def greedy_decode(self, encoder_output, feature_mask):
"""
batched greedy decode
"""
batch_size = encoder_output.size(0)
device = encoder_output.device
token_id = t.full((batch_size, 1), fill_value=self.bos_id, dtype=t.long, device=device)
length = t.LongTensor([1] * batch_size).to(device)
#probs = t.Tensor().to(device)
with t.no_grad():
for i in range(self.max_length):
try:
token_mask = Masker.get_mask(length)
self_attention_mask = Masker.get_dot_mask(token_mask, token_mask)
self_attention_mask = Masker.get_forward_mask(self_attention_mask)
dot_attention_mask = Masker.get_dot_mask(token_mask, feature_mask)
last_prob, last_token_id = self.decode_step(
token_id, encoder_output, token_mask, self_attention_mask, dot_attention_mask,
topk=1, return_last=True)
token_id = t.cat([token_id, last_token_id], dim=1)
# print('concate, tokenid', token_id)
#probs = t.cat([probs, last_prob], dim=1)
for index, id in enumerate(last_token_id.squeeze(1)):
if id != self.eos_id:
length[index] += 1
except:
#TODO: to be more consious
break
return token_id
def _prepare_token(self, token, token_length):
input_token, output_token, token_length = self._rebuild_target(
token, token_length)
token_mask = Masker.get_mask(token_length)
token_self_attention_mask = Masker.get_dot_mask(token_mask, token_mask)
token_self_attention_mask = Masker.get_forward_mask(
token_self_attention_mask)
return input_token, output_token, token_length, token_mask, token_self_attention_mask
def beam_search_decode(self, encoder_output, feature_mask, beam_size, best_k=5, lp_eps=0.0):
batch_size, feature_length, _ = encoder_output.size()
device = encoder_output.device
self.beam_steper = BeamSteper(
batch_size=batch_size, beam_size=beam_size, bos_id=self.bos_id, eos_id=self.eos_id,
vocab_size=self.vocab_size, device=device, k_best=best_k, lp_eps=lp_eps
)
beam_feature_mask = feature_mask.unsqueeze(1).repeat(1, beam_size, 1).view(batch_size*beam_size, -1)
beam_encoder_output = encoder_output.unsqueeze(1).repeat(1, beam_size, 1, 1).view(batch_size*beam_size, feature_length, -1)
with t.no_grad():
for i in range(self.max_length):
if i == 0:
token_id = self.beam_steper.get_first_step_token()
length = self.beam_steper.get_first_step_length()
token_mask = Masker.get_mask(length)
self_attention_mask = Masker.get_dot_mask(token_mask, token_mask)
self_attention_mask = Masker.get_forward_mask(self_attention_mask)
dot_attention_mask = Masker.get_dot_mask(token_mask, feature_mask)
last_prob = self.beam_decode_step(
token_id, encoder_output, token_mask, self_attention_mask, dot_attention_mask)
if_continue = self.beam_steper.first_step(last_prob)
if not if_continue:
break
else:
token_id = self.beam_steper.token_container
token_id = token_id.view(batch_size * beam_size, -1)
length = self.beam_steper.length_container
length = length.view(batch_size * beam_size)
token_mask = Masker.get_mask(length)
self_attention_mask = Masker.get_dot_mask(token_mask, token_mask)
self_attention_mask = Masker.get_forward_mask(self_attention_mask)
dot_attention_mask = Masker.get_dot_mask(token_mask, beam_feature_mask)
last_prob = self.beam_decode_step(
token_id, beam_encoder_output, token_mask, self_attention_mask, dot_attention_mask
)
if_continue = self.beam_steper.step(last_prob.view(batch_size, beam_size, -1))
if not if_continue:
break
output_token = self.beam_steper.batch_best_saver.batch
return output_token
def _prepare_token(self, token, token_length):
"""
build target and mask
"""
input_token, output_token, token_length = self._rebuild_target(
token, token_length)
token_mask = Masker.get_mask(token_length)
token_self_attention_mask = Masker.get_dot_mask(token_mask, token_mask)
token_self_attention_mask = Masker.get_forward_mask(
token_self_attention_mask)
switch = t.ones_like(output_token,
device=token.device).long() # eng = 1
switch.masked_fill_(output_token.eq(0), 0) # pad=0
switch.masked_fill_((output_token.ge(12) & output_token.le(4211)),
2) # ch = 2
switch.masked_fill_((output_token.ge(1) & output_token.le(10)),
3) # other = 3
return input_token, output_token, token_length, token_mask, token_self_attention_mask, switch
def recognize(self,
feature,
feature_length,
beam=5,
penalty=0,
ctc_weight=0.3,
maxlenratio=0,
minlenratio=0,
char_list=None,
rnnlm=None,
lm_weight=0.1,
nbest=1):
"""Recognize input speech.
