Add decoding script.

This commit is contained in:
Fangjun Kuang 2021-12-13 19:49:50 +08:00
parent 73ba843d0a
commit e38f04e70f
2 changed files with 122 additions and 431 deletions

View File

@ -428,8 +428,6 @@ def decode_dataset(
The first is the reference transcript, and the second is the
predicted result.
"""
results = []
num_cuts = 0
try:

View File

@ -20,31 +20,22 @@ import argparse
import logging
from collections import defaultdict
from pathlib import Path
from typing import Dict, List, Optional, Tuple
from typing import Dict, List, Tuple
import k2
import sentencepiece as spm
import torch
import torch.nn as nn
from asr_datamodule import LibriSpeechAsrDataModule
from conformer import Conformer
from transducer.beam_search import greedy_search
from transducer.conformer import Conformer
from transducer.decoder import Decoder
from transducer.joiner import Joiner
from transducer.model import Transducer
from icefall.bpe_graph_compiler import BpeCtcTrainingGraphCompiler
from icefall.checkpoint import average_checkpoints, load_checkpoint
from icefall.decode import (
get_lattice,
nbest_decoding,
nbest_oracle,
one_best_decoding,
rescore_with_attention_decoder,
rescore_with_n_best_list,
rescore_with_whole_lattice,
)
from icefall.env import get_env_info
from icefall.lexicon import Lexicon
from icefall.utils import (
AttributeDict,
get_texts,
setup_logger,
store_transcripts,
write_error_stats,
@ -72,76 +63,18 @@ def get_parser():
"'--epoch'. ",
)
parser.add_argument(
"--method",
type=str,
default="attention-decoder",
help="""Decoding method.
Supported values are:
- (0) ctc-decoding. Use CTC decoding. It uses a sentence piece
model, i.e., lang_dir/bpe.model, to convert word pieces to words.
It needs neither a lexicon nor an n-gram LM.
- (1) 1best. Extract the best path from the decoding lattice as the
decoding result.
- (2) nbest. Extract n paths from the decoding lattice; the path
with the highest score is the decoding result.
- (3) nbest-rescoring. Extract n paths from the decoding lattice,
rescore them with an n-gram LM (e.g., a 4-gram LM), the path with
the highest score is the decoding result.
- (4) whole-lattice-rescoring. Rescore the decoding lattice with an
n-gram LM (e.g., a 4-gram LM), the best path of rescored lattice
is the decoding result.
- (5) attention-decoder. Extract n paths from the LM rescored
lattice, the path with the highest score is the decoding result.
- (6) nbest-oracle. Its WER is the lower bound of any n-best
rescoring method can achieve. Useful for debugging n-best
rescoring method.
""",
)
parser.add_argument(
"--num-paths",
type=int,
default=100,
help="""Number of paths for n-best based decoding method.
Used only when "method" is one of the following values:
nbest, nbest-rescoring, attention-decoder, and nbest-oracle
""",
)
parser.add_argument(
"--nbest-scale",
type=float,
default=0.5,
help="""The scale to be applied to `lattice.scores`.
It's needed if you use any kinds of n-best based rescoring.
Used only when "method" is one of the following values:
nbest, nbest-rescoring, attention-decoder, and nbest-oracle
A smaller value results in more unique paths.
""",
)
parser.add_argument(
"--exp-dir",
type=str,
default="conformer_ctc/exp",
default="transducer/exp",
help="The experiment dir",
)
parser.add_argument(
"--lang-dir",
"--bpe-model",
type=str,
default="data/lang_bpe_500",
help="The lang dir",
)
parser.add_argument(
"--lm-dir",
type=str,
default="data/lm",
help="""The LM dir.
