def forward(self, inputs, subword_select_mask, subword_lens, lens):
selected_inputs = inputs.masked_select(subword_select_mask.unsqueeze(-1))
reshaped_inputs = selected_inputs.new_zeros(subword_lens.size(0), max(subword_lens.tolist()), self.hidden_size)
subword_mask = lens2mask(subword_lens)
reshaped_inputs = reshaped_inputs.masked_scatter_(subword_mask.unsqueeze(-1), selected_inputs)
# aggregate subword into word feats
reshaped_inputs = self.aggregation(reshaped_inputs, mask=subword_mask)
outputs = inputs.new_zeros(lens.size(0), max(lens.tolist()), self.hidden_size)
outputs.masked_scatter_(lens2mask(lens).unsqueeze(-1), reshaped_inputs)
return outputs
def forward(self, *inputs):
'''
@args:
hidden_states: RNN hidden states
encoder_output: bsize x seqlen x hsize*2
lens: length for each instance
'''
if self.method == 'head+tail':
ht = inputs[0][0] if self.h_c else inputs[0]
last = ht.size(0)
index = [last - 2, last - 1]
index = torch.tensor(index, dtype=torch.long, device=ht.device)
ht = torch.index_select(ht, 0, index)
sent = ht.transpose(0,1).contiguous().view(-1, 2 * self.hidden_size)
elif self.method == 'hiddenAttn':
hc, lstm_out, lens = inputs[0], inputs[1], inputs[2]
ht = hc[0][-1] if self.h_c else hc[-1]
hiddens = lstm_out.transpose(1, 2)
c1 = self.Wa(self.dropout_layer(ht))
c2 = self.Ua(self.dropout_layer(hiddens))
c3 = c1.unsqueeze(2).repeat(1, 1, lstm_out.size(1))
c4 = torch.tanh(c3 + c2)
e = self.Va(c4).squeeze(1)
e.masked_fill_(lens2mask(lens) == 0, -float('inf'))
a = F.softmax(e, dim=1)
sent = torch.bmm(hiddens, a.unsqueeze(2)).squeeze(2)
else:
raise ValueError('Unrecognized intent detection method!')
return F.log_softmax(self.decoder(self.dropout_layer(sent)), dim=1)
def forward(self, inputs, lens, dec_inputs=None):
outputs, hidden_states = self.encoder(self.word_embed(inputs), lens)
bios = self.slot_decoder(outputs)
bios = self.crf_layer.neg_log_likelihood_loss(bios, lens2mask(lens),
dec_inputs[:, 1:])
intents = self.intent_decoder(hidden_states, outputs, lens)
return bios, intents
def decode_batch(self,
src_inputs,
src_lens,
vocab,
copy_tokens=None,
beam_size=5,
n_best=1,
alpha=0.6,
length_pen='avg'):
enc_out, hidden_states = self.encoder(self.src_embed(src_inputs),
src_lens)
hidden_states = self.enc2dec(hidden_states)
src_mask = lens2mask(src_lens)
if beam_size == 1:
return self.decode_greed(hidden_states, enc_out, src_mask, vocab,
copy_tokens)
else:
return self.decode_beam_search(hidden_states,
enc_out,
src_mask,
vocab,
copy_tokens,
beam_size=beam_size,
n_best=n_best,
alpha=alpha,
length_pen=length_pen)
def forward(self, slot_seq, slot_lens, intent_emb):
"""
@args:
slot_seq: bsize x max_slot_num x slot_dim
slot_lens: tensor of # slot=value pair, bsize
intent_emb: bsize x intent_dim
@return:
num_layers x bsize x hidden_size
"""
if torch.sum(slot_lens).item() == 0:
h = slot_lens.new_zeros(self.num_layers, slot_lens.size(0), self.hidden_size).float().contiguous()
if self.cell == 'LSTM':
c = h.new_zeros(h.size()).contiguous()
return (h, c)
return h
slot_seq = self.dropout_layer(slot_seq)
weights = torch.bmm(self.attn(slot_seq), intent_emb.unsqueeze(dim=-1)).squeeze(dim=-1)
weights.masked_fill_(lens2mask(slot_lens) == 0, -1e8)
a = F.softmax(weights, dim=-1)
conxt = torch.bmm(a.unsqueeze(dim=1), slot_seq).squeeze(dim=1)
