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reusable parts from conformer_ctc

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egs/librispeech/ASR/streaming_conformer_ctc/asr_datamodule.py Symbolic link
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../conformer_ctc/asr_datamodule.py

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#!/usr/bin/env python3
# Copyright (c) 2021 University of Chinese Academy of Sciences (author: Han Zhu)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import math
import warnings
from typing import Optional, Tuple
import torch
from torch import Tensor, nn
from transformer import Supervisions, Transformer, encoder_padding_mask
class Conformer(Transformer):
"""
Args:
num_features (int): Number of input features
num_classes (int): Number of output classes
subsampling_factor (int): subsampling factor of encoder (the convolution layers before transformers)
d_model (int): attention dimension
nhead (int): number of head
dim_feedforward (int): feedforward dimention
num_encoder_layers (int): number of encoder layers
num_decoder_layers (int): number of decoder layers
dropout (float): dropout rate
cnn_module_kernel (int): Kernel size of convolution module
normalize_before (bool): whether to use layer_norm before the first block.
vgg_frontend (bool): whether to use vgg frontend.
"""
def __init__(
self,
num_features: int,
num_classes: int,
subsampling_factor: int = 4,
d_model: int = 256,
nhead: int = 4,
dim_feedforward: int = 2048,
num_encoder_layers: int = 12,
num_decoder_layers: int = 6,
dropout: float = 0.1,
cnn_module_kernel: int = 31,
normalize_before: bool = True,
vgg_frontend: bool = False,
use_feat_batchnorm: bool = False,
) -> None:
super(Conformer, self).__init__(
num_features=num_features,
num_classes=num_classes,
subsampling_factor=subsampling_factor,
d_model=d_model,
nhead=nhead,
dim_feedforward=dim_feedforward,
num_encoder_layers=num_encoder_layers,
num_decoder_layers=num_decoder_layers,
dropout=dropout,
normalize_before=normalize_before,
vgg_frontend=vgg_frontend,
use_feat_batchnorm=use_feat_batchnorm,
)
self.encoder_pos = RelPositionalEncoding(d_model, dropout)
encoder_layer = ConformerEncoderLayer(
d_model,
nhead,
dim_feedforward,
dropout,
cnn_module_kernel,
normalize_before,
)
self.encoder = ConformerEncoder(encoder_layer, num_encoder_layers)
self.normalize_before = normalize_before
if self.normalize_before:
self.after_norm = nn.LayerNorm(d_model)
else:
# Note: TorchScript detects that self.after_norm could be used inside forward()
# and throws an error without this change.
self.after_norm = identity
def run_encoder(
self, x: Tensor, supervisions: Optional[Supervisions] = None
) -> Tuple[Tensor, Optional[Tensor]]:
"""
Args:
x:
The model input. Its shape is (N, T, C).
supervisions:
Supervision in lhotse format.
See https://github.com/lhotse-speech/lhotse/blob/master/lhotse/dataset/speech_recognition.py#L32 # noqa
CAUTION: It contains length information, i.e., start and number of
frames, before subsampling
It is read directly from the batch, without any sorting. It is used
to compute encoder padding mask, which is used as memory key padding
mask for the decoder.
Returns:
Tensor: Predictor tensor of dimension (input_length, batch_size, d_model).
Tensor: Mask tensor of dimension (batch_size, input_length)
"""
x = self.encoder_embed(x)
x, pos_emb = self.encoder_pos(x)
x = x.permute(1, 0, 2) # (B, T, F) -> (T, B, F)
mask = encoder_padding_mask(x.size(0), supervisions)
if mask is not None:
mask = mask.to(x.device)
x = self.encoder(x, pos_emb, src_key_padding_mask=mask) # (T, B, F)
if self.normalize_before:
x = self.after_norm(x)
return x, mask
class ConformerEncoderLayer(nn.Module):
"""
ConformerEncoderLayer is made up of self-attn, feedforward and convolution networks.
See: "Conformer: Convolution-augmented Transformer for Speech Recognition"
Args:
d_model: the number of expected features in the input (required).
nhead: the number of heads in the multiheadattention models (required).
dim_feedforward: the dimension of the feedforward network model (default=2048).
dropout: the dropout value (default=0.1).
cnn_module_kernel (int): Kernel size of convolution module.
normalize_before: whether to use layer_norm before the first block.
Examples::
>>> encoder_layer = ConformerEncoderLayer(d_model=512, nhead=8)
>>> src = torch.rand(10, 32, 512)
>>> pos_emb = torch.rand(32, 19, 512)
>>> out = encoder_layer(src, pos_emb)
"""
def __init__(
self,
d_model: int,
nhead: int,
dim_feedforward: int = 2048,
dropout: float = 0.1,
cnn_module_kernel: int = 31,
normalize_before: bool = True,
) -> None:
super(ConformerEncoderLayer, self).__init__()
self.self_attn = RelPositionMultiheadAttention(
d_model, nhead, dropout=0.0
)
self.feed_forward = nn.Sequential(
nn.Linear(d_model, dim_feedforward),
Swish(),
nn.Dropout(dropout),
nn.Linear(dim_feedforward, d_model),
)
self.feed_forward_macaron = nn.Sequential(
nn.Linear(d_model, dim_feedforward),
Swish(),
nn.Dropout(dropout),
nn.Linear(dim_feedforward, d_model),
)
self.conv_module = ConvolutionModule(d_model, cnn_module_kernel)
self.norm_ff_macaron = nn.LayerNorm(
d_model
) # for the macaron style FNN module
self.norm_ff = nn.LayerNorm(d_model) # for the FNN module
self.norm_mha = nn.LayerNorm(d_model) # for the MHA module
self.ff_scale = 0.5
self.norm_conv = nn.LayerNorm(d_model) # for the CNN module
self.norm_final = nn.LayerNorm(
d_model
) # for the final output of the block
self.dropout = nn.Dropout(dropout)
self.normalize_before = normalize_before
def forward(
self,
src: Tensor,
pos_emb: Tensor,
src_mask: Optional[Tensor] = None,
src_key_padding_mask: Optional[Tensor] = None,
) -> Tensor:
"""
Pass the input through the encoder layer.
Args:
src: the sequence to the encoder layer (required).
pos_emb: Positional embedding tensor (required).
src_mask: the mask for the src sequence (optional).
src_key_padding_mask: the mask for the src keys per batch (optional).
Shape:
src: (S, N, E).
pos_emb: (N, 2*S-1, E)
src_mask: (S, S).
src_key_padding_mask: (N, S).
S is the source sequence length, N is the batch size, E is the feature number
"""
# macaron style feed forward module
residual = src
if self.normalize_before:
src = self.norm_ff_macaron(src)
src = residual + self.ff_scale * self.dropout(
self.feed_forward_macaron(src)
)
if not self.normalize_before:
src = self.norm_ff_macaron(src)
# multi-headed self-attention module
residual = src
if self.normalize_before:
src = self.norm_mha(src)
src_att = self.self_attn(
src,
src,
src,
pos_emb=pos_emb,
attn_mask=src_mask,
key_padding_mask=src_key_padding_mask,
)[0]
src = residual + self.dropout(src_att)
if not self.normalize_before:
src = self.norm_mha(src)
# convolution module
residual = src
if self.normalize_before:
src = self.norm_conv(src)
src = residual + self.dropout(self.conv_module(src))
if not self.normalize_before:
src = self.norm_conv(src)
# feed forward module
residual = src
if self.normalize_before:
src = self.norm_ff(src)
src = residual + self.ff_scale * self.dropout(self.feed_forward(src))
if not self.normalize_before:
src = self.norm_ff(src)
if self.normalize_before:
src = self.norm_final(src)
return src
class ConformerEncoder(nn.TransformerEncoder):
r"""ConformerEncoder is a stack of N encoder layers
Args:
encoder_layer: an instance of the ConformerEncoderLayer() class (required).
num_layers: the number of sub-encoder-layers in the encoder (required).
norm: the layer normalization component (optional).
Examples::
>>> encoder_layer = ConformerEncoderLayer(d_model=512, nhead=8)
>>> conformer_encoder = ConformerEncoder(encoder_layer, num_layers=6)
>>> src = torch.rand(10, 32, 512)
>>> pos_emb = torch.rand(32, 19, 512)
>>> out = conformer_encoder(src, pos_emb)
"""
def __init__(
self, encoder_layer: nn.Module, num_layers: int, norm: nn.Module = None
) -> None:
super(ConformerEncoder, self).__init__(
encoder_layer=encoder_layer, num_layers=num_layers, norm=norm
)
def forward(
self,
src: Tensor,
pos_emb: Tensor,
mask: Optional[Tensor] = None,
src_key_padding_mask: Optional[Tensor] = None,
) -> Tensor:
r"""Pass the input through the encoder layers in turn.
Args:
src: the sequence to the encoder (required).
pos_emb: Positional embedding tensor (required).
mask: the mask for the src sequence (optional).
src_key_padding_mask: the mask for the src keys per batch (optional).
Shape:
src: (S, N, E).
pos_emb: (N, 2*S-1, E)
mask: (S, S).
src_key_padding_mask: (N, S).
S is the source sequence length, T is the target sequence length, N is the batch size, E is the feature number
"""
output = src
for mod in self.layers:
output = mod(
output,
pos_emb,
src_mask=mask,
src_key_padding_mask=src_key_padding_mask,
)
if self.norm is not None:
output = self.norm(output)
return output
class RelPositionalEncoding(torch.nn.Module):
"""Relative positional encoding module.