It should contain either G_4_gram.pt or G_4_gram.fst.txt
""",
default="data/lang_bpe_500/bpe.model",
help="Path to the BPE model",
)
return parser
@ -151,250 +84,138 @@ def get_params() -> AttributeDict:
params = AttributeDict(
{
# parameters for conformer
"feature_dim": 80,
"encoder_out_dim": 512,
"subsampling_factor": 4,
"attention_dim": 512,
"nhead": 8,
"dim_feedforward": 2048,
"num_encoder_layers": 12,
"vgg_frontend": False,
"use_feat_batchnorm": True,
"feature_dim": 80,
"nhead": 8,
"attention_dim": 512,
"num_decoder_layers": 6,
# parameters for decoding
"search_beam": 20,
"output_beam": 8,
"min_active_states": 30,
"max_active_states": 10000,
"use_double_scores": True,
# decoder params
"decoder_embedding_dim": 1024,
"num_decoder_layers": 4,
"decoder_hidden_dim": 512,
"env_info": get_env_info(),
}
)
return params
def get_encoder_model(params: AttributeDict):
# TODO: We can add an option to switch between Conformer and Transformer
encoder = Conformer(
num_features=params.feature_dim,
output_dim=params.encoder_out_dim,
subsampling_factor=params.subsampling_factor,
d_model=params.attention_dim,
nhead=params.nhead,
dim_feedforward=params.dim_feedforward,
num_encoder_layers=params.num_encoder_layers,
vgg_frontend=params.vgg_frontend,
use_feat_batchnorm=params.use_feat_batchnorm,
)
return encoder
def get_decoder_model(params: AttributeDict):
decoder = Decoder(
vocab_size=params.vocab_size,
embedding_dim=params.decoder_embedding_dim,
blank_id=params.blank_id,
sos_id=params.sos_id,
num_layers=params.num_decoder_layers,
hidden_dim=params.decoder_hidden_dim,
output_dim=params.encoder_out_dim,
)
return decoder
def get_joiner_model(params: AttributeDict):
joiner = Joiner(
input_dim=params.encoder_out_dim,
output_dim=params.vocab_size,
)
return joiner
def get_transducer_model(params: AttributeDict):
encoder = get_encoder_model(params)
decoder = get_decoder_model(params)
joiner = get_joiner_model(params)
model = Transducer(
encoder=encoder,
decoder=decoder,
joiner=joiner,
)
return model
def decode_one_batch(
params: AttributeDict,
model: nn.Module,
HLG: Optional[k2.Fsa],
H: Optional[k2.Fsa],
bpe_model: Optional[spm.SentencePieceProcessor],
sp: spm.SentencePieceProcessor,
batch: dict,
word_table: k2.SymbolTable,
sos_id: int,
eos_id: int,
G: Optional[k2.Fsa] = None,
) -> Dict[str, List[List[str]]]:
"""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`
if greedy_search is used, it would be "greedy_search"
If beam search with a beam size of 7 is used, it would be
"beam_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. Used only when params.method is NOT ctc-decoding.
H:
The ctc topo. Used only when params.method is ctc-decoding.
bpe_model:
The BPE model. Used only when params.method is ctc-decoding.
sp:
The BPE model.
batch:
It is the return value from iterating
`lhotse.dataset.K2SpeechRecognitionDataset`. See its documentation
for the format of the `batch`.
word_table:
The word symbol table.
sos_id:
The token ID of the SOS.
eos_id:
The token ID of the EOS.
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. Note: If it decodes to nothing, then return None.
the returned dict.
"""
if HLG is not None:
device = HLG.device
else:
device = H.device
device = model.device
feature = batch["inputs"]
assert feature.ndim == 3
feature = feature.to(device)
# at entry, feature is (N, T, C)
supervisions = batch["supervisions"]
feature_lens = supervisions["num_frames"].to(device)
nnet_output, memory, memory_key_padding_mask = model(feature, supervisions)
# 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)
if H is None:
assert HLG is not None
decoding_graph = HLG
else:
assert HLG is None
assert bpe_model is not None
decoding_graph = H
lattice = get_lattice(
nnet_output=nnet_output,
decoding_graph=decoding_graph,
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,
encoder_out, encoder_out_lens = model.encoder(
x=feature, x_lens=feature_lens
)
hyps = []
batch_size = encoder_out.size(0)
if params.method == "ctc-decoding":
best_path = one_best_decoding(
lattice=lattice, use_double_scores=params.use_double_scores
)
# Note: `best_path.aux_labels` contains token IDs, not word IDs
# since we are using H, not HLG here.
#
# token_ids is a lit-of-list of IDs
token_ids = get_texts(best_path)
for i in range(batch_size):
# fmt: off
encoder_out_i = encoder_out[i:i+1, :encoder_out_lens[i]]
# fmt: on
hyp = greedy_search(model=model, encoder_out=encoder_out_i)
hyps.append(sp.decode(hyp).split())
# hyps is a list of str, e.g., ['xxx yyy zzz', ...]
hyps = bpe_model.decode(token_ids)
# hyps is a list of list of str, e.g., [['xxx', 'yyy', 'zzz'], ... ]
hyps = [s.split() for s in hyps]
key = "ctc-decoding"
return {key: hyps}
if params.method == "nbest-oracle":