h = torch.tanh(self.affine(conxt)).unsqueeze(dim=0).repeat(self.num_layers, 1, 1).contiguous()
if self.cell == 'LSTM':
c = h.new_zeros(h.size()).contiguous()
return (h, c)
return h
def forward(self, hiddens, decoder_state, slot_lens):
'''
@args:
hiddens : bsize x max_slot_num x enc_dim
decoder_state : bsize x dec_dim
slot_lens : slot number for each batch, bsize
@return:
context : bsize x 1 x enc_dim
a : normalized coefficient, bsize x max_slot_num
'''
decoder_state = self.dropout_layer(decoder_state)
if self.method == 'dot':
m = self.Wa(self.dropout_layer(hiddens))
m = m.transpose(-1, -2)
e = torch.bmm(decoder_state.unsqueeze(1), m).squeeze(dim=1)
else:
d = decoder_state.unsqueeze(dim=1).repeat(1, hiddens.size(1), 1)
e = self.Wa(torch.cat([d, self.dropout_layer(hiddens)], dim=-1))
e = self.Va(torch.tanh(e)).squeeze(dim=-1)
masks = lens2mask(slot_lens)
if masks.size(1) < e.size(1):
masks = torch.cat([
masks,
torch.zeros(masks.size(0),
e.size(1) - masks.size(1)).type_as(masks).to(
masks.device)
],
dim=1)
e.masked_fill_(masks == 0, -1e8)
a = F.softmax(e, dim=1)
context = torch.bmm(a.unsqueeze(1), hiddens)
return context, a
def forward(self, src_inputs, src_lens, tgt_inputs, copy_tokens=None):
"""
Used during training time.
"""
enc_out, hidden_states = self.encoder(self.src_embed(src_inputs),
src_lens)
hidden_states = self.enc2dec(hidden_states)
src_mask = lens2mask(src_lens)
dec_out, _ = self.decoder(self.tgt_embed(tgt_inputs), hidden_states,
enc_out, src_mask, copy_tokens)
out = self.generator(dec_out)
return out
def reconstruction_reward(self, logscores, references, lens):
"""
logscores: bsize x max_out_len x vocab_size[ + MAX_OOV_NUM]
references: bsize x max_out_len
lens: len for each sample
"""
mask = lens2mask(lens)
pick_score = torch.gather(
logscores, dim=-1,
index=references.unsqueeze(dim=-1)).squeeze(dim=-1)
masked_score = mask.float() * pick_score
reward = masked_score.sum(dim=1)
return reward
def sent_logprobability(self, input_feats, lens):
'''
Given sentences, calculate its length-normalized log-probability
Sequence must contain <s> and </s> symbol
lens: length tensor
'''
lens = lens - 1
input_feats, output_feats = input_feats[:, :-1], input_feats[:, 1:]
emb = self.dropout_layer(
self.encoder(input_feats)) # bsize, seq_len, emb_size
output, _ = rnn_wrapper(self.rnn, emb, lens, self.cell)
decoded = self.decoder(self.affine(self.dropout_layer(output)))
scores = F.log_softmax(decoded, dim=-1)
log_prob = torch.gather(scores, 2,
output_feats.unsqueeze(-1)).contiguous().view(
output.size(0), output.size(1))
sent_log_prob = torch.sum(log_prob * lens2mask(lens).float(), dim=-1)
return sent_log_prob / lens.float()
def sent_logprob(self, inputs, lens, length_norm=False):
''' Given sentences, calculate the log-probability for each sentence
@args:
inputs(torch.LongTensor): sequence must contain <s> and </s> symbol
lens(torch.LongTensor): length tensor
@return:
sent_logprob(torch.FloatTensor): logprob for each sent in the batch
'''
lens = lens - 1
inputs, outputs = inputs[:, :-1], inputs[:, 1:]
emb = self.dropout_layer(self.word_embed(inputs)) # bsize, seq_len, emb_size
output, _ = rnn_wrapper(self.encoder, emb, lens, self.cell)
decoded = self.decoder(self.dropout_layer(output))
scores = F.log_softmax(decoded, dim=-1)
logprob = torch.gather(scores, 2, outputs.unsqueeze(-1)).contiguous().view(output.size(0), output.size(1))