See : Appendix B in "Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context"
Modified from https://github.com/espnet/espnet/blob/master/espnet/nets/pytorch_backend/transformer/embedding.py
Args:
d_model: Embedding dimension.
dropout_rate: Dropout rate.
max_len: Maximum input length.
"""
def __init__(
self, d_model: int, dropout_rate: float, max_len: int = 5000
) -> None:
"""Construct an PositionalEncoding object."""
super(RelPositionalEncoding, self).__init__()
self.d_model = d_model
self.xscale = math.sqrt(self.d_model)
self.dropout = torch.nn.Dropout(p=dropout_rate)
self.pe = None
self.extend_pe(torch.tensor(0.0).expand(1, max_len))
def extend_pe(self, x: Tensor) -> None:
"""Reset the positional encodings."""
if self.pe is not None:
# self.pe contains both positive and negative parts
# the length of self.pe is 2 * input_len - 1
if self.pe.size(1) >= x.size(1) * 2 - 1:
# Note: TorchScript doesn't implement operator== for torch.Device
if self.pe.dtype != x.dtype or str(self.pe.device) != str(
x.device
):
self.pe = self.pe.to(dtype=x.dtype, device=x.device)
return
# Suppose `i` means to the position of query vecotr and `j` means the
# position of key vector. We use position relative positions when keys
# are to the left (i>j) and negative relative positions otherwise (i<j).
pe_positive = torch.zeros(x.size(1), self.d_model)
pe_negative = torch.zeros(x.size(1), self.d_model)
position = torch.arange(0, x.size(1), dtype=torch.float32).unsqueeze(1)
div_term = torch.exp(
torch.arange(0, self.d_model, 2, dtype=torch.float32)
* -(math.log(10000.0) / self.d_model)
)
pe_positive[:, 0::2] = torch.sin(position * div_term)
pe_positive[:, 1::2] = torch.cos(position * div_term)
pe_negative[:, 0::2] = torch.sin(-1 * position * div_term)
pe_negative[:, 1::2] = torch.cos(-1 * position * div_term)
# Reserve the order of positive indices and concat both positive and
# negative indices. This is used to support the shifting trick
# as in "Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context"
pe_positive = torch.flip(pe_positive, [0]).unsqueeze(0)
pe_negative = pe_negative[1:].unsqueeze(0)
pe = torch.cat([pe_positive, pe_negative], dim=1)
self.pe = pe.to(device=x.device, dtype=x.dtype)
def forward(self, x: torch.Tensor) -> Tuple[Tensor, Tensor]:
"""Add positional encoding.
Args:
x (torch.Tensor): Input tensor (batch, time, `*`).
Returns:
torch.Tensor: Encoded tensor (batch, time, `*`).
torch.Tensor: Encoded tensor (batch, 2*time-1, `*`).
"""
self.extend_pe(x)
x = x * self.xscale
pos_emb = self.pe[
:,
self.pe.size(1) // 2
- x.size(1)
+ 1 : self.pe.size(1) // 2 # noqa E203
+ x.size(1),
]
return self.dropout(x), self.dropout(pos_emb)
class RelPositionMultiheadAttention(nn.Module):
r"""Multi-Head Attention layer with relative position encoding
See reference: "Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context"
Args:
embed_dim: total dimension of the model.
num_heads: parallel attention heads.
dropout: a Dropout layer on attn_output_weights. Default: 0.0.
Examples::
>>> rel_pos_multihead_attn = RelPositionMultiheadAttention(embed_dim, num_heads)
>>> attn_output, attn_output_weights = multihead_attn(query, key, value, pos_emb)
"""
def __init__(
self,
embed_dim: int,
num_heads: int,
dropout: float = 0.0,
) -> None:
super(RelPositionMultiheadAttention, self).__init__()
self.embed_dim = embed_dim
self.num_heads = num_heads
self.dropout = dropout
self.head_dim = embed_dim // num_heads
assert (
self.head_dim * num_heads == self.embed_dim
), "embed_dim must be divisible by num_heads"
self.in_proj = nn.Linear(embed_dim, 3 * embed_dim, bias=True)
self.out_proj = nn.Linear(embed_dim, embed_dim, bias=True)
# linear transformation for positional encoding.
self.linear_pos = nn.Linear(embed_dim, embed_dim, bias=False)
# these two learnable bias are used in matrix c and matrix d
# as described in "Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context" Section 3.3
self.pos_bias_u = nn.Parameter(torch.Tensor(num_heads, self.head_dim))
self.pos_bias_v = nn.Parameter(torch.Tensor(num_heads, self.head_dim))
self._reset_parameters()
def _reset_parameters(self) -> None:
nn.init.xavier_uniform_(self.in_proj.weight)
nn.init.constant_(self.in_proj.bias, 0.0)
nn.init.constant_(self.out_proj.bias, 0.0)
nn.init.xavier_uniform_(self.pos_bias_u)
nn.init.xavier_uniform_(self.pos_bias_v)
def forward(
self,
query: Tensor,
key: Tensor,
value: Tensor,
pos_emb: Tensor,
key_padding_mask: Optional[Tensor] = None,
need_weights: bool = True,
attn_mask: Optional[Tensor] = None,
) -> Tuple[Tensor, Optional[Tensor]]:
r"""
Args:
query, key, value: map a query and a set of key-value pairs to an output.
pos_emb: Positional embedding tensor
key_padding_mask: if provided, specified padding elements in the key will
be ignored by the attention. When given a binary mask and a value is True,
the corresponding value on the attention layer will be ignored. When given
a byte mask and a value is non-zero, the corresponding value on the attention
layer will be ignored
need_weights: output attn_output_weights.
attn_mask: 2D or 3D mask that prevents attention to certain positions. A 2D mask will be broadcasted for all
the batches while a 3D mask allows to specify a different mask for the entries of each batch.
Shape:
- Inputs:
- query: :math:`(L, N, E)` where L is the target sequence length, N is the batch size, E is
the embedding dimension.
- key: :math:`(S, N, E)`, where S is the source sequence length, N is the batch size, E is
the embedding dimension.
- value: :math:`(S, N, E)` where S is the source sequence length, N is the batch size, E is
the embedding dimension.
- pos_emb: :math:`(N, 2*L-1, E)` where L is the target sequence length, N is the batch size, E is
the embedding dimension.
- key_padding_mask: :math:`(N, S)` where N is the batch size, S is the source sequence length.
If a ByteTensor is provided, the non-zero positions will be ignored while the position
with the zero positions will be unchanged. If a BoolTensor is provided, the positions with the
value of ``True`` will be ignored while the position with the value of ``False`` will be unchanged.
- attn_mask: 2D mask :math:`(L, S)` where L is the target sequence length, S is the source sequence length.
3D mask :math:`(N*num_heads, L, S)` where N is the batch size, L is the target sequence length,
S is the source sequence length. attn_mask ensure that position i is allowed to attend the unmasked
positions. If a ByteTensor is provided, the non-zero positions are not allowed to attend
while the zero positions will be unchanged. If a BoolTensor is provided, positions with ``True``
is not allowed to attend while ``False`` values will be unchanged. If a FloatTensor
is provided, it will be added to the attention weight.
- Outputs:
- attn_output: :math:`(L, N, E)` where L is the target sequence length, N is the batch size,
E is the embedding dimension.
- attn_output_weights: :math:`(N, L, S)` where N is the batch size,
L is the target sequence length, S is the source sequence length.
"""
return self.multi_head_attention_forward(
query,
key,
value,
pos_emb,
self.embed_dim,
self.num_heads,
self.in_proj.weight,
self.in_proj.bias,
self.dropout,
self.out_proj.weight,
self.out_proj.bias,
training=self.training,
key_padding_mask=key_padding_mask,
need_weights=need_weights,
attn_mask=attn_mask,
)
def rel_shift(self, x: Tensor) -> Tensor:
"""Compute relative positional encoding.
Args:
x: Input tensor (batch, head, time1, 2*time1-1).
time1 means the length of query vector.
Returns:
Tensor: tensor of shape (batch, head, time1, time2)
(note: time2 has the same value as time1, but it is for
the key, while time1 is for the query).
"""
(batch_size, num_heads, time1, n) = x.shape
assert n == 2 * time1 - 1
# Note: TorchScript requires explicit arg for stride()
batch_stride = x.stride(0)
head_stride = x.stride(1)
time1_stride = x.stride(2)
n_stride = x.stride(3)
return x.as_strided(
(batch_size, num_heads, time1, time1),
(batch_stride, head_stride, time1_stride - n_stride, n_stride),
storage_offset=n_stride * (time1 - 1),
)
def multi_head_attention_forward(
self,
query: Tensor,
key: Tensor,
value: Tensor,
pos_emb: Tensor,
embed_dim_to_check: int,
num_heads: int,
in_proj_weight: Tensor,
in_proj_bias: Tensor,
dropout_p: float,
out_proj_weight: Tensor,
out_proj_bias: Tensor,
training: bool = True,
key_padding_mask: Optional[Tensor] = None,
need_weights: bool = True,
attn_mask: Optional[Tensor] = None,
) -> Tuple[Tensor, Optional[Tensor]]:
r"""
Args:
query, key, value: map a query and a set of key-value pairs to an output.
pos_emb: Positional embedding tensor
embed_dim_to_check: total dimension of the model.
num_heads: parallel attention heads.
in_proj_weight, in_proj_bias: input projection weight and bias.
dropout_p: probability of an element to be zeroed.
out_proj_weight, out_proj_bias: the output projection weight and bias.
training: apply dropout if is ``True``.
key_padding_mask: if provided, specified padding elements in the key will
be ignored by the attention. This is an binary mask. When the value is True,
the corresponding value on the attention layer will be filled with -inf.
need_weights: output attn_output_weights.
attn_mask: 2D or 3D mask that prevents attention to certain positions. A 2D mask will be broadcasted for all
the batches while a 3D mask allows to specify a different mask for the entries of each batch.
