def forward(self, x, y=None, return_probs=False):
# TODO refactor return
seq_len, batch_size = x.size()[0], x.size()[1]
hidden = self.rnn.init_hidden(batch_size)
hidden = repackage_hidden(hidden)
x, hidden, rnn_hs, dropped_rnn_hs = self.rnn(x, hidden, return_h=True)
x = self.dense(x)
probs = self.softmax(x[-1, :, :])
predicted_labels = probs.argmax(-1)
if y is not None:
if self.penalize_all_steps:
x = x.view(-1, self.out_size)
y = y.repeat(seq_len)
else:
x = x[-1, :, :]
loss = self.loss_fn(x, y) + sum(
self.ar_alpha * dropped_rnn_h.pow(2).mean() for dropped_rnn_h in dropped_rnn_hs[-1:])
if return_probs:
return predicted_labels, loss, probs
else:
return predicted_labels, loss
else:
if return_probs:
return predicted_labels, probs
return predicted_labels
def train():
# Turn on training mode which enables dropout.
if args.model == 'QRNN': model.reset()
total_loss = 0
start_time = time.time()
ntokens = len(corpus.dictionary)
hidden = model.init_hidden(args.batch_size)
batch, i = 0, 0
while i < train_data.size(0) - 1 - 1:
bptt = args.bptt if np.random.random() < 0.95 else args.bptt / 2.
# Prevent excessively small or negative sequence lengths
seq_len = max(5, int(np.random.normal(bptt, 5)))
# There's a very small chance that it could select a very long sequence length resulting in OOM
# seq_len = min(seq_len, args.bptt + 10)
lr2 = optimizer.param_groups[0]['lr']
optimizer.param_groups[0]['lr'] = lr2 * seq_len / args.bptt
model.train()
data, targets = get_batch(train_data, i, args, seq_len=seq_len)
# Starting each batch, we detach the hidden state from how it was previously produced.
# If we didn't, the model would try backpropagating all the way to start of the dataset.
hidden = repackage_hidden(hidden)
optimizer.zero_grad()
output, hidden, rnn_hs, dropped_rnn_hs = model(data, hidden, return_h=True)
raw_loss = criterion(model.decoder.weight, model.decoder.bias, output, targets)
loss = raw_loss
# Activiation Regularization
if args.alpha: loss = loss + sum(args.alpha * dropped_rnn_h.pow(2).mean() for dropped_rnn_h in dropped_rnn_hs[-1:])
# Temporal Activation Regularization (slowness)
if args.beta: loss = loss + sum(args.beta * (rnn_h[1:] - rnn_h[:-1]).pow(2).mean() for rnn_h in rnn_hs[-1:])
loss.backward()
# `clip_grad_norm` helps prevent the exploding gradient problem in RNNs / LSTMs.
if args.clip: torch.nn.utils.clip_grad_norm_(params, args.clip)
optimizer.step()
total_loss += raw_loss.data
optimizer.param_groups[0]['lr'] = lr2
if batch % args.log_interval == 0 and batch > 0:
cur_loss = total_loss.item() / args.log_interval
elapsed = time.time() - start_time
print('| epoch {:3d} | {:5d}/{:5d} batches | lr {:05.5f} | ms/batch {:5.2f} | '
'loss {:5.2f} | ppl {:8.2f} | bpc {:8.3f}'.format(
epoch, batch, len(train_data) // args.bptt, optimizer.param_groups[0]['lr'],
elapsed * 1000 / args.log_interval, cur_loss, math.exp(cur_loss), cur_loss / math.log(2)))
total_loss = 0
start_time = time.time()
###
batch += 1
i += seq_len
def evaluate(data_source, batch_size=10):
# Turn on evaluation mode which disables dropout.
model.eval()
if args.model == 'QRNN': model.reset()
total_loss = 0
ntokens = len(corpus.dictionary)
hidden = model.init_hidden(batch_size)
for i in range(0, data_source.size(0) - 1, args.bptt):
data, targets = get_batch(data_source, i, args, evaluation=True)
output, hidden = model(data, hidden)
total_loss += len(data) * criterion(model.decoder.weight, model.decoder.bias, output, targets).data
hidden = repackage_hidden(hidden)
return total_loss.item() / len(data_source)
def evaluate(data_source, batch_size=10, window=args.window):
# Turn on evaluation mode which disables dropout.
if args.model == 'QRNN': model.reset()
model.eval()
total_loss = 0
ntokens = len(corpus.dictionary)
hidden = model.init_hidden(batch_size)
next_word_history = None
pointer_history = None
for i in range(0, data_source.size(0) - 1, args.bptt):
if i > 0: print(i, len(data_source), math.exp(total_loss / i))
data, targets = get_batch(data_source, i, evaluation=True, args=args)
output, hidden, rnn_outs, _ = model(data, hidden, return_h=True)
rnn_out = rnn_outs[-1].squeeze()
output_flat = output.view(-1, ntokens)
###
# Fill pointer history
start_idx = len(
next_word_history) if next_word_history is not None else 0
next_word_history = torch.cat(
[one_hot(t.data[0], ntokens)
for t in targets]) if next_word_history is None else torch.cat([
next_word_history,
torch.cat([one_hot(t.data[0], ntokens) for t in targets])
])
#print(next_word_history)
pointer_history = Variable(
rnn_out.data) if pointer_history is None else torch.cat(
[pointer_history, Variable(rnn_out.data)], dim=0)
#print(pointer_history)
###
# Built-in cross entropy
# total_loss += len(data) * criterion(output_flat, targets).data[0]
###
# Manual cross entropy
# softmax_output_flat = torch.nn.functional.softmax(output_flat)
# soft = torch.gather(softmax_output_flat, dim=1, index=targets.view(-1, 1))
# entropy = -torch.log(soft)
# total_loss += len(data) * entropy.mean().data[0]
###
# Pointer manual cross entropy
loss = 0
softmax_output_flat = torch.nn.functional.softmax(output_flat)
for idx, vocab_loss in enumerate(softmax_output_flat):
p = vocab_loss
if start_idx + idx > window:
valid_next_word = next_word_history[start_idx + idx -
window:start_idx + idx]
valid_pointer_history = pointer_history[start_idx + idx -
window:start_idx + idx]
logits = torch.mv(valid_pointer_history, rnn_out[idx])
theta = args.theta
ptr_attn = torch.nn.functional.softmax(theta * logits).view(
-1, 1)
ptr_dist = (ptr_attn.expand_as(valid_next_word) *
valid_next_word).sum(0).squeeze()
lambdah = args.lambdasm
p = lambdah * ptr_dist + (1 - lambdah) * vocab_loss
###
target_loss = p[targets[idx].data]
loss += (-torch.log(target_loss)).data[0]
total_loss += loss / batch_size
###
hidden = repackage_hidden(hidden)
next_word_history = next_word_history[-window:]
pointer_history = pointer_history[-window:]
return total_loss / len(data_source)