn.ReLU(), head_norm_type: Optional[str] = None, dropout: float = 0., gru_gating: bool = True, gru_bias: float = 2., dueling: bool = True, encoder_hidden_size_list: SequenceType = [128, 128, 256], encoder_norm_type: Optional[str] = None, ) -> None: """ Overview: Initialize the GTrXLDQN model accoding to corresponding input arguments. .. tip:: You can refer to GTrXl class in ``ding.torch_utils.network.gtrxl`` for more details about the input \ arguments. Arguments: - obs_shape (:obj:`Union[int, SequenceType]`): Used by Transformer. Observation's space. - action_shape (:obj:Union[int, SequenceType]): Used by Head. Action's space. - head_layer_num (:obj:`int`): Used by Head. Number of layers. - att_head_dim (:obj:`int`): Used by Transformer. - hidden_size (:obj:`int`): Used by Transformer and Head. - att_head_num (:obj:`int`): Used by Transformer. - att_mlp_num (:obj:`int`): Used by Transformer. - att_layer_num (:obj:`int`): Used by Transformer. - memory_len (:obj:`int`): Used by Transformer. - activation (:obj:`Optional[nn.Module]`): Used by Transformer and Head. if ``None`` then default set to \ ``nn.ReLU()``. - head_norm_type (:obj:`Optional[str]`): Used by Head. The type of normalization to use, see \ ``ding.torch_utils.fc_block`` for more details`. - dropout (:obj:`bool`): Used by Transformer. - gru_gating (:obj:`bool`): Used by Transformer. - gru_bias (:obj:`float`): Used by Transformer. - dueling (:obj:`bool`): Used by Head. Make the head dueling. - encoder_hidden_size_list(:obj:`SequenceType`): Used by Encoder. The collection of ``hidden_size`` if \ using a custom convolutional encoder. - encoder_norm_type (:obj:`Optional[str]`): Used by Encoder. The type of normalization to use, see \ ``ding.torch_utils.fc_block`` for more details`. """ super(GTrXLDQN, self).__init__() self.core = GTrXL( input_dim=obs_shape, head_dim=att_head_dim, embedding_dim=hidden_size, head_num=att_head_num, mlp_num=att_mlp_num, layer_num=att_layer_num, memory_len=memory_len, activation=activation, dropout_ratio=dropout, gru_gating=gru_gating, gru_bias=gru_bias, ) # for vector obs, use Identity Encoder, i.e. pass if isinstance(obs_shape, int) or len(obs_shape) == 1: pass # replace the embedding layer of Transformer with Conv Encoder elif len(obs_shape) == 3: assert encoder_hidden_size_list[-1] == hidden_size self.obs_encoder = ConvEncoder( obs_shape, encoder_hidden_size_list, activation=activation, norm_type=encoder_norm_type ) self.dropout = nn.Dropout(dropout) self.core.use_embedding_layer = False else: raise RuntimeError( "not support obs_shape for pre-defined encoder: {}, please customize your own GTrXL".format(obs_shape) ) # Head Type if dueling: head_cls = DuelingHead else: head_cls = DiscreteHead multi_head = not isinstance(action_shape, int) if multi_head: self.head = MultiHead( head_cls, hidden_size, action_shape, layer_num=head_layer_num, activation=activation, norm_type=head_norm_type ) else: self.head = head_cls( hidden_size, action_shape, head_layer_num, activation=activation, norm_type=head_norm_type )
[docs] def forward(self, x: torch.Tensor) -> Dict: """ Overview: Let input tensor go through GTrXl and the Head sequentially. Arguments: - x (:obj:`torch.Tensor`): input tensor of shape (seq_len, bs, obs_shape). Returns: - out (:obj:`Dict`): run ``GTrXL`` with ``DiscreteHead`` setups and return the result prediction dictionary. ReturnKeys: - logit (:obj:`torch.Tensor`): discrete Q-value output of each action dimension, shape is (B, action_space). - memory (:obj:`torch.Tensor`): memory tensor of size ``(bs x layer_num+1 x memory_len x embedding_dim)``. - transformer_out (:obj:`torch.Tensor`): output tensor of transformer with same size as input ``x``. Examples: >>> # Init input's Keys: >>> obs_dim, seq_len, bs, action_dim = 128, 64, 32, 4 >>> obs = torch.rand(seq_len, bs, obs_dim) >>> model = GTrXLDQN(obs_dim, action_dim) >>> outputs = model(obs) >>> assert isinstance(outputs, dict) """ if len(x.shape) == 5: # 3d obs: cur_seq, bs, ch, h, w x_ = x.reshape([x.shape[0] * x.shape[1]] + list(x.shape[-3:])) x_ = self.dropout(self.obs_encoder(x_)) x = x_.reshape(x.shape[0], x.shape[1], -1) o1 = self.core(x) out = self.head(o1['logit']) # layer_num+1 x memory_len x bs embedding_dim -> bs x layer_num+1 x memory_len x embedding_dim out['memory'] = o1['memory'].permute((2, 0, 1, 3)).contiguous() out['transformer_out'] = o1['logit'] # output of gtrxl, out['logit'] is final output return out
[docs] def reset_memory(self, batch_size: Optional[int] = None, state: Optional[torch.Tensor] = None) -> None: """ Overview: Clear or reset the memory of GTrXL. Arguments: - batch_size (:obj:`Optional[int]`): The number of samples in a training batch. - state (:obj:`Optional[torch.Tensor]`): The input memory data, whose shape is \ (layer_num, memory_len, bs, embedding_dim). """ self.core.reset_memory(batch_size, state)
[docs] def get_memory(self) -> Optional[torch.Tensor]: """ Overview: Return the memory of GTrXL. Returns: - memory: (:obj:`Optional[torch.Tensor]`): output memory or None if memory has not been initialized, \ whose shape is (layer_num, memory_len, bs, embedding_dim). """ return self.core.get_memory()