# Copyright (c) 2023 Amphion.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
import copy
from functools import partial
from typing import Any, Callable, List, Optional, Union
import torch
from torch import Tensor, nn
from torch.nn import functional as F
from modules.norms import AdaptiveLayerNorm, LayerNorm, BalancedBasicNorm, IdentityNorm
from modules.transformer import MultiheadAttention
from modules.general.scaling import BalancedDoubleSwish
class TransformerEncoderLayer(nn.Module):
__constants__ = ["batch_first", "norm_first"]
def __init__(
self,
d_model: int,
nhead: int,
dim_feedforward: int = 2048,
dropout: float = 0.1,
activation: Union[str, Callable[[Tensor], Tensor]] = F.relu,
batch_first: bool = False,
norm_first: bool = False,
device=None,
dtype=None,
linear1_self_attention_cls: nn.Module = nn.Linear,
linear2_self_attention_cls: nn.Module = nn.Linear,
linear1_feedforward_cls: nn.Module = nn.Linear,
linear2_feedforward_cls: nn.Module = nn.Linear,
layer_norm_cls: nn.Module = LayerNorm,
layer_norm_eps: float = 1e-5,
adaptive_layer_norm=False,
) -> None:
factory_kwargs = {"device": device, "dtype": dtype}
super(TransformerEncoderLayer, self).__init__()
self.self_attn = MultiheadAttention(
d_model,
nhead,
dropout=dropout,
batch_first=batch_first,
linear1_cls=linear1_self_attention_cls,
linear2_cls=linear2_self_attention_cls,
**factory_kwargs,
)
# Implementation of Feedforward model
self.linear1 = linear1_feedforward_cls(
d_model, dim_feedforward, **factory_kwargs
)
self.dropout = nn.Dropout(dropout)
self.linear2 = linear2_feedforward_cls(
dim_feedforward, d_model, **factory_kwargs
)
self.norm_first = norm_first
self.dropout1 = nn.Dropout(dropout)
self.dropout2 = nn.Dropout(dropout)
if isinstance(activation, str):
activation = _get_activation_fn(activation)
elif isinstance(activation, partial):
activation = activation(d_model)
elif activation == BalancedDoubleSwish:
activation = BalancedDoubleSwish(d_model)
self.activation = activation
norm1 = layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs)
if layer_norm_cls == IdentityNorm:
norm2 = BalancedBasicNorm(d_model, eps=layer_norm_eps, **factory_kwargs)
else:
norm2 = layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs)
if adaptive_layer_norm:
self.norm1 = AdaptiveLayerNorm(d_model, norm1)
self.norm2 = AdaptiveLayerNorm(d_model, norm2)
else:
self.norm1 = norm1
self.norm2 = norm2
def __setstate__(self, state):
super(TransformerEncoderLayer, self).__setstate__(state)
if not hasattr(self, "activation"):
self.activation = F.relu
def forward(
self,
src: Tensor,
src_mask: Optional[Tensor] = None,
src_key_padding_mask: Optional[Tensor] = None,
) -> Tensor:
r"""Pass the input through the encoder layer.
Args:
src: the sequence to the encoder layer (required).
src_mask: the mask for the src sequence (optional).
src_key_padding_mask: the mask for the src keys per batch (optional).
Shape:
see the docs in Transformer class.