sent_logprob = torch.sum(logprob * lens2mask(lens).float(), dim=-1)
if length_norm:
return sent_logprob / lens.float()
else:
return sent_logprob
def forward(self, slot_emb, slot_lens, lens):
"""
@args:
slot_emb: [total_slot_num, max_slot_word_len, emb_size]
slot_lens: slot_num for each training sample, [bsize]
lens: seq_len for each ${slot}=value sequence, [total_slot_num]
@return:
slot_feats: bsize, max_slot_num, hidden_size * 2
"""
if slot_emb is None or torch.sum(slot_lens).item() == 0:
# set seq_len dim to 1 due to decoder attention computation
return torch.zeros(slot_lens.size(0), 1, self.hidden_size * 2, dtype=torch.float).to(slot_lens.device)
slot_outputs, _ = rnn_wrapper(self.slot_encoder, slot_emb, lens, self.cell)
slot_outputs = self.slot_aggregation(slot_outputs, lens2mask(lens))
chunks = slot_outputs.split(slot_lens.tolist(), dim=0) # list of [slot_num x hidden_size]
max_slot_num = torch.max(slot_lens).item()
padded_chunks = [torch.cat([each, each.new_zeros(max_slot_num - each.size(0), each.size(1))], dim=0) for each in chunks]
# bsize x max_slot_num x hidden_size
slot_feats = torch.stack(padded_chunks, dim=0)
return slot_feats
def decode_greed(self, bios, intents, lens):
"""
@args:
bios(torch.FloatTensor): bsize x seqlen x slot_num
intents(torch.FloatTensor): bsize x intent_num
lens(torch.LongTensor): bsize
@return:
dict:
slot: tuple of
slot_score(torch.FloatTensor): bsize x 1
slot_idx(list): such as [ [[1, 2, 4, 9, 11]] , [[1, 2, 5, 8, 10]] , ... ]
intent: tuple of
intent_score(torch.FloatTensor): bsize x 1
intent_idx(list): bsize x 1
"""
slot_score, slot_idx = self.crf_layer._viterbi_decode(
bios, lens2mask(lens))
int_score, int_idx = torch.max(intents, dim=1, keepdim=True)
return {
"intent": (int_score, int_idx.tolist()),
"slot": (slot_score, slot_idx.tolist())
}
def decode_beam_search(self, bios, intents, lens, n_best=1, **kargs):
"""
@args:
n_best(int): number of predictions to return
@return:
dict:
(key)intent: (value) tuple of (n_best most likely intent score, n_best most likely intent idx)
intent_score(torch.FloatTensor): bsize x n_best
intent_idx(list): bsize x n_best
(key)slot: (value) tuple of (n_best most likely seq score, n_best most likely seq idx)
slot_score(torch.FloatTensor): bsize x n_best
slot_idx(list): n_best=2, such as [ [[1, 2, 4, 9], [1, 2, 3, 5]] , [[1, 2, 5], [1, 2, 3]] , ... ]
"""
slot_scores, slot_idxs = self.crf_layer._viterbi_decode_nbest(
bios, lens2mask(lens), n_best)
threshold = n_best if intents.size(-1) > 2 * n_best else int(n_best /
2)
intent_scores, intent_idxs = intents.topk(threshold, dim=1)
comb_scores = slot_scores.unsqueeze(-1) + intent_scores.unsqueeze(1)
flat_comb_scores = comb_scores.contiguous().view(
comb_scores.size(0), -1)
_, best_score_id = flat_comb_scores.topk(n_best, 1, True, True)
pick_slots = best_score_id // intent_scores.size(-1) # bsize x n_best
pick_intents = best_score_id - pick_slots * intent_scores.size(-1)
slot_scores = torch.gather(slot_scores, 1, pick_slots)
slot_idxs = [(torch.gather(
b, 0,
pick_slots[idx].unsqueeze(dim=1).repeat(1, b.size(1)))).tolist()
for idx, b in enumerate(slot_idxs)]
intent_scores = torch.gather(intent_scores, 1, pick_intents)
intent_idxs = torch.gather(intent_idxs, 1, pick_intents).tolist()
return {
"intent": (intent_scores, intent_idxs),
"slot": (slot_scores, slot_idxs)
}