Shape:
Inputs:
- query: :math:`(L, N, E)` where L is the target sequence length, N is the batch size, E is
the embedding dimension.
- key: :math:`(S, N, E)`, where S is the source sequence length, N is the batch size, E is
the embedding dimension.
- value: :math:`(S, N, E)` where S is the source sequence length, N is the batch size, E is
the embedding dimension.
- pos_emb: :math:`(N, 2*L-1, E)` or :math:`(1, 2*L-1, E)` where L is the target sequence
length, N is the batch size, E is the embedding dimension.
- key_padding_mask: :math:`(N, S)` where N is the batch size, S is the source sequence length.
If a ByteTensor is provided, the non-zero positions will be ignored while the zero positions
will be unchanged. If a BoolTensor is provided, the positions with the
value of ``True`` will be ignored while the position with the value of ``False`` will be unchanged.
- attn_mask: 2D mask :math:`(L, S)` where L is the target sequence length, S is the source sequence length.
3D mask :math:`(N*num_heads, L, S)` where N is the batch size, L is the target sequence length,
S is the source sequence length. attn_mask ensures that position i is allowed to attend the unmasked
positions. If a ByteTensor is provided, the non-zero positions are not allowed to attend
while the zero positions will be unchanged. If a BoolTensor is provided, positions with ``True``
are not allowed to attend while ``False`` values will be unchanged. If a FloatTensor
is provided, it will be added to the attention weight.
Outputs:
- attn_output: :math:`(L, N, E)` where L is the target sequence length, N is the batch size,
E is the embedding dimension.
- attn_output_weights: :math:`(N, L, S)` where N is the batch size,
L is the target sequence length, S is the source sequence length.
"""
tgt_len, bsz, embed_dim = query.size()
assert embed_dim == embed_dim_to_check
assert key.size(0) == value.size(0) and key.size(1) == value.size(1)
head_dim = embed_dim // num_heads
assert (
head_dim * num_heads == embed_dim
), "embed_dim must be divisible by num_heads"
scaling = float(head_dim) ** -0.5
if torch.equal(query, key) and torch.equal(key, value):
# self-attention
q, k, v = nn.functional.linear(
query, in_proj_weight, in_proj_bias
).chunk(3, dim=-1)
elif torch.equal(key, value):
# encoder-decoder attention
# This is inline in_proj function with in_proj_weight and in_proj_bias
_b = in_proj_bias
_start = 0
_end = embed_dim
_w = in_proj_weight[_start:_end, :]
if _b is not None:
_b = _b[_start:_end]
q = nn.functional.linear(query, _w, _b)
# This is inline in_proj function with in_proj_weight and in_proj_bias
_b = in_proj_bias
_start = embed_dim
_end = None
_w = in_proj_weight[_start:, :]
if _b is not None:
_b = _b[_start:]
k, v = nn.functional.linear(key, _w, _b).chunk(2, dim=-1)
else:
# This is inline in_proj function with in_proj_weight and in_proj_bias
_b = in_proj_bias
_start = 0
_end = embed_dim
_w = in_proj_weight[_start:_end, :]
if _b is not None:
_b = _b[_start:_end]
q = nn.functional.linear(query, _w, _b)
# This is inline in_proj function with in_proj_weight and in_proj_bias
_b = in_proj_bias
_start = embed_dim
_end = embed_dim * 2
_w = in_proj_weight[_start:_end, :]
if _b is not None:
_b = _b[_start:_end]
k = nn.functional.linear(key, _w, _b)
# This is inline in_proj function with in_proj_weight and in_proj_bias
_b = in_proj_bias
_start = embed_dim * 2
_end = None
_w = in_proj_weight[_start:, :]
if _b is not None:
_b = _b[_start:]
v = nn.functional.linear(value, _w, _b)
if attn_mask is not None:
assert (
attn_mask.dtype == torch.float32
or attn_mask.dtype == torch.float64
or attn_mask.dtype == torch.float16
or attn_mask.dtype == torch.uint8
or attn_mask.dtype == torch.bool
), "Only float, byte, and bool types are supported for attn_mask, not {}".format(
attn_mask.dtype
)
if attn_mask.dtype == torch.uint8:
warnings.warn(
"Byte tensor for attn_mask is deprecated. Use bool tensor instead."
)
attn_mask = attn_mask.to(torch.bool)
if attn_mask.dim() == 2:
attn_mask = attn_mask.unsqueeze(0)
if list(attn_mask.size()) != [1, query.size(0), key.size(0)]:
raise RuntimeError(
"The size of the 2D attn_mask is not correct."
)
elif attn_mask.dim() == 3:
if list(attn_mask.size()) != [
bsz * num_heads,
query.size(0),
key.size(0),
]:
raise RuntimeError(
"The size of the 3D attn_mask is not correct."
)
else:
raise RuntimeError(
"attn_mask's dimension {} is not supported".format(
attn_mask.dim()
)
)
# attn_mask's dim is 3 now.
# convert ByteTensor key_padding_mask to bool
if (
key_padding_mask is not None
and key_padding_mask.dtype == torch.uint8
):
warnings.warn(
"Byte tensor for key_padding_mask is deprecated. Use bool tensor instead."
)
key_padding_mask = key_padding_mask.to(torch.bool)
q = q.contiguous().view(tgt_len, bsz, num_heads, head_dim)
k = k.contiguous().view(-1, bsz, num_heads, head_dim)
v = v.contiguous().view(-1, bsz * num_heads, head_dim).transpose(0, 1)
src_len = k.size(0)
if key_padding_mask is not None:
assert key_padding_mask.size(0) == bsz, "{} == {}".format(
key_padding_mask.size(0), bsz
)
assert key_padding_mask.size(1) == src_len, "{} == {}".format(
key_padding_mask.size(1), src_len
)
q = q.transpose(0, 1) # (batch, time1, head, d_k)
pos_emb_bsz = pos_emb.size(0)
assert pos_emb_bsz in (1, bsz) # actually it is 1
p = self.linear_pos(pos_emb).view(pos_emb_bsz, -1, num_heads, head_dim)
p = p.transpose(1, 2) # (batch, head, 2*time1-1, d_k)
q_with_bias_u = (q + self.pos_bias_u).transpose(
1, 2
) # (batch, head, time1, d_k)
q_with_bias_v = (q + self.pos_bias_v).transpose(
1, 2
) # (batch, head, time1, d_k)
# compute attention score
# first compute matrix a and matrix c
# as described in "Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context" Section 3.3
k = k.permute(1, 2, 3, 0) # (batch, head, d_k, time2)
matrix_ac = torch.matmul(
q_with_bias_u, k
) # (batch, head, time1, time2)
# compute matrix b and matrix d
matrix_bd = torch.matmul(
q_with_bias_v, p.transpose(-2, -1)
) # (batch, head, time1, 2*time1-1)
matrix_bd = self.rel_shift(matrix_bd)
attn_output_weights = (
matrix_ac + matrix_bd
) * scaling # (batch, head, time1, time2)
attn_output_weights = attn_output_weights.view(
bsz * num_heads, tgt_len, -1
)
assert list(attn_output_weights.size()) == [
bsz * num_heads,
tgt_len,
src_len,
]
if attn_mask is not None:
if attn_mask.dtype == torch.bool:
attn_output_weights.masked_fill_(attn_mask, float("-inf"))
else:
attn_output_weights += attn_mask
if key_padding_mask is not None:
attn_output_weights = attn_output_weights.view(
bsz, num_heads, tgt_len, src_len
)
attn_output_weights = attn_output_weights.masked_fill(
key_padding_mask.unsqueeze(1).unsqueeze(2),
float("-inf"),
)
attn_output_weights = attn_output_weights.view(
bsz * num_heads, tgt_len, src_len
)
attn_output_weights = nn.functional.softmax(attn_output_weights, dim=-1)
attn_output_weights = nn.functional.dropout(
attn_output_weights, p=dropout_p, training=training
)
attn_output = torch.bmm(attn_output_weights, v)
assert list(attn_output.size()) == [bsz * num_heads, tgt_len, head_dim]
attn_output = (
attn_output.transpose(0, 1)
.contiguous()
.view(tgt_len, bsz, embed_dim)
)
attn_output = nn.functional.linear(
attn_output, out_proj_weight, out_proj_bias
)
if need_weights:
# average attention weights over heads
attn_output_weights = attn_output_weights.view(
bsz, num_heads, tgt_len, src_len
)
return attn_output, attn_output_weights.sum(dim=1) / num_heads
else:
return attn_output, None
class ConvolutionModule(nn.Module):
"""ConvolutionModule in Conformer model.
Modified from https://github.com/espnet/espnet/blob/master/espnet/nets/pytorch_backend/conformer/convolution.py
Args:
channels (int): The number of channels of conv layers.
kernel_size (int): Kernerl size of conv layers.
bias (bool): Whether to use bias in conv layers (default=True).
