Add BPE decoding results.

This commit is contained in:
Fangjun Kuang 2021-07-27 17:38:47 +08:00
parent 4ccae509d3
commit f65854cca5
5 changed files with 479 additions and 39 deletions

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@ -2,3 +2,120 @@
Run `./prepare.sh` to prepare the data.
Run `./xxx_train.py` (to be added) to train a model.
## Conformer-CTC
Results of the pre-trained model from
`<https://huggingface.co/GuoLiyong/snowfall_bpe_model/tree/main/exp-duration-200-feat_batchnorm-bpe-lrfactor5.0-conformer-512-8-noam>`
are given below
### HLG - no LM rescoring
(output beam size is 8)
#### 1-best decoding
```
[test-clean-no_rescore] %WER 3.15% [1656 / 52576, 127 ins, 377 del, 1152 sub ]
[test-other-no_rescore] %WER 7.03% [3682 / 52343, 220 ins, 1024 del, 2438 sub ]
```
#### n-best decoding
For n=100,
```
[test-clean-no_rescore-100] %WER 3.15% [1656 / 52576, 127 ins, 377 del, 1152 sub ]
[test-other-no_rescore-100] %WER 7.14% [3737 / 52343, 275 ins, 1020 del, 2442 sub ]
```
For n=200,
```
[test-clean-no_rescore-200] %WER 3.16% [1660 / 52576, 125 ins, 378 del, 1157 sub ]
[test-other-no_rescore-200] %WER 7.04% [3684 / 52343, 228 ins, 1012 del, 2444 sub ]
```
### HLG - with LM rescoring
#### Whole lattice rescoring
```
[test-clean-lm_scale_0.8] %WER 2.77% [1456 / 52576, 150 ins, 210 del, 1096 sub ]
[test-other-lm_scale_0.8] %WER 6.23% [3262 / 52343, 246 ins, 635 del, 2381 sub ]
```
WERs of different LM scales are:
```
For test-clean, WER of different settings are:
lm_scale_0.8 2.77 best for test-clean
lm_scale_0.9 2.87
lm_scale_1.0 3.06
lm_scale_1.1 3.34
lm_scale_1.2 3.71
lm_scale_1.3 4.18
lm_scale_1.4 4.8
lm_scale_1.5 5.48
lm_scale_1.6 6.08
lm_scale_1.7 6.79
lm_scale_1.8 7.49
lm_scale_1.9 8.14
lm_scale_2.0 8.82
For test-other, WER of different settings are:
lm_scale_0.8 6.23 best for test-other
lm_scale_0.9 6.37
lm_scale_1.0 6.62
lm_scale_1.1 6.99
lm_scale_1.2 7.46
lm_scale_1.3 8.13
lm_scale_1.4 8.84
lm_scale_1.5 9.61
lm_scale_1.6 10.32
lm_scale_1.7 11.17
lm_scale_1.8 12.12
lm_scale_1.9 12.93
lm_scale_2.0 13.77
```
#### n-best LM rescoring
n = 100
```
[test-clean-lm_scale_0.8] %WER 2.79% [1469 / 52576, 149 ins, 212 del, 1108 sub ]
[test-other-lm_scale_0.8] %WER 6.36% [3329 / 52343, 259 ins, 666 del, 2404 sub ]
```
WERs of different LM scales are:
```
For test-clean, WER of different settings are:
lm_scale_0.8 2.79 best for test-clean
lm_scale_0.9 2.89
lm_scale_1.0 3.03
lm_scale_1.1 3.28
lm_scale_1.2 3.52
lm_scale_1.3 3.78
lm_scale_1.4 4.04
lm_scale_1.5 4.24
lm_scale_1.6 4.45
lm_scale_1.7 4.58
lm_scale_1.8 4.7
lm_scale_1.9 4.8
lm_scale_2.0 4.92
For test-other, WER of different settings are:
lm_scale_0.8 6.36 best for test-other
lm_scale_0.9 6.45
lm_scale_1.0 6.64
lm_scale_1.1 6.92
lm_scale_1.2 7.25
lm_scale_1.3 7.59
lm_scale_1.4 7.88
lm_scale_1.5 8.13
lm_scale_1.6 8.36
lm_scale_1.7 8.54
lm_scale_1.8 8.71
lm_scale_1.9 8.88
lm_scale_2.0 9.02
```

