# eos_score, log_add, criterion_type (ASG or CTC))
opts = DecoderOptions(2500, 25000, 100.0, 2.0, 2.0, -math.inf, -1, 0,
False, CriterionType.ASG)
# define lexicon beam-search decoder with word-level lm
# LexiconDecoder(decoder options, trie, lm, silence index,
# blank index (for CTC), unk index,
# transitiona matrix, is token-level lm)
decoder = LexiconDecoder(opts, trie, lm, sil_idx, -1, unk_idx, transitions,
False)
# run decoding
# decoder.decode(emissions, Time, Ntokens)
# result is a list of sorted hypothesis, 0-index is the best hypothesis
# each hypothesis is a struct with "score" and "words" representation
# in the hypothesis and the "tokens" representation
results = decoder.decode(emissions.ctypes.data, T, N)
print(f"Decoding complete, obtained {len(results)} results")
print("Showing top 5 results:")
for i in range(min(5, len(results))):
prediction = []
for idx in results[i].tokens:
if idx < 0:
break
prediction.append(token_dict.get_entry(idx))
prediction = " ".join(prediction)
print(f"score={results[i].score} prediction='{prediction}'")
assert len(results) == 16
hyp_score_target = [-284.0998, -284.108, -284.119, -284.127, -284.296]
for i in range(min(5, len(results))):
class W2lKenLMDecoder(W2lDecoder):
def __init__(self, args, tgt_dict):
super().__init__(args, tgt_dict)
self.silence = (tgt_dict.index("<ctc_blank>") if "<ctc_blank>"
in tgt_dict.indices else tgt_dict.bos())
self.lexicon = load_words(args.lexicon)
self.word_dict = create_word_dict(self.lexicon)
self.unk_word = self.word_dict.get_index("<unk>")
self.lm = KenLM(args.kenlm_model, self.word_dict)
self.trie = Trie(self.vocab_size, self.silence)
start_state = self.lm.start(False)
for i, (word, spellings) in enumerate(self.lexicon.items()):
word_idx = self.word_dict.get_index(word)
_, score = self.lm.score(start_state, word_idx)
for spelling in spellings:
spelling_idxs = [tgt_dict.index(token) for token in spelling]
assert (tgt_dict.unk()
not in spelling_idxs), f"{spelling} {spelling_idxs}"
self.trie.insert(spelling_idxs, word_idx, score)
self.trie.smear(SmearingMode.MAX)
self.decoder_opts = DecoderOptions(
args.beam,
int(getattr(args, "beam_size_token", len(tgt_dict))),
args.beam_threshold,
args.lm_weight,
args.word_score,
args.unk_weight,
args.sil_weight,
0,
False,
self.criterion_type,
)
if self.asg_transitions is None:
N = 768
# self.asg_transitions = torch.FloatTensor(N, N).zero_()
self.asg_transitions = []
self.decoder = LexiconDecoder(
self.decoder_opts,
self.trie,
self.lm,
self.silence,
self.blank,
self.unk_word,
self.asg_transitions,
False,
)
def decode(self, emissions):
B, T, N = emissions.size()
hypos = []
for b in range(B):
emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
results = self.decoder.decode(emissions_ptr, T, N)
nbest_results = results[:self.nbest]
hypos.append([{
"tokens":
self.get_tokens(result.tokens),
"score":
result.score,
"words":
[self.word_dict.get_entry(x) for x in result.words if x >= 0],
} for result in nbest_results])
return hypos
class W2lFairseqLMDecoder(W2lDecoder):
def __init__(self, args, tgt_dict):
super().__init__(args, tgt_dict)
# self.silence = tgt_dict.bos()
self.silence = 1
self.unit_lm = getattr(args, "unit_lm", False)
self.lexicon = load_words(args.lexicon) if args.lexicon else None
self.idx_to_wrd = {}
checkpoint = torch.load(args.kenlm_model, map_location="cpu")
lm_args = checkpoint["args"]
lm_args.data = osp.dirname(args.kenlm_model)
print(lm_args)
# import pdb; pdb.set_trace()
# lm_args.data = ''
task = tasks.setup_task(lm_args)
model = task.build_model(lm_args)
model.load_state_dict(checkpoint["model"], strict=False)
self.trie = Trie(self.vocab_size, self.silence)
self.word_dict = task.dictionary
self.unk_word = self.word_dict.unk()
self.lm = FairseqLM(self.word_dict, model)
self.decoder_opts = DecoderOptions(
args.beam,
int(getattr(args, "beam_size_token", len(tgt_dict))),
args.beam_threshold,
args.lm_weight,
args.word_score,
args.unk_weight,
args.sil_weight,
0,
False,
self.criterion_type,
)
if self.lexicon:
start_state = self.lm.start(False)
for i, (word, spellings) in enumerate(self.lexicon.items()):
if self.unit_lm:
word_idx = i
self.idx_to_wrd[i] = word
score = 0
else:
word_idx = self.word_dict.index(word)
_, score = self.lm.score(start_state,
word_idx,
no_cache=True)
# spellings (rightside in lexicon) should nor be unk
for spelling in spellings:
spelling_idxs = [
tgt_dict.index(token) for token in spelling
]
# if tgt_dict.unk() in spelling_idxs:
# print(spelling)
assert (
tgt_dict.unk() not in spelling_idxs
), f"{spelling} is unk: {spelling_idxs} for acoustic output"
self.trie.insert(spelling_idxs, word_idx, score)
self.trie.smear(SmearingMode.MAX)
self.decoder = LexiconDecoder(
self.decoder_opts,
self.trie,
self.lm,
self.silence,
self.blank,
self.unk_word,
[],
self.unit_lm,
)
# else:
# self.decoder = LexiconFreeDecoder(
# self.decoder_opts, self.lm, self.silence, self.blank, []
# )
def decode(self, emissions):
B, T, N = emissions.size()
hypos = []
def idx_to_word(idx):
if self.unit_lm:
return self.idx_to_wrd[idx]
else:
return self.word_dict[idx]
def make_hypo(result):
hypo = {
"tokens": self.get_tokens(result.tokens),
"score": result.score
}
if self.lexicon:
hypo["words"] = [
idx_to_word(x) for x in result.words if x >= 0
]
return hypo
for b in range(B):
emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
results = self.decoder.decode(emissions_ptr, T, N)
nbest_results = results[:self.nbest]
hypos.append([make_hypo(result) for result in nbest_results])
self.lm.empty_cache()
return hypos