:param ndnarray x: input acoustic feature (B, T, D) ,length (B)
:param Namespace recog_args: argment Namespace contraining options
:param list char_list: list of characters
:param torch.nn.Module rnnlm: language model module
:return: N-best decoding results
:rtype: list
"""
assert feature.size(0) == 1
enc_output, feature_mask = self._encode(feature, feature_length)
if ctc_weight > 0.0:
lpz = t.nn.functional.log_softmax(self.encoder_linear(enc_output),
-1).squeeze(0)
else:
lpz = None
h = enc_output.squeeze(0)
# print('input lengths: ' + str(h.size(0)))
# preprare sos
y = self.vocab.bos_id
vy = h.new_zeros(1).long()
if maxlenratio == 0:
maxlen = h.shape[0]
else:
# maxlen >= 1
maxlen = max(1, int(maxlenratio * h.size(0)))
minlen = int(minlenratio * h.size(0))
# print('max output length: ' + str(maxlen))
# print('min output length: ' + str(minlen))
# initialize hypothesis
if rnnlm:
hyp = {'score': 0.0, 'yseq': [y], 'rnnlm_prev': None}
else:
hyp = {'score': 0.0, 'yseq': [y]}
if lpz is not None:
ctc_prefix_score = CTCPrefixScore(lpz.detach().numpy(),
self.vocab.blank_id,
self.vocab.eos_id, np)
hyp['ctc_state_prev'] = ctc_prefix_score.initial_state()
hyp['ctc_score_prev'] = 0.0
if ctc_weight != 1.0:
# pre-pruning based on attention scores
ctc_beam = min(lpz.shape[-1], int(beam * CTC_SCORING_RATIO))
else:
ctc_beam = lpz.shape[-1]
hyps = [hyp]
ended_hyps = []
import six
for i in six.moves.range(maxlen):
# print('position ' + str(i))
hyps_best_kept = []
for hyp in hyps:
vy[0] = hyp['yseq'][i]
# get nbest local scores and their ids
ys_mask = Masker.get_mask(t.LongTensor([i + 1]))
ys_self_attention_mask = Masker.get_dot_mask(ys_mask, ys_mask)
ys_self_attention_mask = Masker.get_forward_mask(
ys_self_attention_mask)
dot_attention_mask = Masker.get_dot_mask(ys_mask, feature_mask)
ys = t.tensor(hyp['yseq']).unsqueeze(0)
local_att_scores = self.token_decoder.forward_one_step(
ys, enc_output, ys_mask, ys_self_attention_mask,
dot_attention_mask)[0]
local_att_scores = t.nn.functional.log_softmax(
local_att_scores, -1)
if rnnlm:
rnnlm_state, local_lm_scores = rnnlm.predict(
hyp['rnnlm_prev'], vy)
local_scores = local_att_scores + lm_weight * local_lm_scores
else:
local_scores = local_att_scores
if lpz is not None:
local_best_scores, local_best_ids = t.topk(
local_att_scores, ctc_beam, dim=1)
ctc_scores, ctc_states = ctc_prefix_score(
hyp['yseq'], local_best_ids[0], hyp['ctc_state_prev'])
local_scores = \
(1.0 - ctc_weight) * local_att_scores[:, local_best_ids[0]] \
+ ctc_weight * t.from_numpy(ctc_scores - hyp['ctc_score_prev'])
if rnnlm:
local_scores += lm_weight * local_lm_scores[:,
local_best_ids[
0]]
local_best_scores, joint_best_ids = t.topk(local_scores,
beam,
dim=1)
local_best_ids = local_best_ids[:, joint_best_ids[0]]
