# modified from https://github.com/lifeiteng/vall-e/blob/main/valle/modules/transformer.py
import copy
import numbers
from functools import partial
from typing import Any
from typing import Callable
from typing import List
from typing import Optional
from typing import Tuple
from typing import Union
import torch
from AR.modules.activation_onnx import MultiheadAttention
from AR.modules.scaling import BalancedDoubleSwish
from torch import nn
from torch import Tensor
from torch.nn import functional as F
_shape_t = Union[int, List[int], torch.Size]
class LayerNorm(nn.Module):
__constants__ = ["normalized_shape", "eps", "elementwise_affine"]
normalized_shape: Tuple[int, ...]
eps: float
elementwise_affine: bool
def __init__(
self,
normalized_shape: _shape_t,
eps: float = 1e-5,
elementwise_affine: bool = True,
device=None,
dtype=None,
) -> None:
factory_kwargs = {"device": device, "dtype": dtype}
super(LayerNorm, self).__init__()
if isinstance(normalized_shape, numbers.Integral):
# mypy error: incompatible types in assignment
normalized_shape = (normalized_shape,) # type: ignore[assignment]
self.normalized_shape = tuple(normalized_shape) # type: ignore[arg-type]
self.eps = eps
self.elementwise_affine = elementwise_affine
if self.elementwise_affine:
self.weight = nn.Parameter(
torch.empty(self.normalized_shape, **factory_kwargs)
)
self.bias = nn.Parameter(
torch.empty(self.normalized_shape, **factory_kwargs)
)
else:
self.register_parameter("weight", None)
self.register_parameter("bias", None)
self.reset_parameters()
def reset_parameters(self) -> None:
if self.elementwise_affine:
nn.init.ones_(self.weight)
nn.init.zeros_(self.bias)
def forward(self, input: Tensor, embedding: Any = None) -> Tensor:
if isinstance(input, tuple):
input, embedding = input
return (
F.layer_norm(
input,
self.normalized_shape,
self.weight,
self.bias,
self.eps,
),
embedding,
)
assert embedding is None
return F.layer_norm(
input, self.normalized_shape, self.weight, self.bias, self.eps
)
def extra_repr(self) -> str:
return (
"{normalized_shape}, eps={eps}, "
"elementwise_affine={elementwise_affine}".format(**self.__dict__)
)
class IdentityNorm(nn.Module):
def __init__(
self,
d_model: int,
eps: float = 1e-5,
device=None,
dtype=None,
) -> None:
super(IdentityNorm, self).__init__()
def forward(self, input: Tensor, embedding: Any = None) -> Tensor:
if isinstance(input, tuple):
return input
assert embedding is None
return input
class TransformerEncoder(nn.Module):
r"""TransformerEncoder is a stack of N encoder layers. Users can build the
BERT(https://arxiv.org/abs/1810.04805) model with corresponding parameters.
Args:
encoder_layer: an instance of the TransformerEncoderLayer() class (required).
num_layers: the number of sub-encoder-layers in the encoder (required).
norm: the layer normalization component (optional).
enable_nested_tensor: if True, input will automatically convert to nested tensor
(and convert back on output). This will improve the overall performance of
TransformerEncoder when padding rate is high. Default: ``True`` (enabled).
Examples::
>>> encoder_layer = TransformerEncoderLayer(d_model=512, nhead=8)
>>> transformer_encoder = TransformerEncoder(encoder_layer, num_layers=6)
>>> src = torch.rand(10, 32, 512)
>>> out = transformer_encoder(src)
"""
__constants__ = ["norm"]
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,
cache=None,
) -> Tensor:
output = src
for mod in self.layers:
output = mod(
output,
src_mask=mask,
src_key_padding_mask=src_key_padding_mask,
cache=cache,
)
if self.norm is not None:
output = self.norm(output)
return output
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, # 512 16
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)
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,
cache=None,
) -> Tensor:
x = src
stage_embedding = None
x = self.norm1(
x + self._sa_block(x, src_mask, src_key_padding_mask, cache=cache),
stage_embedding,
)
x = self.norm2(x + self._ff_block(x), stage_embedding)
return x
def _sa_block(
self,
x: Tensor,
attn_mask: Optional[Tensor],
key_padding_mask: Optional[Tensor],
cache=None,
) -> Tensor:
x = self.self_attn(
x,
x,
x,
attn_mask=attn_mask,
key_padding_mask=key_padding_mask,
need_weights=False,
cache=cache,
)
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 AdaptiveLayerNorm(nn.Module):
r"""Adaptive Layer Normalization"""
def __init__(self, d_model, norm) -> None:
super(AdaptiveLayerNorm, self).__init__()
self.project_layer = nn.Linear(d_model, 2 * d_model)
self.norm = norm
self.d_model = d_model
self.eps = self.norm.eps
def forward(self, input: Tensor, embedding: Tensor = None) -> Tensor:
if isinstance(input, tuple):
input, embedding = input
weight, bias = torch.split(
self.project_layer(embedding),
split_size_or_sections=self.d_model,
dim=-1,
)
return (weight * self.norm(input) + bias, embedding)
weight, bias = torch.split(
self.project_layer(embedding),
split_size_or_sections=self.d_model,
dim=-1,
)
return weight * self.norm(input) + bias
def _get_clones(module, N):
return nn.ModuleList([copy.deepcopy(module) for i in range(N)])