# Note: You can also pass rescored lattices to it.
# We choose the HLG decoded lattice for speed reasons
# as HLG decoding is faster and the oracle WER
# is only slightly worse than that of rescored lattices.
best_path = nbest_oracle(
lattice=lattice,
num_paths=params.num_paths,
ref_texts=supervisions["text"],
word_table=word_table,
nbest_scale=params.nbest_scale,
oov="<UNK>",
)
hyps = get_texts(best_path)
hyps = [[word_table[i] for i in ids] for ids in hyps]
key = f"oracle_{params.num_paths}_nbest_scale_{params.nbest_scale}" # noqa
return {key: hyps}
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,
nbest_scale=params.nbest_scale,
)
key = f"no_rescore-nbest-scale-{params.nbest_scale}-{params.num_paths}" # noqa
hyps = get_texts(best_path)
hyps = [[word_table[i] for i in ids] for ids in hyps]
return {key: hyps}
assert params.method in [
"nbest-rescoring",
"whole-lattice-rescoring",
"attention-decoder",
]
lm_scale_list = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7]
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,
nbest_scale=params.nbest_scale,
)
elif params.method == "whole-lattice-rescoring":
best_path_dict = rescore_with_whole_lattice(
lattice=lattice,
G_with_epsilon_loops=G,
lm_scale_list=lm_scale_list,
)
elif params.method == "attention-decoder":
# lattice uses a 3-gram Lm. We rescore it with a 4-gram LM.
rescored_lattice = rescore_with_whole_lattice(
lattice=lattice,
G_with_epsilon_loops=G,
lm_scale_list=None,
)
# TODO: pass `lattice` instead of `rescored_lattice` to
# `rescore_with_attention_decoder`
best_path_dict = rescore_with_attention_decoder(
lattice=rescored_lattice,
num_paths=params.num_paths,
model=model,
memory=memory,
memory_key_padding_mask=memory_key_padding_mask,
sos_id=sos_id,
eos_id=eos_id,
nbest_scale=params.nbest_scale,
)
else:
assert False, f"Unsupported decoding method: {params.method}"
ans = dict()
if best_path_dict is not None:
for lm_scale_str, best_path in best_path_dict.items():
hyps = get_texts(best_path)
hyps = [[word_table[i] for i in ids] for ids in hyps]
ans[lm_scale_str] = hyps
else:
ans = None
return ans
return {"greedy_search": hyps}
# TODO: Implement beam search
def decode_dataset(
dl: torch.utils.data.DataLoader,
params: AttributeDict,
model: nn.Module,
HLG: Optional[k2.Fsa],
H: Optional[k2.Fsa],
bpe_model: Optional[spm.SentencePieceProcessor],
word_table: k2.SymbolTable,
sos_id: int,
eos_id: int,
G: Optional[k2.Fsa] = None,
sp: spm.SentencePieceProcessor,
) -> Dict[str, List[Tuple[List[str], List[str]]]]:
"""Decode dataset.
@ -405,31 +226,15 @@ def decode_dataset(
It is returned by :func:`get_params`.
model:
The neural model.
HLG:
The decoding graph. Used only when params.method is NOT ctc-decoding.
H:
The ctc topo. Used only when params.method is ctc-decoding.
bpe_model:
The BPE model. Used only when params.method is ctc-decoding.
word_table:
It is the word symbol table.
sos_id:
The token ID for SOS.
eos_id:
The token ID for EOS.
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.
sp:
The BPE model.
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.
