def infer(self, keys, key_mask, values, initial_state, target_embedding,
target_bias, keep_prob):
def infer_step(y_prev, mask, state, keys, values, key_mask, embedding,
embedding_bias):
return self._infer_step(y_prev, mask, state, keys, values,
key_mask, embedding, embedding_bias,
keep_prob)
n_steps, batch_size = key_mask.shape
seq = None
initial_inputs = T.zeros((batch_size, target_embedding.shape[1]),
"float32")
initial_mask = T.ones((batch_size, 1), "float32")
outputs_info = [
initial_inputs, initial_mask, initial_state, None, None
]
non_seq = [keys, values, key_mask, target_embedding, target_bias]
# max length is len_src*3
inputs, mask, states, contexts, probs = ops.scan(infer_step,
seq,
outputs_info,
non_seq,
n_steps=n_steps * 2)
mask = T.reshape(mask, mask.shape[:-1])
mask = T.roll(mask, 1, 0)
mask = T.set_subtensor(mask[0, :], initial_mask[:, 0])
# (step, batch, n_voc)->(step*batch, n_voc)
probs = T.reshape(probs,
(probs.shape[0] * probs.shape[1], probs.shape[2]))
return states, contexts, probs, mask
def decoder(cell, inputs, mask, initial_state, attention_states,
attention_mask, attn_size, dtype=None, scope=None):
input_size, states_size = cell.input_size
output_size = cell.output_size
dtype = dtype or inputs.dtype
# non sequences should passed to scan, DO NOT use closure
def loop_fn(inputs, mask, state, attn_states, attn_mask, m_states):
mask = mask[:, None]
alpha = attention(state, m_states, output_size, attn_size, attn_mask)
context = theano.tensor.sum(alpha[:, :, None] * attn_states, 0)
output, next_state = cell([inputs, context], state)
next_state = (1.0 - mask) * state + mask * next_state
return [next_state, context]
with ops.variable_scope(scope or "decoder"):
mapped_states = map_attention_states(attention_states, states_size,
attn_size)
seq = [inputs, mask]
outputs_info = [initial_state, None]
non_seq = [attention_states, attention_mask, mapped_states]
(states, contexts) = ops.scan(loop_fn, seq, outputs_info, non_seq)
return states, contexts
def decoder(cell,
inputs,
mask,
initial_state,
attention_states,
attention_mask,
attn_size,
mapped_states=None,
dtype=None,
scope=None):
input_size, states_size = cell.input_size
output_size = cell.output_size
dtype = dtype or inputs.dtype
att_size = [output_size, states_size, attn_size]
def loop_fn(inputs, mask, state, attn_states, attn_mask, mapped_states):
mask = mask[:, None]
alpha = attention(state, None, mapped_states, attn_mask, att_size)
context = theano.tensor.sum(alpha[:, :, None] * attn_states, 0)
output, next_state = cell([inputs, context], state)
next_state = (1.0 - mask) * state + mask * next_state
return [next_state, context]
with ops.variable_scope(scope or "decoder"):
if mapped_states is None:
mapped_states = attention(None, attention_states, None, None,
att_size)
seq = [inputs, mask]
outputs_info = [initial_state, None]
non_seq = [attention_states, attention_mask, mapped_states]
(states, contexts) = ops.scan(loop_fn, seq, outputs_info, non_seq)
return states, contexts
def scan(self, y_emb, mask, cwkeys, cpkeys, fwkeys, fpkeys, key_mask, values, initial_state):
"""
build model
:return:
"""
seq = [y_emb, mask]
outputs_info = [initial_state, None, None, None]
non_seq = [cwkeys, cpkeys, fwkeys, fpkeys, values, key_mask]
(states, contexts, y_pos_states, posscores) = ops.scan(self.step, seq, outputs_info, non_seq)
return states, contexts, y_pos_states, posscores
def scan(self, y_emb, mask, keys, key_mask, values, initial_state):
"""
build model
:return:
"""
seq = [y_emb, mask]
outputs_info = [initial_state, None]
non_seq = keys + values + key_mask
(states, contexts) = ops.scan(self.step, seq, outputs_info, non_seq)
return states, contexts
def gru_encoder(cell, inputs, mask, initial_state=None, dtype=None):
#if not isinstance(cell, nn.rnn_cell.gru_cell):
# raise ValueError("only gru_cell is supported")
if isinstance(inputs, (list, tuple)):
raise ValueError("inputs must be a tensor, not list or tuple")
def loop_fn(inputs, mask, state):
mask = mask[:, None]
output, next_state = cell(inputs, state)
next_state = (1.0 - mask) * state + mask * next_state
return next_state
if initial_state is None:
batch = inputs.shape[1]
state_size = cell.state_size
initial_state = theano.tensor.zeros([batch, state_size], dtype=dtype)
seq = [inputs, mask]
states = ops.scan(loop_fn, seq, [initial_state])
return states
def gru_encoder(cell, inputs, mask, initial_state=None, dtype=None):
if not isinstance(cell, nn.rnn_cell.rnn_cell):
raise ValueError("cell is not an instance of rnn_cell")
if isinstance(inputs, (list, tuple)):
raise ValueError("inputs must be a tensor, not list or tuple")
def loop_fn(inputs, mask, state):
mask = mask[:, None]
output, next_state = cell(inputs, state)
next_state = (1.0 - mask) * state + mask * next_state
return next_state
if initial_state is None:
batch = inputs.shape[1]
state_size = cell.state_size
initial_state = theano.tensor.zeros([batch, state_size], dtype=dtype)
seq = [inputs, mask]
# ops.scan is a wrapper of theano.scan, which automatically add updates to
# optimizer, you can set return_updates=True to behave like Theano's scan
states = ops.scan(loop_fn, seq, [initial_state])
return states