"""
def __init__(
self, channels: int, kernel_size: int, bias: bool = True
) -> None:
"""Construct an ConvolutionModule object."""
super(ConvolutionModule, self).__init__()
# kernerl_size should be a odd number for 'SAME' padding
assert (kernel_size - 1) % 2 == 0
self.pointwise_conv1 = nn.Conv1d(
channels,
2 * channels,
kernel_size=1,
stride=1,
padding=0,
bias=bias,
)
self.depthwise_conv = nn.Conv1d(
channels,
channels,
kernel_size,
stride=1,
padding=(kernel_size - 1) // 2,
groups=channels,
bias=bias,
)
self.norm = nn.BatchNorm1d(channels)
self.pointwise_conv2 = nn.Conv1d(
channels,
channels,
kernel_size=1,
stride=1,
padding=0,
bias=bias,
)
self.activation = Swish()
def forward(self, x: Tensor) -> Tensor:
"""Compute convolution module.
Args:
x: Input tensor (#time, batch, channels).
Returns:
Tensor: Output tensor (#time, batch, channels).
"""
# exchange the temporal dimension and the feature dimension
x = x.permute(1, 2, 0) # (#batch, channels, time).
# GLU mechanism
x = self.pointwise_conv1(x) # (batch, 2*channels, time)
x = nn.functional.glu(x, dim=1) # (batch, channels, time)
# 1D Depthwise Conv
x = self.depthwise_conv(x)
x = self.activation(self.norm(x))
x = self.pointwise_conv2(x) # (batch, channel, time)
return x.permute(2, 0, 1)
class Swish(torch.nn.Module):
"""Construct an Swish object."""
def forward(self, x: Tensor) -> Tensor:
"""Return Swich activation function."""
return x * torch.sigmoid(x)
def identity(x):
return x

1
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../conformer_ctc/label_smoothing.py

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../conformer_ctc/subsampling.py

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egs/librispeech/ASR/streaming_conformer_ctc/train.py Executable file
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#!/usr/bin/env python3
# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang,
# Wei Kang
# Mingshuang Luo)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import argparse
import logging
from pathlib import Path
from shutil import copyfile
from typing import Optional, Tuple
import k2
import torch
import torch.multiprocessing as mp
import torch.nn as nn
from asr_datamodule import LibriSpeechAsrDataModule
from conformer import Conformer
from lhotse.utils import fix_random_seed
from torch import Tensor
from torch.nn.parallel import DistributedDataParallel as DDP
from torch.nn.utils import clip_grad_norm_
from torch.utils.tensorboard import SummaryWriter
from transformer import Noam
from icefall.bpe_graph_compiler import BpeCtcTrainingGraphCompiler
from icefall.checkpoint import load_checkpoint
from icefall.checkpoint import save_checkpoint as save_checkpoint_impl
from icefall.dist import cleanup_dist, setup_dist
from icefall.env import get_env_info
from icefall.lexicon import Lexicon
from icefall.utils import (
AttributeDict,
MetricsTracker,
encode_supervisions,
setup_logger,
str2bool,
)
def get_parser():
parser = argparse.ArgumentParser(
formatter_class=argparse.ArgumentDefaultsHelpFormatter
)
parser.add_argument(
"--world-size",
type=int,
default=1,
help="Number of GPUs for DDP training.",
)
parser.add_argument(
"--master-port",
type=int,
default=12354,
help="Master port to use for DDP training.",
)
parser.add_argument(
"--tensorboard",
type=str2bool,
default=True,
help="Should various information be logged in tensorboard.",
)
parser.add_argument(
"--num-epochs",
type=int,
default=78,
help="Number of epochs to train.",
)
parser.add_argument(
"--start-epoch",
type=int,
default=0,
help="""Resume training from from this epoch.
If it is positive, it will load checkpoint from
conformer_ctc/exp/epoch-{start_epoch-1}.pt
""",
)
parser.add_argument(
"--exp-dir",
type=str,
default="conformer_ctc/exp",
help="""The experiment dir.
It specifies the directory where all training related
files, e.g., checkpoints, log, etc, are saved
""",
)
parser.add_argument(
"--lang-dir",
type=str,
default="data/lang_bpe_500",
help="""The lang dir
It contains language related input files such as
"lexicon.txt"
""",
)
parser.add_argument(
"--att-rate",
type=float,
default=0.8,
help="""The attention rate.
The total loss is (1 - att_rate) * ctc_loss + att_rate * att_loss
""",
)
return parser
def get_params() -> AttributeDict:
"""Return a dict containing training parameters.
All training related parameters that are not passed from the commandline
are saved in the variable `params`.
Commandline options are merged into `params` after they are parsed, so
you can also access them via `params`.
Explanation of options saved in `params`:
- best_train_loss: Best training loss so far. It is used to select
the model that has the lowest training loss. It is
updated during the training.
- best_valid_loss: Best validation loss so far. It is used to select
the model that has the lowest validation loss. It is
updated during the training.
- best_train_epoch: It is the epoch that has the best training loss.
- best_valid_epoch: It is the epoch that has the best validation loss.
- batch_idx_train: Used to writing statistics to tensorboard. It
contains number of batches trained so far across
epochs.
- log_interval: Print training loss if batch_idx % log_interval` is 0
- reset_interval: Reset statistics if batch_idx % reset_interval is 0
- valid_interval: Run validation if batch_idx % valid_interval is 0
- feature_dim: The model input dim. It has to match the one used
in computing features.
- subsampling_factor: The subsampling factor for the model.
- use_feat_batchnorm: Whether to do batch normalization for the
input features.
- attention_dim: Hidden dim for multi-head attention model.
- head: Number of heads of multi-head attention model.
- num_decoder_layers: Number of decoder layer of transformer decoder.
- beam_size: It is used in k2.ctc_loss
- reduction: It is used in k2.ctc_loss
- use_double_scores: It is used in k2.ctc_loss
- weight_decay: The weight_decay for the optimizer.
- lr_factor: The lr_factor for Noam optimizer.
- warm_step: The warm_step for Noam optimizer.
"""
params = AttributeDict(
{
"best_train_loss": float("inf"),
"best_valid_loss": float("inf"),
"best_train_epoch": -1,
"best_valid_epoch": -1,
"batch_idx_train": 0,
"log_interval": 50,
"reset_interval": 200,
"valid_interval": 3000,
# parameters for conformer
"feature_dim": 80,
"subsampling_factor": 4,
"use_feat_batchnorm": True,
"attention_dim": 512,
"nhead": 8,
"num_decoder_layers": 6,
# parameters for loss
"beam_size": 10,
"reduction": "sum",
"use_double_scores": True,
# parameters for Noam
"weight_decay": 1e-6,
"lr_factor": 5.0,
"warm_step": 80000,
"env_info": get_env_info(),
}
)
return params
def load_checkpoint_if_available(
params: AttributeDict,
model: nn.Module,
optimizer: Optional[torch.optim.Optimizer] = None,
scheduler: Optional[torch.optim.lr_scheduler._LRScheduler] = None,
) -> None:
"""Load checkpoint from file.
If params.start_epoch is positive, it will load the checkpoint from
`params.start_epoch - 1`. Otherwise, this function does nothing.
Apart from loading state dict for `model`, `optimizer` and `scheduler`,
it also updates `best_train_epoch`, `best_train_loss`, `best_valid_epoch`,
and `best_valid_loss` in `params`.
Args:
params:
The return value of :func:`get_params`.
model:
The training model.
optimizer:
The optimizer that we are using.
scheduler:
The learning rate scheduler we are using.
Returns:
Return None.
"""
if params.start_epoch <= 0:
return
filename = params.exp_dir / f"epoch-{params.start_epoch-1}.pt"
saved_params = load_checkpoint(
filename,
model=model,
optimizer=optimizer,
scheduler=scheduler,
)
keys = [
"best_train_epoch",
"best_valid_epoch",
"batch_idx_train",
"best_train_loss",
"best_valid_loss",
]
for k in keys:
params[k] = saved_params[k]
return saved_params
def save_checkpoint(
params: AttributeDict,
model: nn.Module,
optimizer: Optional[torch.optim.Optimizer] = None,
scheduler: Optional[torch.optim.lr_scheduler._LRScheduler] = None,
rank: int = 0,
) -> None:
"""Save model, optimizer, scheduler and training stats to file.
Args:
params:
It is returned by :func:`get_params`.
model:
The training model.
"""
if rank != 0:
return
filename = params.exp_dir / f"epoch-{params.cur_epoch}.pt"
save_checkpoint_impl(
filename=filename,
model=model,
params=params,
optimizer=optimizer,
scheduler=scheduler,
rank=rank,
)
if params.best_train_epoch == params.cur_epoch:
best_train_filename = params.exp_dir / "best-train-loss.pt"
copyfile(src=filename, dst=best_train_filename)
if params.best_valid_epoch == params.cur_epoch:
best_valid_filename = params.exp_dir / "best-valid-loss.pt"
copyfile(src=filename, dst=best_valid_filename)
def compute_loss(
params: AttributeDict,
model: nn.Module,
batch: dict,
graph_compiler: BpeCtcTrainingGraphCompiler,
is_training: bool,
) -> Tuple[Tensor, MetricsTracker]:
"""
Compute CTC loss given the model and its inputs.
Args:
params:
Parameters for training. See :func:`get_params`.
model:
The model for training. It is an instance of Conformer in our case.
batch:
A batch of data. See `lhotse.dataset.K2SpeechRecognitionDataset()`
for the content in it.
graph_compiler:
It is used to build a decoding graph from a ctc topo and training
transcript. The training transcript is contained in the given `batch`,
while the ctc topo is built when this compiler is instantiated.
is_training:
True for training. False for validation. When it is True, this
function enables autograd during computation; when it is False, it
disables autograd.