Return a dict, whose key may be "greedy_search" if greedy search
is used, or it may be "beam_7" if beam size of 7 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
try:
@ -444,37 +249,18 @@ def decode_dataset(
hyps_dict = decode_one_batch(
params=params,
model=model,
HLG=HLG,
H=H,
bpe_model=bpe_model,
sp=sp,
batch=batch,
word_table=word_table,
G=G,
sos_id=sos_id,
eos_id=eos_id,
)
if hyps_dict is not None:
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)
else:
assert (
len(results) > 0
), "It should not decode to empty in the first batch!"
for name, hyps in hyps_dict.items():
this_batch = []
hyp_words = []
for ref_text in texts:
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))
for lm_scale in results.keys():
results[lm_scale].extend(this_batch)
results[name].extend(this_batch)
num_cuts += len(texts)
@ -492,31 +278,22 @@ def save_results(
test_set_name: str,
results_dict: Dict[str, List[Tuple[List[int], List[int]]]],
):
if params.method == "attention-decoder":
# Set it to False since there are too many logs.
enable_log = False
else:
enable_log = True
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)
if enable_log:
logging.info(f"The transcripts are stored in {recog_path}")
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, enable_log=enable_log
f, f"{test_set_name}-{key}", results, enable_log=True
)
test_set_wers[key] = wer
if enable_log:
logging.info(
"Wrote detailed error stats to {}".format(errs_filename)
)
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"
@ -539,113 +316,31 @@ def main():
LibriSpeechAsrDataModule.add_arguments(parser)
args = parser.parse_args()
args.exp_dir = Path(args.exp_dir)
args.lang_dir = Path(args.lang_dir)
args.lm_dir = Path(args.lm_dir)
params = get_params()
params.update(vars(args))
setup_logger(f"{params.exp_dir}/log-{params.method}/log-decode")
setup_logger(f"{params.exp_dir}/log-decode")
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}")
logging.info(f"Device: {device}")
graph_compiler = BpeCtcTrainingGraphCompiler(
params.lang_dir,
device=device,
sos_token="<sos/eos>",
eos_token="<sos/eos>",
)
sos_id = graph_compiler.sos_id
eos_id = graph_compiler.eos_id
sp = spm.SentencePieceProcessor()
sp.load(params.bpe_model)
if params.method == "ctc-decoding":
HLG = None
H = k2.ctc_topo(
max_token=max_token_id,
modified=False,
device=device,
)
bpe_model = spm.SentencePieceProcessor()
bpe_model.load(str(params.lang_dir / "bpe.model"))
else:
H = None
bpe_model = None
HLG = k2.Fsa.from_dict(
torch.load(f"{params.lang_dir}/HLG.pt", map_location=device)
)
assert HLG.requires_grad is False
# <blk> and <sos/eos> are defined in local/train_bpe_model.py
params.blank_id = sp.piece_to_id("<blk>")
params.sos_id = sp.piece_to_id("<sos/eos>")
params.vocab_size = sp.get_piece_size()
if not hasattr(HLG, "lm_scores"):
HLG.lm_scores = HLG.scores.clone()
logging.info(params)
if params.method in (
"nbest-rescoring",
"whole-lattice-rescoring",
"attention-decoder",
):
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.word_table["#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
# See https://github.com/k2-fsa/k2/issues/874
# for why we need to set G.properties to None
G.__dict__["_properties"] = None
G = k2.Fsa.from_fsas([G]).to(device)
G = k2.arc_sort(G)
# Save a dummy value so that it can be loaded in C++.
# See https://github.com/pytorch/pytorch/issues/67902
# for why we need to do this.
G.dummy = 1
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", map_location=device)
G = k2.Fsa.from_dict(d)
if params.method in ["whole-lattice-rescoring", "attention-decoder"]:
# 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=num_classes,
subsampling_factor=params.subsampling_factor,
num_decoder_layers=params.num_decoder_layers,
vgg_frontend=params.vgg_frontend,
use_feat_batchnorm=params.use_feat_batchnorm,
)
logging.info("About to create model")
model = get_transducer_model(params)
if params.avg == 1:
load_checkpoint(f"{params.exp_dir}/epoch-{params.epoch}.pt", model)
@ -661,6 +356,8 @@ def main():
model.to(device)
model.eval()
model.device = device
num_param = sum([p.numel() for p in model.parameters()])
logging.info(f"Number of model parameters: {num_param}")
@ -680,17 +377,13 @@ def main():
dl=test_dl,
params=params,
model=model,
HLG=HLG,
H=H,
bpe_model=bpe_model,
word_table=lexicon.word_table,
G=G,
sos_id=sos_id,
eos_id=eos_id,
sp=sp,
)
save_results(
params=params, test_set_name=test_set, results_dict=results_dict
params=params,
test_set_name=test_set,
results_dict=results_dict,
)
logging.info("Done!")