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@ -6,13 +6,25 @@
import argparse
import logging
from collections import defaultdict
from pathlib import Path
from typing import Dict, List, Optional, Tuple
import k2
import torch
import torch.nn as nn
from conformer import Conformer
from icefall.checkpoint import average_checkpoints, load_checkpoint
from icefall.dataset.librispeech import LibriSpeechAsrDataModule
from icefall.decode import (
get_lattice,
nbest_decoding,
one_best_decoding,
rescore_with_n_best_list,
rescore_with_whole_lattice,
)
from icefall.lexicon import Lexicon
from icefall.utils import (
AttributeDict,
get_texts,
@ -22,40 +34,6 @@ from icefall.utils import (
)
def get_params() -> AttributeDict:
params = AttributeDict(
{
"exp_dir": Path("conformer_ctc/exp"),
"lang_dir": Path("data/lang/bpe"),
"lm_dir": Path("data/lm"),
"feature_dim": 80,
"nhead": 8,
"attention_dim": 512,
"num_classes": 5000,
"subsampling_factor": 4,
"num_decoder_layers": 6,
"vgg_frontend": False,
"is_espnet_structure": True,
"mmi_loss": False,
"use_feat_batchnorm": True,
"search_beam": 20,
"output_beam": 5,
"min_active_states": 30,
"max_active_states": 10000,
"use_double_scores": True,
# Possible values for method:
# - 1best
# - nbest
# - nbest-rescoring
# - whole-lattice-rescoring
"method": "whole-lattice-rescoring",
# num_paths is used when method is "nbest" and "nbest-rescoring"
"num_paths": 30,
}
)
return params
def get_parser():
parser = argparse.ArgumentParser(
formatter_class=argparse.ArgumentDefaultsHelpFormatter
@ -79,6 +57,270 @@ def get_parser():
return parser
def get_params() -> AttributeDict:
params = AttributeDict(
{
"exp_dir": Path("conformer_ctc/exp"),
"lang_dir": Path("data/lang/bpe"),
"lm_dir": Path("data/lm"),
"feature_dim": 80,
"nhead": 8,
"attention_dim": 512,
"subsampling_factor": 4,
"num_decoder_layers": 6,
"vgg_frontend": False,
"is_espnet_structure": True,
"mmi_loss": False,
"use_feat_batchnorm": True,
"search_beam": 20,
"output_beam": 8,
"min_active_states": 30,
"max_active_states": 10000,
"use_double_scores": True,
# Possible values for method:
# - 1best
# - nbest
# - nbest-rescoring
# - whole-lattice-rescoring
"method": "nbest-rescoring",
# num_paths is used when method is "nbest" and "nbest-rescoring"
"num_paths": 100,
}
)
return params
def decode_one_batch(
params: AttributeDict,
model: nn.Module,
HLG: k2.Fsa,
batch: dict,
lexicon: Lexicon,
G: Optional[k2.Fsa] = None,
) -> Dict[str, List[List[int]]]:
"""Decode one batch and return the result in a dict. The dict has the
following format:
- key: It indicates the setting used for decoding. For example,
if no rescoring is used, the key is the string `no_rescore`.
If LM rescoring is used, the key is the string `lm_scale_xxx`,
where `xxx` is the value of `lm_scale`. An example key is
`lm_scale_0.7`
- value: It contains the decoding result. `len(value)` equals to
batch size. `value[i]` is the decoding result for the i-th
utterance in the given batch.