"""
x, stage_embedding = src, None
is_src_tuple = False
if isinstance(src, tuple):
x, stage_embedding = src
is_src_tuple = True
if src_key_padding_mask is not None:
_skpm_dtype = src_key_padding_mask.dtype
if _skpm_dtype != torch.bool and not torch.is_floating_point(
src_key_padding_mask
):
raise AssertionError(
"only bool and floating types of key_padding_mask are supported"
)
if self.norm_first:
x = x + self._sa_block(
self.norm1(x, stage_embedding),
src_mask,
src_key_padding_mask,
)
x = x + self._ff_block(self.norm2(x, stage_embedding))
else:
x = self.norm1(
x + self._sa_block(x, src_mask, src_key_padding_mask),
stage_embedding,
)
x = self.norm2(x + self._ff_block(x), stage_embedding)
if is_src_tuple:
return (x, stage_embedding)
return x
def _sa_block(
self,
x: Tensor,
attn_mask: Optional[Tensor],
key_padding_mask: Optional[Tensor],
) -> Tensor:
x = self.self_attn(
x,
x,
x,
attn_mask=attn_mask,
key_padding_mask=key_padding_mask,
need_weights=False,
)[0]
return self.dropout1(x)
def _ff_block(self, x: Tensor) -> Tensor:
x = self.linear2(self.dropout(self.activation(self.linear1(x))))
return self.dropout2(x)
class TransformerEncoder(nn.Module):
"""TransformerEncoder is a stack of N encoder layers."""
def __init__(self, encoder_layer, num_layers, norm=None):
super(TransformerEncoder, self).__init__()
self.layers = _get_clones(encoder_layer, num_layers)
self.num_layers = num_layers
self.norm = norm
def forward(
self,
src: Tensor,
mask: Optional[Tensor] = None,
src_key_padding_mask: Optional[Tensor] = None,
return_layer_states: bool = False,
) -> Tensor:
# Pass the input through the encoder layers
output = src
layer_states = [] if return_layer_states else None
for mod in self.layers:
output = self._apply_module(
mod, output, mask, src_key_padding_mask, layer_states
)
if self.norm is not None:
output = self.norm(output)
return (layer_states, output) if return_layer_states else output
def _apply_module(self, module, output, mask, key_padding_mask, layer_states):
# Apply a single transformer module
output = module(output, src_mask=mask, src_key_padding_mask=key_padding_mask)
if layer_states is not None:
layer_states.append(output)
return output
class TransformerDecoderLayer(nn.Module):
__constants__ = ["batch_first", "norm_first"]
def __init__(
self,
d_model: int,
nhead: int,
dim_feedforward: int = 2048,
dropout: float = 0.1,
activation: Union[str, Callable[[Tensor], Tensor]] = F.relu,
linear1_self_attention_cls: nn.Module = nn.Linear,
linear2_self_attention_cls: nn.Module = nn.Linear,
linear1_feedforward_cls: nn.Module = nn.Linear,
linear2_feedforward_cls: nn.Module = nn.Linear,
batch_first: bool = False,
norm_first: bool = False,
device=None,
dtype=None,
layer_norm_cls: nn.Module = LayerNorm,
layer_norm_eps: float = 1e-5,
adaptive_layer_norm=False,
) -> None:
factory_kwargs = {"device": device, "dtype": dtype}
super(TransformerDecoderLayer, self).__init__()
self.self_attn = MultiheadAttention(
d_model,
nhead,
dropout=dropout,
batch_first=batch_first,
linear1_cls=linear1_self_attention_cls,
linear2_cls=linear2_self_attention_cls,
**factory_kwargs,
)
self.multihead_attn = MultiheadAttention(
d_model,
nhead,
dropout=dropout,
batch_first=batch_first,
linear1_cls=linear1_self_attention_cls,
linear2_cls=linear2_self_attention_cls,
**factory_kwargs,
)
self.linear1 = linear1_feedforward_cls(
d_model, dim_feedforward, **factory_kwargs
)
self.dropout = nn.Dropout(dropout)
self.linear2 = linear2_feedforward_cls(
dim_feedforward, d_model, **factory_kwargs
)
self.norm_first = norm_first
self.dropout1 = nn.Dropout(dropout)
self.dropout2 = nn.Dropout(dropout)
self.dropout3 = nn.Dropout(dropout)
self.activation = self._get_activation_fn(activation)
self.norm1, self.norm2, self.norm3 = self._init_norm_layers(
d_model, layer_norm_cls, layer_norm_eps, adaptive_layer_norm, factory_kwargs
)
def forward(
self,
tgt: Tensor,
memory: Tensor,
tgt_mask: Optional[Tensor] = None,
memory_mask: Optional[Tensor] = None,
tgt_key_padding_mask: Optional[Tensor] = None,
memory_key_padding_mask: Optional[Tensor] = None,
) -> Tensor:
r"""Pass the inputs (and mask) through the decoder layer.