"""
device = graph_compiler.device
feature = batch["inputs"]
# at entry, feature is (N, T, C)
assert feature.ndim == 3
feature = feature.to(device)
supervisions = batch["supervisions"]
with torch.set_grad_enabled(is_training):
nnet_output, encoder_memory, memory_mask = model(feature, supervisions)
# nnet_output is (N, T, C)
# NOTE: We need `encode_supervisions` to sort sequences with
# different duration in decreasing order, required by
# `k2.intersect_dense` called in `k2.ctc_loss`
supervision_segments, texts = encode_supervisions(
supervisions, subsampling_factor=params.subsampling_factor
)
token_ids = graph_compiler.texts_to_ids(texts)
decoding_graph = graph_compiler.compile(token_ids)
dense_fsa_vec = k2.DenseFsaVec(
nnet_output,
supervision_segments,
allow_truncate=params.subsampling_factor - 1,
)
ctc_loss = k2.ctc_loss(
decoding_graph=decoding_graph,
dense_fsa_vec=dense_fsa_vec,
output_beam=params.beam_size,
reduction=params.reduction,
use_double_scores=params.use_double_scores,
)
if params.att_rate != 0.0:
with torch.set_grad_enabled(is_training):
mmodel = model.module if hasattr(model, "module") else model
# Note: We need to generate an unsorted version of token_ids
# `encode_supervisions()` called above sorts text, but
# encoder_memory and memory_mask are not sorted, so we
# use an unsorted version `supervisions["text"]` to regenerate
# the token_ids
#
# See https://github.com/k2-fsa/icefall/issues/97
# for more details
unsorted_token_ids = graph_compiler.texts_to_ids(
supervisions["text"]
)
att_loss = mmodel.decoder_forward(
encoder_memory,
memory_mask,
token_ids=unsorted_token_ids,
sos_id=graph_compiler.sos_id,
eos_id=graph_compiler.eos_id,
)
loss = (1.0 - params.att_rate) * ctc_loss + params.att_rate * att_loss
else:
loss = ctc_loss
att_loss = torch.tensor([0])
assert loss.requires_grad == is_training
info = MetricsTracker()
info["frames"] = supervision_segments[:, 2].sum().item()
info["ctc_loss"] = ctc_loss.detach().cpu().item()
if params.att_rate != 0.0:
info["att_loss"] = att_loss.detach().cpu().item()
info["loss"] = loss.detach().cpu().item()
return loss, info
def compute_validation_loss(
params: AttributeDict,
model: nn.Module,
graph_compiler: BpeCtcTrainingGraphCompiler,
valid_dl: torch.utils.data.DataLoader,
world_size: int = 1,
) -> MetricsTracker:
"""Run the validation process."""
model.eval()
tot_loss = MetricsTracker()
for batch_idx, batch in enumerate(valid_dl):
loss, loss_info = compute_loss(
params=params,
model=model,
batch=batch,
graph_compiler=graph_compiler,
is_training=False,
)
assert loss.requires_grad is False
tot_loss = tot_loss + loss_info
if world_size > 1:
tot_loss.reduce(loss.device)
loss_value = tot_loss["loss"] / tot_loss["frames"]
if loss_value < params.best_valid_loss:
params.best_valid_epoch = params.cur_epoch
params.best_valid_loss = loss_value
return tot_loss
def train_one_epoch(
params: AttributeDict,
model: nn.Module,
optimizer: torch.optim.Optimizer,
graph_compiler: BpeCtcTrainingGraphCompiler,
train_dl: torch.utils.data.DataLoader,
valid_dl: torch.utils.data.DataLoader,
tb_writer: Optional[SummaryWriter] = None,
world_size: int = 1,
) -> None:
"""Train the model for one epoch.
The training loss from the mean of all frames is saved in
`params.train_loss`. It runs the validation process every
`params.valid_interval` batches.
Args:
params:
It is returned by :func:`get_params`.
model:
The model for training.
optimizer:
The optimizer we are using.
graph_compiler:
It is used to convert transcripts to FSAs.
train_dl:
Dataloader for the training dataset.
valid_dl:
Dataloader for the validation dataset.
tb_writer:
Writer to write log messages to tensorboard.
world_size:
Number of nodes in DDP training. If it is 1, DDP is disabled.
"""
model.train()
tot_loss = MetricsTracker()
for batch_idx, batch in enumerate(train_dl):
params.batch_idx_train += 1
batch_size = len(batch["supervisions"]["text"])
loss, loss_info = compute_loss(
params=params,
model=model,
batch=batch,
graph_compiler=graph_compiler,
is_training=True,
)
# summary stats
tot_loss = (tot_loss * (1 - 1 / params.reset_interval)) + loss_info
# NOTE: We use reduction==sum and loss is computed over utterances
# in the batch and there is no normalization to it so far.
optimizer.zero_grad()
loss.backward()
clip_grad_norm_(model.parameters(), 5.0, 2.0)
optimizer.step()
if batch_idx % params.log_interval == 0:
logging.info(
f"Epoch {params.cur_epoch}, "
f"batch {batch_idx}, loss[{loss_info}], "
f"tot_loss[{tot_loss}], batch size: {batch_size}"
)
if batch_idx % params.log_interval == 0:
if tb_writer is not None:
loss_info.write_summary(
tb_writer, "train/current_", params.batch_idx_train
)
tot_loss.write_summary(
tb_writer, "train/tot_", params.batch_idx_train
)
if batch_idx > 0 and batch_idx % params.valid_interval == 0:
logging.info("Computing validation loss")
valid_info = compute_validation_loss(
params=params,
model=model,
graph_compiler=graph_compiler,
valid_dl=valid_dl,
world_size=world_size,
)
model.train()
logging.info(f"Epoch {params.cur_epoch}, validation: {valid_info}")
if tb_writer is not None:
valid_info.write_summary(
tb_writer, "train/valid_", params.batch_idx_train
)
loss_value = tot_loss["loss"] / tot_loss["frames"]
params.train_loss = loss_value
if params.train_loss < params.best_train_loss:
params.best_train_epoch = params.cur_epoch
params.best_train_loss = params.train_loss
def run(rank, world_size, args):
"""
Args:
rank:
It is a value between 0 and `world_size-1`, which is
passed automatically by `mp.spawn()` in :func:`main`.
The node with rank 0 is responsible for saving checkpoint.
world_size:
Number of GPUs for DDP training.
args:
The return value of get_parser().parse_args()
"""
params = get_params()
params.update(vars(args))
fix_random_seed(42)
if world_size > 1:
setup_dist(rank, world_size, params.master_port)
setup_logger(f"{params.exp_dir}/log/log-train")
logging.info("Training started")
logging.info(params)
if args.tensorboard and rank == 0:
tb_writer = SummaryWriter(log_dir=f"{params.exp_dir}/tensorboard")
else:
tb_writer = None
lexicon = Lexicon(params.lang_dir)
max_token_id = max(lexicon.tokens)
num_classes = max_token_id + 1 # +1 for the blank
device = torch.device("cpu")
if torch.cuda.is_available():
device = torch.device("cuda", rank)
graph_compiler = BpeCtcTrainingGraphCompiler(
params.lang_dir,
device=device,
sos_token="<sos/eos>",
eos_token="<sos/eos>",
)
logging.info("About to create model")
model = Conformer(
num_features=params.feature_dim,
nhead=params.nhead,
d_model=params.attention_dim,
num_classes=num_classes,
subsampling_factor=params.subsampling_factor,
num_decoder_layers=params.num_decoder_layers,
vgg_frontend=False,
use_feat_batchnorm=params.use_feat_batchnorm,
)
checkpoints = load_checkpoint_if_available(params=params, model=model)
model.to(device)
if world_size > 1:
model = DDP(model, device_ids=[rank])
optimizer = Noam(
model.parameters(),
model_size=params.attention_dim,
factor=params.lr_factor,
warm_step=params.warm_step,
weight_decay=params.weight_decay,
)
if checkpoints:
optimizer.load_state_dict(checkpoints["optimizer"])
librispeech = LibriSpeechAsrDataModule(args)
train_dl = librispeech.train_dataloaders()
valid_dl = librispeech.valid_dataloaders()
scan_pessimistic_batches_for_oom(
model=model,
train_dl=train_dl,
optimizer=optimizer,
graph_compiler=graph_compiler,
params=params,
)
for epoch in range(params.start_epoch, params.num_epochs):
train_dl.sampler.set_epoch(epoch)
cur_lr = optimizer._rate
if tb_writer is not None:
tb_writer.add_scalar(
"train/learning_rate", cur_lr, params.batch_idx_train
)
tb_writer.add_scalar("train/epoch", epoch, params.batch_idx_train)
if rank == 0:
logging.info("epoch {}, learning rate {}".format(epoch, cur_lr))
params.cur_epoch = epoch
train_one_epoch(
params=params,
model=model,
optimizer=optimizer,
graph_compiler=graph_compiler,
train_dl=train_dl,
valid_dl=valid_dl,
tb_writer=tb_writer,
world_size=world_size,
)
save_checkpoint(
params=params,
model=model,
optimizer=optimizer,
rank=rank,
)
logging.info("Done!")
if world_size > 1:
torch.distributed.barrier()
cleanup_dist()
def scan_pessimistic_batches_for_oom(
model: nn.Module,
train_dl: torch.utils.data.DataLoader,
optimizer: torch.optim.Optimizer,
graph_compiler: BpeCtcTrainingGraphCompiler,
params: AttributeDict,
):
from lhotse.dataset import find_pessimistic_batches
logging.info(
"Sanity check -- see if any of the batches in epoch 0 would cause OOM."