else:
local_best_scores, local_best_ids = t.topk(local_scores,
beam,
dim=1)
for j in six.moves.range(beam):
new_hyp = {}
new_hyp['score'] = hyp['score'] + float(
local_best_scores[0, j])
new_hyp['yseq'] = [0] * (1 + len(hyp['yseq']))
new_hyp['yseq'][:len(hyp['yseq'])] = hyp['yseq']
new_hyp['yseq'][len(hyp['yseq'])] = int(local_best_ids[0,
j])
if rnnlm:
new_hyp['rnnlm_prev'] = rnnlm_state
if lpz is not None:
new_hyp['ctc_state_prev'] = ctc_states[joint_best_ids[
0, j]]
new_hyp['ctc_score_prev'] = ctc_scores[joint_best_ids[
0, j]]
# will be (2 x beam) hyps at most
hyps_best_kept.append(new_hyp)
hyps_best_kept = sorted(hyps_best_kept,
key=lambda x: x['score'],
reverse=True)[:beam]
# sort and get nbest
hyps = hyps_best_kept
# print('number of pruned hypothes: ' + str(len(hyps)))
# if char_list is not None:
# print(
# 'best hypo: ' + ''.join([char_list[int(x)] for x in hyps[0]['yseq'][1:]]))
# add eos in the final loop to avoid that there are no ended hyps
if i == maxlen - 1:
# print('adding <eos> in the last postion in the loop')
for hyp in hyps:
hyp['yseq'].append(self.vocab.eos_id)
# add ended hypothes to a final list, and removed them from current hypothes
# (this will be a probmlem, number of hyps < beam)
remained_hyps = []
for hyp in hyps:
if hyp['yseq'][-1] == self.vocab.eos_id:
# only store the sequence that has more than minlen outputs
# also add penalty
if len(hyp['yseq']) > minlen:
hyp['score'] += (i + 1) * penalty
if rnnlm: # Word LM needs to add final <eos> score
hyp['score'] += lm_weight * rnnlm.final(
hyp['rnnlm_prev'])
ended_hyps.append(hyp)
else:
remained_hyps.append(hyp)
# end detection
# if end_detect(ended_hyps, i) and maxlenratio == 0.0:
# print('end detected at %d', i)
# # break
hyps = remained_hyps
# if len(hyps) > 0:
# # pass
# print('remeined hypothes: ' + str(len(hyps)))
# else:
# print('no hypothesis. Finish decoding.')
# # break
# if char_list is not None:
# for hyp in hyps:
# print(
# 'hypo: ' + ''.join([char_list[int(x)] for x in hyp['yseq'][1:]]))
#
# print('number of ended hypothes: ' + str(len(ended_hyps)))
nbest_hyps = sorted(ended_hyps, key=lambda x: x['score'],
reverse=True)[:min(len(ended_hyps), nbest)]
# check number of hypotheis
if len(nbest_hyps) == 0:
# print('there is no N-best results, perform recognition again with smaller minlenratio.')
# should copy becasuse Namespace will be overwritten globally
return None
# recog_args = Namespace(**vars(recog_args))
# recog_args.minlenratio = max(0.0, recog_args.minlenratio - 0.1)
# return self.recognize(x, recog_args, char_list, rnnlm)
# print('total log probability: ' + str(nbest_hyps[0]['score']))
# print('normalized log probability: ' + str(nbest_hyps[0]['score'] / len(nbest_hyps[0]['yseq'])))
return nbest_hyps