Args:
tgt: the sequence to the decoder layer (required).
memory: the sequence from the last layer of the encoder (required).
tgt_mask: the mask for the tgt sequence (optional).
memory_mask: the mask for the memory sequence (optional).
tgt_key_padding_mask: the mask for the tgt keys per batch (optional).
memory_key_padding_mask: the mask for the memory keys per batch (optional).
Shape:
see the docs in Transformer class.
"""
tgt_is_tuple = False
if isinstance(tgt, tuple):
x, stage_embedding = tgt
tgt_is_tuple = True
else:
x, stage_embedding = tgt, None
if self.norm_first:
x = x + self._sa_block(
self.norm1(x, stage_embedding), tgt_mask, tgt_key_padding_mask
)
x = x + self._mha_block(
self.norm2(x, stage_embedding),
memory,
memory_mask,
memory_key_padding_mask,
)
x = x + self._ff_block(self.norm3(x, stage_embedding))
else:
x = self.norm1(
x + self._sa_block(x, tgt_mask, tgt_key_padding_mask),
stage_embedding,
)
x = self.norm2(
x + self._mha_block(x, memory, memory_mask, memory_key_padding_mask),
stage_embedding,
)
x = self.norm3(x + self._ff_block(x), stage_embedding)
if tgt_is_tuple:
return (x, stage_embedding)
return x
def _sa_block(
self,
x: Tensor,
attn_mask: Optional[Tensor],
key_padding_mask: Optional[Tensor],
) -> Tensor:
x = self.self_attn(
x,
x,
x,
attn_mask=attn_mask,
key_padding_mask=key_padding_mask,
need_weights=False,
)[0]
return self.dropout1(x)
def _mha_block(
self,
x: Tensor,
mem: Tensor,
attn_mask: Optional[Tensor],
key_padding_mask: Optional[Tensor],
) -> Tensor:
x = self.multihead_attn(
x,
mem,
mem,
attn_mask=attn_mask,
key_padding_mask=key_padding_mask,
need_weights=False,
)[0]
return self.dropout2(x)
def _ff_block(self, x: Tensor) -> Tensor:
x = self.linear2(self.dropout(self.activation(self.linear1(x))))
return self.dropout3(x)
def _get_activation_fn(self, activation):
if isinstance(activation, str):
return _get_activation_fn(activation)
elif callable(activation):
return activation
else:
raise ValueError("Unsupported activation type")
def _init_norm_layers(
self,
d_model,
layer_norm_cls,
layer_norm_eps,
adaptive_layer_norm,
factory_kwargs,
):
if adaptive_layer_norm:
return (
AdaptiveLayerNorm(
d_model,
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs),
),
AdaptiveLayerNorm(
d_model,
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs),
),
AdaptiveLayerNorm(
d_model,
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs),
),
)
else:
return (
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs),
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs),
layer_norm_cls(d_model, eps=layer_norm_eps, **factory_kwargs)
if layer_norm_cls != IdentityNorm
else BalancedBasicNorm(d_model, eps=layer_norm_eps, **factory_kwargs),
)
def _get_clones(module, N):
return nn.ModuleList([copy.deepcopy(module) for i in range(N)])
def _get_activation_fn(activation: str) -> Callable[[Tensor], Tensor]:
if activation == "relu":
return F.relu
elif activation == "gelu":
return F.gelu
raise RuntimeError("activation should be relu/gelu, not {}".format(activation))
class Transpose(nn.Identity):
"""(N, T, D) -> (N, D, T)"""
def forward(self, input: torch.Tensor) -> torch.Tensor:
return input.transpose(1, 2)