)
batches, crit_values = find_pessimistic_batches(train_dl.sampler)
for criterion, cuts in batches.items():
batch = train_dl.dataset[cuts]
try:
optimizer.zero_grad()
loss, _ = compute_loss(
params=params,
model=model,
batch=batch,
graph_compiler=graph_compiler,
is_training=True,
)
loss.backward()
clip_grad_norm_(model.parameters(), 5.0, 2.0)
optimizer.step()
except RuntimeError as e:
if "CUDA out of memory" in str(e):
logging.error(
"Your GPU ran out of memory with the current "
"max_duration setting. We recommend decreasing "
"max_duration and trying again.\n"
f"Failing criterion: {criterion} "
f"(={crit_values[criterion]}) ..."
)
raise
def main():
parser = get_parser()
LibriSpeechAsrDataModule.add_arguments(parser)
args = parser.parse_args()
args.exp_dir = Path(args.exp_dir)
args.lang_dir = Path(args.lang_dir)
world_size = args.world_size
assert world_size >= 1
if world_size > 1:
mp.spawn(run, args=(world_size, args), nprocs=world_size, join=True)
else:
run(rank=0, world_size=1, args=args)
torch.set_num_threads(1)
torch.set_num_interop_threads(1)
if __name__ == "__main__":
main()

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# Copyright 2021 University of Chinese Academy of Sciences (author: Han Zhu)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import math
from typing import Dict, List, Optional, Tuple
import torch
import torch.nn as nn
from label_smoothing import LabelSmoothingLoss
from subsampling import Conv2dSubsampling, VggSubsampling
from torch.nn.utils.rnn import pad_sequence
# Note: TorchScript requires Dict/List/etc. to be fully typed.
Supervisions = Dict[str, torch.Tensor]
class Transformer(nn.Module):
def __init__(
self,
num_features: int,
num_classes: int,
subsampling_factor: int = 4,
d_model: int = 256,
nhead: int = 4,
dim_feedforward: int = 2048,
num_encoder_layers: int = 12,
num_decoder_layers: int = 6,
dropout: float = 0.1,
normalize_before: bool = True,
vgg_frontend: bool = False,
use_feat_batchnorm: bool = False,
) -> None:
"""
Args:
num_features:
The input dimension of the model.
num_classes:
The output dimension of the model.
subsampling_factor:
Number of output frames is num_in_frames // subsampling_factor.
Currently, subsampling_factor MUST be 4.
d_model:
Attention dimension.
nhead:
Number of heads in multi-head attention.
Must satisfy d_model // nhead == 0.
dim_feedforward:
The output dimension of the feedforward layers in encoder/decoder.
num_encoder_layers:
Number of encoder layers.
num_decoder_layers:
Number of decoder layers.
dropout:
Dropout in encoder/decoder.
normalize_before:
If True, use pre-layer norm; False to use post-layer norm.
vgg_frontend:
True to use vgg style frontend for subsampling.
use_feat_batchnorm:
True to use batchnorm for the input layer.
"""
super().__init__()
self.use_feat_batchnorm = use_feat_batchnorm
if use_feat_batchnorm:
self.feat_batchnorm = nn.BatchNorm1d(num_features)
self.num_features = num_features
self.num_classes = num_classes
self.subsampling_factor = subsampling_factor
if subsampling_factor != 4:
raise NotImplementedError("Support only 'subsampling_factor=4'.")
# self.encoder_embed converts the input of shape (N, T, num_classes)
# to the shape (N, T//subsampling_factor, d_model).
# That is, it does two things simultaneously:
# (1) subsampling: T -> T//subsampling_factor
# (2) embedding: num_classes -> d_model
if vgg_frontend:
self.encoder_embed = VggSubsampling(num_features, d_model)
else:
self.encoder_embed = Conv2dSubsampling(num_features, d_model)
self.encoder_pos = PositionalEncoding(d_model, dropout)
encoder_layer = TransformerEncoderLayer(
d_model=d_model,
nhead=nhead,
dim_feedforward=dim_feedforward,
dropout=dropout,
normalize_before=normalize_before,
)
if normalize_before:
encoder_norm = nn.LayerNorm(d_model)
else:
encoder_norm = None
self.encoder = nn.TransformerEncoder(
encoder_layer=encoder_layer,
num_layers=num_encoder_layers,
norm=encoder_norm,
)
# TODO(fangjun): remove dropout
self.encoder_output_layer = nn.Sequential(
nn.Dropout(p=dropout), nn.Linear(d_model, num_classes)
)
if num_decoder_layers > 0:
self.decoder_num_class = (
self.num_classes
) # bpe model already has sos/eos symbol
self.decoder_embed = nn.Embedding(
num_embeddings=self.decoder_num_class, embedding_dim=d_model
)
self.decoder_pos = PositionalEncoding(d_model, dropout)
decoder_layer = TransformerDecoderLayer(
d_model=d_model,
nhead=nhead,
dim_feedforward=dim_feedforward,
dropout=dropout,
normalize_before=normalize_before,
)
if normalize_before:
decoder_norm = nn.LayerNorm(d_model)
else:
decoder_norm = None
self.decoder = nn.TransformerDecoder(
decoder_layer=decoder_layer,
num_layers=num_decoder_layers,
norm=decoder_norm,
)
self.decoder_output_layer = torch.nn.Linear(
d_model, self.decoder_num_class
)
self.decoder_criterion = LabelSmoothingLoss()
else:
self.decoder_criterion = None
def forward(
self, x: torch.Tensor, supervision: Optional[Supervisions] = None
) -> Tuple[torch.Tensor, torch.Tensor, Optional[torch.Tensor]]:
"""
Args:
x:
The input tensor. Its shape is (N, T, C).
supervision:
Supervision in lhotse format.
See https://github.com/lhotse-speech/lhotse/blob/master/lhotse/dataset/speech_recognition.py#L32 # noqa
(CAUTION: It contains length information, i.e., start and number of
frames, before subsampling)
Returns:
Return a tuple containing 3 tensors:
- CTC output for ctc decoding. Its shape is (N, T, C)
- Encoder output with shape (T, N, C). It can be used as key and
value for the decoder.
- Encoder output padding mask. It can be used as
memory_key_padding_mask for the decoder. Its shape is (N, T).
It is None if `supervision` is None.
"""
if self.use_feat_batchnorm:
x = x.permute(0, 2, 1) # (N, T, C) -> (N, C, T)
x = self.feat_batchnorm(x)
x = x.permute(0, 2, 1) # (N, C, T) -> (N, T, C)
encoder_memory, memory_key_padding_mask = self.run_encoder(
x, supervision
)
x = self.ctc_output(encoder_memory)
return x, encoder_memory, memory_key_padding_mask
def run_encoder(
self, x: torch.Tensor, supervisions: Optional[Supervisions] = None
) -> Tuple[torch.Tensor, Optional[torch.Tensor]]:
"""Run the transformer encoder.
Args:
x:
The model input. Its shape is (N, T, C).
supervisions:
Supervision in lhotse format.
See https://github.com/lhotse-speech/lhotse/blob/master/lhotse/dataset/speech_recognition.py#L32 # noqa
CAUTION: It contains length information, i.e., start and number of
frames, before subsampling
It is read directly from the batch, without any sorting. It is used
to compute the encoder padding mask, which is used as memory key
padding mask for the decoder.
Returns:
Return a tuple with two tensors:
- The encoder output, with shape (T, N, C)
- encoder padding mask, with shape (N, T).
The mask is None if `supervisions` is None.
It is used as memory key padding mask in the decoder.
"""
x = self.encoder_embed(x)
x = self.encoder_pos(x)
x = x.permute(1, 0, 2) # (N, T, C) -> (T, N, C)
mask = encoder_padding_mask(x.size(0), supervisions)
mask = mask.to(x.device) if mask is not None else None
x = self.encoder(x, src_key_padding_mask=mask) # (T, N, C)
return x, mask
def ctc_output(self, x: torch.Tensor) -> torch.Tensor:
"""
Args:
x:
The output tensor from the transformer encoder.
Its shape is (T, N, C)
Returns:
Return a tensor that can be used for CTC decoding.
Its shape is (N, T, C)
"""
x = self.encoder_output_layer(x)
x = x.permute(1, 0, 2) # (T, N, C) ->(N, T, C)
x = nn.functional.log_softmax(x, dim=-1) # (N, T, C)
return x
@torch.jit.export
def decoder_forward(
self,
memory: torch.Tensor,
memory_key_padding_mask: torch.Tensor,
token_ids: List[List[int]],
sos_id: int,
eos_id: int,
) -> torch.Tensor:
"""
Args:
memory:
It's the output of the encoder with shape (T, N, C)
memory_key_padding_mask:
The padding mask from the encoder.
token_ids:
A list-of-list IDs. Each sublist contains IDs for an utterance.
The IDs can be either phone IDs or word piece IDs.
sos_id:
sos token id
eos_id:
eos token id
Returns:
A scalar, the **sum** of label smoothing loss over utterances
in the batch without any normalization.
