def transduce(self, embed_sent: ExpressionSequence) -> ExpressionSequence:
src = embed_sent.as_tensor()
sent_len = src.dim()[0][1]
batch_size = src.dim()[1]
pad_size = (self.window_receptor -
1) / 2 #TODO adapt it also for even window size
src = dy.concatenate([
dy.zeroes((self.input_dim, pad_size), batch_size=batch_size), src,
dy.zeroes((self.input_dim, pad_size), batch_size=batch_size)
],
d=1)
padded_sent_len = sent_len + 2 * pad_size
conv1 = dy.parameter(self.pConv1)
bias1 = dy.parameter(self.pBias1)
src_chn = dy.reshape(src, (self.input_dim, padded_sent_len, 1),
batch_size=batch_size)
cnn_layer1 = dy.conv2d_bias(src_chn, conv1, bias1, stride=[1, 1])
hidden_layer = dy.reshape(cnn_layer1, (self.internal_dim, sent_len, 1),
batch_size=batch_size)
if self.non_linearity is 'linear':
hidden_layer = hidden_layer
elif self.non_linearity is 'tanh':
hidden_layer = dy.tanh(hidden_layer)
elif self.non_linearity is 'relu':
hidden_layer = dy.rectify(hidden_layer)
elif self.non_linearity is 'sigmoid':
hidden_layer = dy.logistic(hidden_layer)
for conv_hid, bias_hid in self.builder_layers:
hidden_layer = dy.conv2d_bias(hidden_layer,
dy.parameter(conv_hid),
dy.parameter(bias_hid),
stride=[1, 1])
hidden_layer = dy.reshape(hidden_layer,
(self.internal_dim, sent_len, 1),
batch_size=batch_size)
if self.non_linearity is 'linear':
hidden_layer = hidden_layer
elif self.non_linearity is 'tanh':
hidden_layer = dy.tanh(hidden_layer)
elif self.non_linearity is 'relu':
hidden_layer = dy.rectify(hidden_layer)
elif self.non_linearity is 'sigmoid':
hidden_layer = dy.logistic(hidden_layer)
last_conv = dy.parameter(self.last_conv)
last_bias = dy.parameter(self.last_bias)
output = dy.conv2d_bias(hidden_layer,
last_conv,
last_bias,
stride=[1, 1])
output = dy.reshape(output, (sent_len, self.output_dim),
batch_size=batch_size)
output_seq = ExpressionSequence(expr_tensor=output)
self._final_states = [FinalTransducerState(output_seq[-1])]
return output_seq
def transduce(self, es: ExpressionSequence) -> ExpressionSequence:
"""
returns the list of output Expressions obtained by adding the given inputs
to the current state, one by one.
Args:
es: an ExpressionSequence
"""
es_list = [es]
for layer_i, fb in enumerate(self.builder_layers):
reduce_factor = self._reduce_factor_for_layer(layer_i)
if es_list[0].mask is None: mask_out = None
else: mask_out = es_list[0].mask.lin_subsampled(reduce_factor)
if self.downsampling_method == "concat" and len(
es_list[0]) % reduce_factor != 0:
raise ValueError(
f"For 'concat' subsampling, sequence lengths must be multiples of the total reduce factor, "
f"but got sequence length={len(es_list[0])} for reduce_factor={reduce_factor}. "
f"Set Batcher's pad_src_to_multiple argument accordingly.")
fs = fb.transduce(es_list)
if layer_i < len(self.builder_layers) - 1:
if self.downsampling_method == "skip":
es_list = [
ExpressionSequence(expr_list=fs[::reduce_factor],
mask=mask_out)
]
elif self.downsampling_method == "concat":
es_len = len(es_list[0])
es_list_fwd = []
for i in range(0, es_len, reduce_factor):
for j in range(reduce_factor):
if i == 0:
es_list_fwd.append([])
es_list_fwd[j].append(fs[i + j])
es_list = [
ExpressionSequence(expr_list=es_list_fwd[j],
mask=mask_out)
for j in range(reduce_factor)
]
else:
raise RuntimeError(
f"unknown downsampling_method {self.downsampling_method}"
)
else:
# concat final outputs
ret_es = ExpressionSequence(expr_list=[f for f in fs],
mask=mask_out)
self._final_states = [
FinalTransducerState(fb.get_final_states()[0].main_expr(),
fb.get_final_states()[0].cell_expr())
for fb in self.builder_layers
]
return ret_es
def transduce(self, expr_seq: ExpressionSequence) -> ExpressionSequence:
"""
transduce the sequence
Args:
expr_seq: expression sequence or list of expression sequences (where each inner list will be concatenated)
Returns:
expression sequence
"""
Wq, Wk, Wv, Wo = [
dy.parameter(x) for x in (self.pWq, self.pWk, self.pWv, self.pWo)
]
bq, bk, bv, bo = [
dy.parameter(x) for x in (self.pbq, self.pbk, self.pbv, self.pbo)
]
# Start with a [(length, model_size) x batch] tensor
x = expr_seq.as_transposed_tensor()
x_len = x.dim()[0][0]
x_batch = x.dim()[1]