Args:
params:
It's the return value of :func:`get_params`.
- params.method is "1best", it uses 1best decoding without LM rescoring.
- params.method is "nbest", it uses nbest decoding without LM rescoring.
- params.method is "nbest-rescoring", it uses nbest LM rescoring.
- params.method is "whole-lattice-rescoring", it uses whole lattice LM
rescoring.
model:
The neural model.
HLG:
The decoding graph.
batch:
It is the return value from iterating
`lhotse.dataset.K2SpeechRecognitionDataset`. See its documentation
for the format of the `batch`.
lexicon:
It contains word symbol table.
G:
An LM. It is not None when params.method is "nbest-rescoring"
or "whole-lattice-rescoring". In general, the G in HLG
is a 3-gram LM, while this G is a 4-gram LM.
Returns:
Return the decoding result. See above description for the format of
the returned dict.
"""
device = HLG.device
feature = batch["inputs"]
assert feature.ndim == 3
feature = feature.to(device)
# at entry, feature is [N, T, C]
feature = feature.permute(0, 2, 1) # now feature is [N, C, T]
supervisions = batch["supervisions"]
nnet_output, encoder_memory, memory_mask = model(feature, supervisions)
# nnet_output is [N, C, T]
nnet_output = nnet_output.permute(0, 2, 1)
# now nnet_output is [N, T, C]
supervision_segments = torch.stack(
(
supervisions["sequence_idx"],
supervisions["start_frame"] // params.subsampling_factor,
supervisions["num_frames"] // params.subsampling_factor,
),
1,
).to(torch.int32)
lattice = get_lattice(
nnet_output=nnet_output,
HLG=HLG,
supervision_segments=supervision_segments,
search_beam=params.search_beam,
output_beam=params.output_beam,
min_active_states=params.min_active_states,
max_active_states=params.max_active_states,
subsampling_factor=params.subsampling_factor,
)
if params.method in ["1best", "nbest"]:
if params.method == "1best":
best_path = one_best_decoding(
lattice=lattice, use_double_scores=params.use_double_scores
)
key = "no_rescore"
else:
best_path = nbest_decoding(
lattice=lattice,
num_paths=params.num_paths,
use_double_scores=params.use_double_scores,
)
key = f"no_rescore-{params.num_paths}"
hyps = get_texts(best_path)
hyps = [[lexicon.words[i] for i in ids] for ids in hyps]
return {key: hyps}
assert params.method in ["nbest-rescoring", "whole-lattice-rescoring"]
lm_scale_list = [0.8, 0.9, 1.0, 1.1, 1.2, 1.3]
lm_scale_list += [1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0]
if params.method == "nbest-rescoring":
best_path_dict = rescore_with_n_best_list(
lattice=lattice,
G=G,
num_paths=params.num_paths,
lm_scale_list=lm_scale_list,
)
else:
best_path_dict = rescore_with_whole_lattice(
lattice=lattice, G_with_epsilon_loops=G, lm_scale_list=lm_scale_list
)
ans = dict()
for lm_scale_str, best_path in best_path_dict.items():
hyps = get_texts(best_path)
hyps = [[lexicon.words[i] for i in ids] for ids in hyps]
ans[lm_scale_str] = hyps
return ans
def decode_dataset(
dl: torch.utils.data.DataLoader,
params: AttributeDict,
model: nn.Module,
HLG: k2.Fsa,
lexicon: Lexicon,
G: Optional[k2.Fsa] = None,
) -> Dict[str, List[Tuple[List[int], List[int]]]]:
"""Decode dataset.
Args:
dl:
PyTorch's dataloader containing the dataset to decode.
params:
It is returned by :func:`get_params`.
model:
The neural model.
HLG:
The decoding graph.
lexicon:
It contains word symbol table.
G:
An LM. It is not None when params.method is "nbest-rescoring"
or "whole-lattice-rescoring". In general, the G in HLG
is a 3-gram LM, while this G is a 4-gram LM.
