Use similar number of parameters as conformer encoder.

This commit is contained in:
Fangjun Kuang 2021-12-28 11:09:43 +08:00
parent ec083e93d8
commit 3c89734b79
5 changed files with 28 additions and 111 deletions

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@ -13,7 +13,7 @@ The following table lists the differences among them.
|------------------------|-----------|--------------------|
| `transducer` | Conformer | LSTM |
| `transducer_stateless` | Conformer | Embedding + Conv1d |
| `transducer_lstm ` | LSTM | LSTM |
| `transducer_lstm ` | LSTM | Embedding + Conv1d |
The decoder in `transducer_stateless` is modified from the paper
[Rnn-Transducer with Stateless Prediction Network](https://ieeexplore.ieee.org/document/9054419/).

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@ -32,7 +32,7 @@ Usage:
--exp-dir ./transducer_lstm/exp \
--max-duration 100 \
--decoding-method beam_search \
--beam-size 8
--beam-size 4
"""
@ -70,14 +70,14 @@ def get_parser():
parser.add_argument(
"--epoch",
type=int,
default=77,
default=29,
help="It specifies the checkpoint to use for decoding."
"Note: Epoch counts from 0.",
)
parser.add_argument(
"--avg",
type=int,
default=55,
default=13,
help="Number of checkpoints to average. Automatically select "
"consecutive checkpoints before the checkpoint specified by "
"'--epoch'. ",
@ -110,7 +110,7 @@ def get_parser():
parser.add_argument(
"--beam-size",
type=int,
default=5,
default=4,
help="Used only when --decoding-method is beam_search",
)
@ -122,6 +122,13 @@ def get_parser():
"2 means tri-gram",
)
parser.add_argument(
"--max-sym-per-frame",
type=int,
default=3,
help="Maximum number of symbols per frame",
)
return parser
@ -132,8 +139,8 @@ def get_params() -> AttributeDict:
"feature_dim": 80,
"encoder_out_dim": 512,
"subsampling_factor": 4,
"encoder_hidden_size": 2048,
"num_encoder_layers": 6,
"encoder_hidden_size": 1024,
"num_encoder_layers": 7,
"proj_size": 512,
"vgg_frontend": False,
"env_info": get_env_info(),
@ -237,7 +244,11 @@ def decode_one_batch(
encoder_out_i = encoder_out[i:i+1, :encoder_out_lens[i]]
# fmt: on
if params.decoding_method == "greedy_search":
hyp = greedy_search(model=model, encoder_out=encoder_out_i)
hyp = greedy_search(
model=model,
encoder_out=encoder_out_i,
max_sym_per_frame=params.max_sym_per_frame,
)
elif params.decoding_method == "beam_search":
hyp = beam_search(
model=model, encoder_out=encoder_out_i, beam=params.beam_size
@ -381,6 +392,9 @@ def main():
params.suffix = f"epoch-{params.epoch}-avg-{params.avg}"
if params.decoding_method == "beam_search":
params.suffix += f"-beam-{params.beam_size}"
else:
params.suffix += f"-context-{params.context_size}"
params.suffix += f"-max-sym-per-frame-{params.max_sym_per_frame}"
setup_logger(f"{params.res_dir}/log-decode-{params.suffix}")
logging.info("Decoding started")

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@ -1,98 +0,0 @@
# Copyright 2021 Xiaomi Corp. (authors: Fangjun Kuang)
#
# 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 torch
import torch.nn as nn
import torch.nn.functional as F
class Decoder(nn.Module):
"""This class modifies the stateless decoder from the following paper:
RNN-transducer with stateless prediction network
https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9054419
It removes the recurrent connection from the decoder, i.e., the prediction
network. Different from the above paper, it adds an extra Conv1d
right after the embedding layer.
TODO: Implement https://arxiv.org/pdf/2109.07513.pdf
"""
def __init__(
self,
vocab_size: int,
embedding_dim: int,
blank_id: int,
context_size: int,
):
"""
Args:
vocab_size:
Number of tokens of the modeling unit including blank.
embedding_dim:
Dimension of the input embedding.
blank_id:
The ID of the blank symbol.
context_size:
Number of previous words to use to predict the next word.
1 means bigram; 2 means trigram. n means (n+1)-gram.
"""
super().__init__()
self.embedding = nn.Embedding(
num_embeddings=vocab_size,
embedding_dim=embedding_dim,
padding_idx=blank_id,
)
self.blank_id = blank_id
assert context_size >= 1, context_size
self.context_size = context_size
if context_size > 1:
self.conv = nn.Conv1d(
in_channels=embedding_dim,
out_channels=embedding_dim,
kernel_size=context_size,
padding=0,
groups=embedding_dim,
bias=False,
)
def forward(self, y: torch.Tensor, need_pad: bool = True) -> torch.Tensor:
"""
Args:
y:
A 2-D tensor of shape (N, U) with blank prepended.
need_pad:
True to left pad the input. Should be True during training.
False to not pad the input. Should be False during inference.
Returns:
Return a tensor of shape (N, U, embedding_dim).
"""
embeding_out = self.embedding(y)
if self.context_size > 1:
embeding_out = embeding_out.permute(0, 2, 1)
if need_pad is True:
embeding_out = F.pad(
embeding_out, pad=(self.context_size - 1, 0)
)
else:
# During inference time, there is no need to do extra padding
# as we only need one output
assert embeding_out.size(-1) == self.context_size
embeding_out = self.conv(embeding_out)
embeding_out = embeding_out.permute(0, 2, 1)
return embeding_out

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@ -0,0 +1 @@
../transducer_stateless/decoder.py

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@ -49,14 +49,14 @@ class Transducer(nn.Module):
decoder:
It is the prediction network in the paper. Its input shape
is (N, U) and its output shape is (N, U, C). It should contain
one attributes `blank_id`.
one attribute: `blank_id`.
joiner:
It has two inputs with shapes: (N, T, C) and (N, U, C). Its
output shape is (N, T, U, C). Note that its output contains
unnormalized probs, i.e., not processed by log-softmax.
"""
super().__init__()
assert isinstance(encoder, EncoderInterface)
assert isinstance(encoder, EncoderInterface), type(encoder)
assert hasattr(decoder, "blank_id")
self.encoder = encoder
@ -100,7 +100,7 @@ class Transducer(nn.Module):
sos_y_padded = sos_y.pad(mode="constant", padding_value=blank_id)
decoder_out, _ = self.decoder(sos_y_padded)
decoder_out = self.decoder(sos_y_padded)
logits = self.joiner(encoder_out, decoder_out)

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@ -200,8 +200,8 @@ def get_params() -> AttributeDict:
"feature_dim": 80,
"encoder_out_dim": 512,
"subsampling_factor": 4,
"encoder_hidden_size": 2048,
"num_encoder_layers": 6,
"encoder_hidden_size": 1024,
"num_encoder_layers": 7,
"proj_size": 512,
"vgg_frontend": False,
# parameters for Noam