# Get the query key and value vectors
# TODO: do we need bias broadcasting in DyNet?
# q = dy.affine_transform([bq, x, Wq])
# k = dy.affine_transform([bk, x, Wk])
# v = dy.affine_transform([bv, x, Wv])
q = bq + x * Wq
k = bk + x * Wk
v = bv + x * Wv
# Split to batches [(length, head_dim) x batch * num_heads] tensor
q, k, v = [
dy.reshape(x, (x_len, self.head_dim),
batch_size=x_batch * self.num_heads) for x in (q, k, v)
]
# Do scaled dot product [(length, length) x batch * num_heads], rows are queries, columns are keys
attn_score = q * dy.transpose(k) / sqrt(self.head_dim)
if expr_seq.mask is not None:
mask = dy.inputTensor(np.repeat(
expr_seq.mask.np_arr, self.num_heads, axis=0).transpose(),
batched=True) * -1e10
attn_score = attn_score + mask
attn_prob = dy.softmax(attn_score, d=1)
# Reduce using attention and resize to match [(length, model_size) x batch]
o = dy.reshape(attn_prob * v, (x_len, self.input_dim),
batch_size=x_batch)
# Final transformation
# o = dy.affine_transform([bo, attn_prob * v, Wo])
o = bo + o * Wo
expr_seq = ExpressionSequence(expr_transposed_tensor=o,
mask=expr_seq.mask)
self._final_states = [FinalTransducerState(expr_seq[-1], None)]
return expr_seq
def transduce(self, es: ExpressionSequence) -> ExpressionSequence:
"""
returns the list of output Expressions obtained by adding the given inputs
to the current state, one by one, to both the forward and backward RNNs,
and concatenating.
Args:
es: an ExpressionSequence
"""
es_list = [es]
for layer_i, (fb, bb) in enumerate(self.builder_layers):
reduce_factor = self._reduce_factor_for_layer(layer_i)
if es_list[0].mask is None: mask_out = None
else: mask_out = es_list[0].mask.lin_subsampled(reduce_factor)
if self.downsampling_method=="concat" and len(es_list[0]) % reduce_factor != 0:
raise ValueError(f"For 'concat' subsampling, sequence lengths must be multiples of the total reduce factor, "
f"but got sequence length={len(es_list[0])} for reduce_factor={reduce_factor}. "
f"Set Batcher's pad_src_to_multiple argument accordingly.")
fs = fb.transduce(es_list)
bs = bb.transduce([ReversedExpressionSequence(es_item) for es_item in es_list])
if layer_i < len(self.builder_layers) - 1:
if self.downsampling_method=="skip":
es_list = [ExpressionSequence(expr_list=fs[::reduce_factor], mask=mask_out),
ExpressionSequence(expr_list=bs[::reduce_factor][::-1], mask=mask_out)]
elif self.downsampling_method=="concat":
es_len = len(es_list[0])
es_list_fwd = []
es_list_bwd = []
for i in range(0, es_len, reduce_factor):
for j in range(reduce_factor):
if i==0:
es_list_fwd.append([])
es_list_bwd.append([])
es_list_fwd[j].append(fs[i+j])
es_list_bwd[j].append(bs[len(es_list[0])-reduce_factor+j-i])
es_list = [ExpressionSequence(expr_list=es_list_fwd[j], mask=mask_out) for j in range(reduce_factor)] + \
[ExpressionSequence(expr_list=es_list_bwd[j], mask=mask_out) for j in range(reduce_factor)]
else:
raise RuntimeError(f"unknown downsampling_method {self.downsampling_method}")
else:
# concat final outputs
ret_es = ExpressionSequence(
expr_list=[dy.concatenate([f, b]) for f, b in zip(fs, ReversedExpressionSequence(bs))], mask=mask_out)
self._final_states = [FinalTransducerState(dy.concatenate([fb.get_final_states()[0].main_expr(),
bb.get_final_states()[0].main_expr()]),
dy.concatenate([fb.get_final_states()[0].cell_expr(),
bb.get_final_states()[0].cell_expr()])) \
for (fb, bb) in self.builder_layers]
return ret_es
def transduce(self, src: ExpressionSequence) -> ExpressionSequence:
sent_len = len(src)
embeddings = dy.strided_select(dy.parameter(self.embedder), [1,1], [0,0], [self.input_dim, sent_len])
if self.op == 'sum':
output = embeddings + src.as_tensor()
elif self.op == 'concat':
output = dy.concatenate([embeddings, src.as_tensor()])
else:
raise ValueError(f'Illegal op {op} in PositionalTransducer (options are "sum"/"concat")')
output_seq = ExpressionSequence(expr_tensor=output, mask=src.mask)
self._final_states = [FinalTransducerState(output_seq[-1])]
return output_seq