"""
ys_in = add_sos(token_ids, sos_id=sos_id)
ys_in = [torch.tensor(y) for y in ys_in]
ys_in_pad = pad_sequence(
ys_in, batch_first=True, padding_value=float(eos_id)
)
ys_out = add_eos(token_ids, eos_id=eos_id)
ys_out = [torch.tensor(y) for y in ys_out]
ys_out_pad = pad_sequence(
ys_out, batch_first=True, padding_value=float(-1)
)
device = memory.device
ys_in_pad = ys_in_pad.to(device)
ys_out_pad = ys_out_pad.to(device)
tgt_mask = generate_square_subsequent_mask(ys_in_pad.shape[-1]).to(
device
)
tgt_key_padding_mask = decoder_padding_mask(ys_in_pad, ignore_id=eos_id)
# TODO: Use length information to create the decoder padding mask
# We set the first column to False since the first column in ys_in_pad
# contains sos_id, which is the same as eos_id in our current setting.
tgt_key_padding_mask[:, 0] = False
tgt = self.decoder_embed(ys_in_pad) # (N, T) -> (N, T, C)
tgt = self.decoder_pos(tgt)
tgt = tgt.permute(1, 0, 2) # (N, T, C) -> (T, N, C)
pred_pad = self.decoder(
tgt=tgt,
memory=memory,
tgt_mask=tgt_mask,
tgt_key_padding_mask=tgt_key_padding_mask,
memory_key_padding_mask=memory_key_padding_mask,
) # (T, N, C)
pred_pad = pred_pad.permute(1, 0, 2) # (T, N, C) -> (N, T, C)
pred_pad = self.decoder_output_layer(pred_pad) # (N, T, C)
decoder_loss = self.decoder_criterion(pred_pad, ys_out_pad)
return decoder_loss
@torch.jit.export
def decoder_nll(
self,
memory: torch.Tensor,
memory_key_padding_mask: torch.Tensor,
token_ids: List[torch.Tensor],
sos_id: int,
eos_id: int,
) -> torch.Tensor:
"""
Args:
memory:
It's the output of the encoder with shape (T, N, C)
memory_key_padding_mask:
The padding mask from the encoder.
token_ids:
A list-of-list IDs (e.g., word piece IDs).
Each sublist represents an utterance.
sos_id:
The token ID for SOS.
eos_id:
The token ID for EOS.
Returns:
A 2-D tensor of shape (len(token_ids), max_token_length)
representing the cross entropy loss (i.e., negative log-likelihood).
"""
# The common part between this function and decoder_forward could be
# extracted as a separate function.
if isinstance(token_ids[0], torch.Tensor):
# This branch is executed by torchscript in C++.
# See https://github.com/k2-fsa/k2/pull/870
# https://github.com/k2-fsa/k2/blob/3c1c18400060415b141ccea0115fd4bf0ad6234e/k2/torch/bin/attention_rescore.cu#L286
token_ids = [tolist(t) for t in token_ids]
ys_in = add_sos(token_ids, sos_id=sos_id)
ys_in = [torch.tensor(y) for y in ys_in]
ys_in_pad = pad_sequence(
ys_in, batch_first=True, padding_value=float(eos_id)
)
ys_out = add_eos(token_ids, eos_id=eos_id)
ys_out = [torch.tensor(y) for y in ys_out]
ys_out_pad = pad_sequence(
ys_out, batch_first=True, padding_value=float(-1)
)
device = memory.device
ys_in_pad = ys_in_pad.to(device, dtype=torch.int64)
ys_out_pad = ys_out_pad.to(device, dtype=torch.int64)
tgt_mask = generate_square_subsequent_mask(ys_in_pad.shape[-1]).to(
device
)
tgt_key_padding_mask = decoder_padding_mask(ys_in_pad, ignore_id=eos_id)
# TODO: Use length information to create the decoder padding mask
# We set the first column to False since the first column in ys_in_pad
# contains sos_id, which is the same as eos_id in our current setting.
tgt_key_padding_mask[:, 0] = False
tgt = self.decoder_embed(ys_in_pad) # (B, T) -> (B, T, F)
tgt = self.decoder_pos(tgt)
tgt = tgt.permute(1, 0, 2) # (B, T, F) -> (T, B, F)
pred_pad = self.decoder(
tgt=tgt,
memory=memory,
tgt_mask=tgt_mask,
tgt_key_padding_mask=tgt_key_padding_mask,
memory_key_padding_mask=memory_key_padding_mask,
) # (T, B, F)
pred_pad = pred_pad.permute(1, 0, 2) # (T, B, F) -> (B, T, F)
pred_pad = self.decoder_output_layer(pred_pad) # (B, T, F)
# nll: negative log-likelihood
nll = torch.nn.functional.cross_entropy(
pred_pad.view(-1, self.decoder_num_class),
ys_out_pad.view(-1),
ignore_index=-1,
reduction="none",
)
nll = nll.view(pred_pad.shape[0], -1)
return nll
class TransformerEncoderLayer(nn.Module):
"""
Modified from torch.nn.TransformerEncoderLayer.
Add support of normalize_before,
i.e., use layer_norm before the first block.
Args:
d_model:
the number of expected features in the input (required).
nhead:
the number of heads in the multiheadattention models (required).
dim_feedforward:
the dimension of the feedforward network model (default=2048).
dropout:
the dropout value (default=0.1).
activation:
the activation function of intermediate layer, relu or
gelu (default=relu).
normalize_before:
whether to use layer_norm before the first block.
Examples::
>>> encoder_layer = TransformerEncoderLayer(d_model=512, nhead=8)
>>> src = torch.rand(10, 32, 512)
>>> out = encoder_layer(src)
"""
def __init__(
self,
d_model: int,
nhead: int,
dim_feedforward: int = 2048,
dropout: float = 0.1,
activation: str = "relu",
normalize_before: bool = True,
) -> None:
super(TransformerEncoderLayer, self).__init__()
self.self_attn = nn.MultiheadAttention(d_model, nhead, dropout=0.0)
# Implementation of Feedforward model
self.linear1 = nn.Linear(d_model, dim_feedforward)
self.dropout = nn.Dropout(dropout)
self.linear2 = nn.Linear(dim_feedforward, d_model)
self.norm1 = nn.LayerNorm(d_model)
self.norm2 = nn.LayerNorm(d_model)
self.dropout1 = nn.Dropout(dropout)
self.dropout2 = nn.Dropout(dropout)
self.activation = _get_activation_fn(activation)
self.normalize_before = normalize_before
def __setstate__(self, state):
if "activation" not in state:
state["activation"] = nn.functional.relu
super(TransformerEncoderLayer, self).__setstate__(state)
def forward(
self,
src: torch.Tensor,
src_mask: Optional[torch.Tensor] = None,
src_key_padding_mask: Optional[torch.Tensor] = None,
) -> torch.Tensor:
"""
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:
src: (S, N, E).
src_mask: (S, S).
src_key_padding_mask: (N, S).
S is the source sequence length, T is the target sequence length,
N is the batch size, E is the feature number
"""
residual = src
if self.normalize_before:
src = self.norm1(src)
src2 = self.self_attn(
src,
src,
src,
attn_mask=src_mask,
key_padding_mask=src_key_padding_mask,
)[0]
src = residual + self.dropout1(src2)
if not self.normalize_before:
src = self.norm1(src)
residual = src
if self.normalize_before:
src = self.norm2(src)
src2 = self.linear2(self.dropout(self.activation(self.linear1(src))))
src = residual + self.dropout2(src2)
if not self.normalize_before:
src = self.norm2(src)
return src
class TransformerDecoderLayer(nn.Module):
"""
Modified from torch.nn.TransformerDecoderLayer.
Add support of normalize_before,
i.e., use layer_norm before the first block.
Args:
d_model:
the number of expected features in the input (required).
nhead:
the number of heads in the multiheadattention models (required).
dim_feedforward:
the dimension of the feedforward network model (default=2048).
dropout:
the dropout value (default=0.1).
activation:
the activation function of intermediate layer, relu or
gelu (default=relu).
Examples::
>>> decoder_layer = nn.TransformerDecoderLayer(d_model=512, nhead=8)
>>> memory = torch.rand(10, 32, 512)
>>> tgt = torch.rand(20, 32, 512)
>>> out = decoder_layer(tgt, memory)
"""
def __init__(
self,
d_model: int,
nhead: int,
dim_feedforward: int = 2048,
dropout: float = 0.1,
activation: str = "relu",
normalize_before: bool = True,
) -> None:
super(TransformerDecoderLayer, self).__init__()
self.self_attn = nn.MultiheadAttention(d_model, nhead, dropout=0.0)
self.src_attn = nn.MultiheadAttention(d_model, nhead, dropout=0.0)
# Implementation of Feedforward model
self.linear1 = nn.Linear(d_model, dim_feedforward)
self.dropout = nn.Dropout(dropout)
self.linear2 = nn.Linear(dim_feedforward, d_model)
self.norm1 = nn.LayerNorm(d_model)
self.norm2 = nn.LayerNorm(d_model)
self.norm3 = nn.LayerNorm(d_model)
self.dropout1 = nn.Dropout(dropout)
self.dropout2 = nn.Dropout(dropout)
self.dropout3 = nn.Dropout(dropout)
self.activation = _get_activation_fn(activation)
self.normalize_before = normalize_before
def __setstate__(self, state):
if "activation" not in state:
state["activation"] = nn.functional.relu
super(TransformerDecoderLayer, self).__setstate__(state)
def forward(
self,
tgt: torch.Tensor,
memory: torch.Tensor,
tgt_mask: Optional[torch.Tensor] = None,
memory_mask: Optional[torch.Tensor] = None,
tgt_key_padding_mask: Optional[torch.Tensor] = None,
memory_key_padding_mask: Optional[torch.Tensor] = None,
) -> torch.Tensor:
"""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:
tgt: (T, N, E).
memory: (S, N, E).
tgt_mask: (T, T).
memory_mask: (T, S).
tgt_key_padding_mask: (N, T).
memory_key_padding_mask: (N, S).