Returns:
Return a dict, whose key may be "no-rescore" if no LM rescoring
is used, or it may be "lm_scale_0.7" if LM rescoring is used.
Its value is a list of tuples. Each tuple contains two elements:
The first is the reference transcript, and the second is the
predicted result.
"""
results = []
num_cuts = 0
tot_num_cuts = len(dl.dataset.cuts)
results = defaultdict(list)
for batch_idx, batch in enumerate(dl):
texts = batch["supervisions"]["text"]
hyps_dict = decode_one_batch(
params=params,
model=model,
HLG=HLG,
batch=batch,
lexicon=lexicon,
G=G,
)
for lm_scale, hyps in hyps_dict.items():
this_batch = []
assert len(hyps) == len(texts)
for hyp_words, ref_text in zip(hyps, texts):
ref_words = ref_text.split()
this_batch.append((ref_words, hyp_words))
results[lm_scale].extend(this_batch)
num_cuts += len(batch["supervisions"]["text"])
if batch_idx % 100 == 0:
logging.info(
f"batch {batch_idx}, cuts processed until now is "
f"{num_cuts}/{tot_num_cuts} "
f"({float(num_cuts)/tot_num_cuts*100:.6f}%)"
)
return results
def save_results(
params: AttributeDict,
test_set_name: str,
results_dict: Dict[str, List[Tuple[List[int], List[int]]]],
):
test_set_wers = dict()
for key, results in results_dict.items():
recog_path = params.exp_dir / f"recogs-{test_set_name}-{key}.txt"
store_transcripts(filename=recog_path, texts=results)
logging.info(f"The transcripts are stored in {recog_path}")
# The following prints out WERs, per-word error statistics and aligned
# ref/hyp pairs.
errs_filename = params.exp_dir / f"errs-{test_set_name}-{key}.txt"
with open(errs_filename, "w") as f:
wer = write_error_stats(f, f"{test_set_name}-{key}", results)
test_set_wers[key] = wer
logging.info("Wrote detailed error stats to {}".format(errs_filename))
test_set_wers = sorted(test_set_wers.items(), key=lambda x: x[1])
errs_info = params.exp_dir / f"wer-summary-{test_set_name}.txt"
with open(errs_info, "w") as f:
print("settings\tWER", file=f)
for key, val in test_set_wers:
print("{}\t{}".format(key, val), file=f)
s = "\nFor {}, WER of different settings are:\n".format(test_set_name)
note = "\tbest for {}".format(test_set_name)
for key, val in test_set_wers:
s += "{}\t{}{}\n".format(key, val, note)
note = ""
logging.info(s)
@torch.no_grad()
def main():
parser = get_parser()
@ -92,15 +334,64 @@ def main():
logging.info("Decoding started")
logging.info(params)
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", 0)
logging.info(f"device: {device}")
HLG = k2.Fsa.from_dict(torch.load(f"{params.lm_dir}/HLG_bpe.pt"))
HLG = HLG.to(device)
assert HLG.requires_grad is False
if not hasattr(HLG, "lm_scores"):
HLG.lm_scores = HLG.scores.clone()
if params.method in ["nbest-rescoring", "whole-lattice-rescoring"]:
if not (params.lm_dir / "G_4_gram.pt").is_file():
logging.info("Loading G_4_gram.fst.txt")
logging.warning("It may take 8 minutes.")