S is the source sequence length, T is the target sequence length,
N is the batch size, E is the feature number
"""
residual = tgt
if self.normalize_before:
tgt = self.norm1(tgt)
tgt2 = self.self_attn(
tgt,
tgt,
tgt,
attn_mask=tgt_mask,
key_padding_mask=tgt_key_padding_mask,
)[0]
tgt = residual + self.dropout1(tgt2)
if not self.normalize_before:
tgt = self.norm1(tgt)
residual = tgt
if self.normalize_before:
tgt = self.norm2(tgt)
tgt2 = self.src_attn(
tgt,
memory,
memory,
attn_mask=memory_mask,
key_padding_mask=memory_key_padding_mask,
)[0]
tgt = residual + self.dropout2(tgt2)
if not self.normalize_before:
tgt = self.norm2(tgt)
residual = tgt
if self.normalize_before:
tgt = self.norm3(tgt)
tgt2 = self.linear2(self.dropout(self.activation(self.linear1(tgt))))
tgt = residual + self.dropout3(tgt2)
if not self.normalize_before:
tgt = self.norm3(tgt)
return tgt
def _get_activation_fn(activation: str):
if activation == "relu":
return nn.functional.relu
elif activation == "gelu":
return nn.functional.gelu
raise RuntimeError(
"activation should be relu/gelu, not {}".format(activation)
)
class PositionalEncoding(nn.Module):
"""This class implements the positional encoding
proposed in the following paper:
- Attention Is All You Need: https://arxiv.org/pdf/1706.03762.pdf
PE(pos, 2i) = sin(pos / (10000^(2i/d_modle))
PE(pos, 2i+1) = cos(pos / (10000^(2i/d_modle))
Note::
1 / (10000^(2i/d_model)) = exp(-log(10000^(2i/d_model)))
= exp(-1* 2i / d_model * log(100000))
= exp(2i * -(log(10000) / d_model))
"""
def __init__(self, d_model: int, dropout: float = 0.1) -> None:
"""
Args:
d_model:
Embedding dimension.
dropout:
Dropout probability to be applied to the output of this module.
"""
super().__init__()
self.d_model = d_model
self.xscale = math.sqrt(self.d_model)
self.dropout = nn.Dropout(p=dropout)
# not doing: self.pe = None because of errors thrown by torchscript
self.pe = torch.zeros(1, 0, self.d_model, dtype=torch.float32)
def extend_pe(self, x: torch.Tensor) -> None:
"""Extend the time t in the positional encoding if required.
The shape of `self.pe` is (1, T1, d_model). The shape of the input x
is (N, T, d_model). If T > T1, then we change the shape of self.pe
to (N, T, d_model). Otherwise, nothing is done.
Args:
x:
It is a tensor of shape (N, T, C).
Returns:
Return None.
"""
if self.pe is not None:
if self.pe.size(1) >= x.size(1):
self.pe = self.pe.to(dtype=x.dtype, device=x.device)
return
pe = torch.zeros(x.size(1), self.d_model, dtype=torch.float32)
position = torch.arange(0, x.size(1), dtype=torch.float32).unsqueeze(1)
div_term = torch.exp(
torch.arange(0, self.d_model, 2, dtype=torch.float32)
* -(math.log(10000.0) / self.d_model)
)
pe[:, 0::2] = torch.sin(position * div_term)
pe[:, 1::2] = torch.cos(position * div_term)
pe = pe.unsqueeze(0)
# Now pe is of shape (1, T, d_model), where T is x.size(1)
self.pe = pe.to(device=x.device, dtype=x.dtype)
def forward(self, x: torch.Tensor) -> torch.Tensor:
"""
Add positional encoding.
Args:
x:
Its shape is (N, T, C)
Returns:
Return a tensor of shape (N, T, C)
"""
self.extend_pe(x)
x = x * self.xscale + self.pe[:, : x.size(1), :]
return self.dropout(x)
class Noam(object):
"""
Implements Noam optimizer.
Proposed in
"Attention Is All You Need", https://arxiv.org/pdf/1706.03762.pdf
Modified from
https://github.com/espnet/espnet/blob/master/espnet/nets/pytorch_backend/transformer/optimizer.py # noqa
Args:
params:
iterable of parameters to optimize or dicts defining parameter groups
model_size:
attention dimension of the transformer model
factor:
learning rate factor
warm_step:
warmup steps
"""
def __init__(
self,
params,
model_size: int = 256,
factor: float = 10.0,
warm_step: int = 25000,
weight_decay=0,
) -> None:
"""Construct an Noam object."""
self.optimizer = torch.optim.Adam(
params, lr=0, betas=(0.9, 0.98), eps=1e-9, weight_decay=weight_decay
)
self._step = 0
self.warmup = warm_step
self.factor = factor
self.model_size = model_size
self._rate = 0
@property
def param_groups(self):
"""Return param_groups."""
return self.optimizer.param_groups
def step(self):
"""Update parameters and rate."""
self._step += 1
rate = self.rate()
for p in self.optimizer.param_groups:
p["lr"] = rate
self._rate = rate
self.optimizer.step()
def rate(self, step=None):
"""Implement `lrate` above."""
if step is None:
step = self._step
return (
self.factor
* self.model_size ** (-0.5)
* min(step ** (-0.5), step * self.warmup ** (-1.5))
)
def zero_grad(self):
"""Reset gradient."""
self.optimizer.zero_grad()
def state_dict(self):
"""Return state_dict."""
return {
"_step": self._step,
"warmup": self.warmup,
"factor": self.factor,
"model_size": self.model_size,
"_rate": self._rate,
"optimizer": self.optimizer.state_dict(),
}
def load_state_dict(self, state_dict):
"""Load state_dict."""
for key, value in state_dict.items():
if key == "optimizer":
self.optimizer.load_state_dict(state_dict["optimizer"])
else:
setattr(self, key, value)
def encoder_padding_mask(
max_len: int, supervisions: Optional[Supervisions] = None
) -> Optional[torch.Tensor]:
"""Make mask tensor containing indexes of padded part.
TODO::
This function **assumes** that the model uses
a subsampling factor of 4. We should remove that
assumption later.
Args:
max_len:
Maximum length of input features.
CAUTION: It is the length after subsampling.
supervisions:
Supervision in lhotse format.
See https://github.com/lhotse-speech/lhotse/blob/master/lhotse/dataset/speech_recognition.py#L32 # noqa
(CAUTION: It contains length information, i.e., start and number of
frames, before subsampling)
Returns:
Tensor: Mask tensor of dimension (batch_size, input_length),
True denote the masked indices.
"""
if supervisions is None:
return None
supervision_segments = torch.stack(
(
supervisions["sequence_idx"],
supervisions["start_frame"],
supervisions["num_frames"],
),
1,
).to(torch.int32)
lengths = [
0 for _ in range(int(supervision_segments[:, 0].max().item()) + 1)
]
for idx in range(supervision_segments.size(0)):
# Note: TorchScript doesn't allow to unpack tensors as tuples
sequence_idx = supervision_segments[idx, 0].item()
start_frame = supervision_segments[idx, 1].item()
num_frames = supervision_segments[idx, 2].item()
lengths[sequence_idx] = start_frame + num_frames
lengths = [((i - 1) // 2 - 1) // 2 for i in lengths]
bs = int(len(lengths))
seq_range = torch.arange(0, max_len, dtype=torch.int64)
seq_range_expand = seq_range.unsqueeze(0).expand(bs, max_len)
# Note: TorchScript doesn't implement Tensor.new()
seq_length_expand = torch.tensor(
lengths, device=seq_range_expand.device, dtype=seq_range_expand.dtype
).unsqueeze(-1)
mask = seq_range_expand >= seq_length_expand
return mask
def decoder_padding_mask(
ys_pad: torch.Tensor, ignore_id: int = -1
) -> torch.Tensor:
"""Generate a length mask for input.
The masked position are filled with True,
Unmasked positions are filled with False.
Args:
ys_pad:
padded tensor of dimension (batch_size, input_length).
ignore_id:
the ignored number (the padding number) in ys_pad
Returns:
Tensor:
a bool tensor of the same shape as the input tensor.
"""
ys_mask = ys_pad == ignore_id
return ys_mask
def generate_square_subsequent_mask(sz: int) -> torch.Tensor:
"""Generate a square mask for the sequence. The masked positions are
filled with float('-inf'). Unmasked positions are filled with float(0.0).
The mask can be used for masked self-attention.
For instance, if sz is 3, it returns::
tensor([[0., -inf, -inf],
[0., 0., -inf],
[0., 0., 0]])
Args:
sz: mask size
Returns:
A square mask of dimension (sz, sz)
"""
mask = (torch.triu(torch.ones(sz, sz)) == 1).transpose(0, 1)
mask = (
mask.float()
.masked_fill(mask == 0, float("-inf"))
.masked_fill(mask == 1, float(0.0))
)
return mask
def add_sos(token_ids: List[List[int]], sos_id: int) -> List[List[int]]:
"""Prepend sos_id to each utterance.
Args:
token_ids:
A list-of-list of token IDs. Each sublist contains
token IDs (e.g., word piece IDs) of an utterance.
sos_id:
The ID of the SOS token.
Return:
Return a new list-of-list, where each sublist starts
with SOS ID.
"""
return [[sos_id] + utt for utt in token_ids]
def add_eos(token_ids: List[List[int]], eos_id: int) -> List[List[int]]:
"""Append eos_id to each utterance.
Args:
token_ids:
A list-of-list of token IDs. Each sublist contains
token IDs (e.g., word piece IDs) of an utterance.
eos_id:
The ID of the EOS token.
Return:
Return a new list-of-list, where each sublist ends
with EOS ID.
"""
return [utt + [eos_id] for utt in token_ids]
def tolist(t: torch.Tensor) -> List[int]:
"""Used by jit"""
return torch.jit.annotate(List[int], t.tolist())