with open(params.lm_dir / "G_4_gram.fst.txt") as f:
first_word_disambig_id = lexicon.words["#0"]
G = k2.Fsa.from_openfst(f.read(), acceptor=False)
# G.aux_labels is not needed in later computations, so
# remove it here.
del G.aux_labels
# CAUTION: The following line is crucial.
# Arcs entering the back-off state have label equal to #0.
# We have to change it to 0 here.
G.labels[G.labels >= first_word_disambig_id] = 0
G = k2.Fsa.from_fsas([G]).to(device)
G = k2.arc_sort(G)
torch.save(G.as_dict(), params.lm_dir / "G_4_gram.pt")
else:
logging.info("Loading pre-compiled G_4_gram.pt")
d = torch.load(params.lm_dir / "G_4_gram.pt")
G = k2.Fsa.from_dict(d).to(device)
if params.method == "whole-lattice-rescoring":
# Add epsilon self-loops to G as we will compose
# it with the whole lattice later
G = k2.add_epsilon_self_loops(G)
G = k2.arc_sort(G)
G = G.to(device)
# G.lm_scores is used to replace HLG.lm_scores during
# LM rescoring.
G.lm_scores = G.scores.clone()
else:
G = None
model = Conformer(
num_features=params.feature_dim,
nhead=params.nhead,
d_model=params.attention_dim,
num_classes=params.num_classes,
num_classes=num_classes,
subsampling_factor=params.subsampling_factor,
num_decoder_layers=params.num_decoder_layers,
vgg_frontend=params.vgg_frontend,
@ -122,7 +413,32 @@ def main():
model.to(device)
model.eval()
token_ids_with_blank = list(range(params.num_classes))
num_param = sum([p.numel() for p in model.parameters()])
logging.info(f"Number of model parameters: {num_param}")
librispeech = LibriSpeechAsrDataModule(args)
# CAUTION: `test_sets` is for displaying only.
# If you want to skip test-clean, you have to skip
# it inside the for loop. That is, use
#
# if test_set == 'test-clean': continue
#
test_sets = ["test-clean", "test-other"]
for test_set, test_dl in zip(test_sets, librispeech.test_dataloaders()):
results_dict = decode_dataset(
dl=test_dl,
params=params,
model=model,
HLG=HLG,
lexicon=lexicon,
G=G,
)
save_results(
params=params, test_set_name=test_set, results_dict=results_dict
)
logging.info("Done!")
if __name__ == "__main__":

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@ -39,7 +39,7 @@ def compile_HLG(lang_dir: str) -> k2.Fsa:
if Path("data/lm/G_3_gram.pt").is_file():
print("Loading pre-compiled G_3_gram")
d = torch.load("data/lm/G_3_gram.pt")
G = k2.Fsa.from_dict(d).to(device)
G = k2.Fsa.from_dict(d)
else:
print("Loading G_3_gram.fst.txt")
with open("data/lm/G_3_gram.fst.txt") as f:
@ -114,7 +114,7 @@ def bpe_based_HLG():
print("Compiling BPE based HLG")
HLG = compile_HLG("data/lang/bpe")
print("Saving HLG.pt to data/lm")
print("Saving HLG_bpe.pt to data/lm")
torch.save(HLG.as_dict(), "data/lm/HLG_bpe.pt")

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@ -326,6 +326,8 @@ def main():
if torch.cuda.is_available():
device = torch.device("cuda", 0)
logging.info(f"device: {device}")
HLG = k2.Fsa.from_dict(torch.load("data/lm/HLG.pt"))
HLG = HLG.to(device)
assert HLG.requires_grad is False

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@ -54,6 +54,7 @@ def get_lattice(
output_beam: float,
min_active_states: int,
max_active_states: int,
subsampling_factor: int = 1,
):
"""Get the decoding lattice from a decoding graph and neural
network output.
@ -87,10 +88,14 @@ def get_lattice(
frame for any given intersection/composition task. This is advisory,
in that it will try not to exceed that but may not always succeed.
You can use a very large number if no constraint is needed.
subsampling_factor:
The subsampling factor of the model.
Returns:
A lattice containing the decoding result.
"""
dense_fsa_vec = k2.DenseFsaVec(nnet_output, supervision_segments)
dense_fsa_vec = k2.DenseFsaVec(
nnet_output, supervision_segments, allow_truncate=subsampling_factor - 1
)
lattice = k2.intersect_dense_pruned(
HLG,