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Paddle/python/paddle/fluid/dygraph/rnn.py

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# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from . import Layer
from ..layers import sigmoid, tanh, concat, fill_constant, matmul, elementwise_add, elementwise_mul, split
import copy
__all__ = ['LSTMCell', 'GRUCell']
class LSTMCell(Layer):
"""
LSTMCell implementation using basic operators.
There are two LSTMCell version, the default one is compatible with CUDNN LSTM implementation.
The algorithm can be described as the equations below.
.. math::
i_t &= sigmoid(W_{ix}x_{t} + W_{ih}h_{t-1} + bx_i + bh_i)
f_t &= sigmoid(W_{fx}x_{t} + W_{fh}h_{t-1} + bx_f + bh_f)
o_t &= sigmoid(W_{ox}x_{t} + W_{oh}h_{t-1} + bx_o + bh_o)
\\tilde{c_t} &= tanh(W_{cx}x_t + W_{ch}h_{t-1} + bx_c + bh_c)
c_t &= f_t \\odot c_{t-1} + i_t \\odot \\tilde{c_t}
h_t &= o_t \\odot tanh(c_t)
The other LSTMCell version is compatible with the BasicLSTMUnit used in static graph.
The algorithm can be described as the equations below.
.. math::
i_t &= sigmoid(W_{ix}x_{t} + W_{ih}h_{t-1} + b_i)
f_t &= sigmoid(W_{fx}x_{t} + W_{fh}h_{t-1} + b_f + forget_bias )
o_t &= sigmoid(W_{ox}x_{t} + W_{oh}h_{t-1} + b_o)
\\tilde{c_t} &= tanh(W_{cx}x_t + W_{ch}h_{t-1} + b_c)
c_t &= f_t \\odot c_{t-1} + i_t \\odot \\tilde{c_t}
h_t &= o_t \\odot tanh(c_t)
Args:
hidden_size (integer): The hidden size used in the Cell.
input_size (integer): The input size used in the Cell.
param_attr(ParamAttr|None): The parameter attribute for the learnable
weight matrix. Note:
If it is set to None or one attribute of ParamAttr, LSTMCell will
create ParamAttr as param_attr. If the Initializer of the param_attr
is not set, the parameter is initialized with Xavier. Default: None.
bias_attr (ParamAttr|None): The parameter attribute for the bias
of LSTMCell.
If it is set to None or one attribute of ParamAttr, LSTMCell will
create ParamAttr as bias_attr. If the Initializer of the bias_attr
is not set, the bias is initialized as zero. Default: None.
gate_activation (function|None): The activation function for gates (actGate).
Default: 'fluid.layers.sigmoid'
activation (function|None): The activation function for cells (actNode).
Default: 'fluid.layers.tanh'
forget_bias(float|1.0): forget bias used when computing forget gate. This
is not used in default LSTMCell implementation (CUDNN compatiable)
use_cudnn_impl(bool|True): whether to use CUDNN compatible LSTMCell
dtype(string): data type used in this cell
Returns:
None
Examples:
.. code-block:: python
from paddle import fluid
import paddle.fluid.core as core
from paddle.fluid.dygraph import LSTMCell
import numpy as np
batch_size = 64
input_size = 128
hidden_size = 256
step_input_np = np.random.uniform(-0.1, 0.1, (
batch_size, input_size)).astype('float64')
pre_hidden_np = np.random.uniform(-0.1, 0.1, (
batch_size, hidden_size)).astype('float64')
pre_cell_np = np.random.uniform(-0.1, 0.1, (
batch_size, hidden_size)).astype('float64')
if core.is_compiled_with_cuda():
place = core.CUDAPlace(0)
else:
place = core.CPUPlace()
with fluid.dygraph.guard(place):
cudnn_lstm = LSTMCell(hidden_size, input_size)
step_input_var = fluid.dygraph.to_variable(step_input_np)
pre_hidden_var = fluid.dygraph.to_variable(pre_hidden_np)
pre_cell_var = fluid.dygraph.to_variable(pre_cell_np)
new_hidden, new_cell = cudnn_lstm(step_input_var, pre_hidden_var, pre_cell_var)
"""
def __init__(self,
hidden_size,
input_size,
param_attr=None,
bias_attr=None,
gate_activation=None,
activation=None,
forget_bias=1.0,
use_cudnn_impl=True,
dtype='float64'):
super(LSTMCell, self).__init__(dtype)
self._hidden_size = hidden_size
self._input_size = input_size
self._param_attr = param_attr
self._bias_attr = bias_attr
self._dtype = dtype
self._gate_activation = gate_activation or sigmoid
self._activation = activation or tanh
self._use_cudnn_impl = use_cudnn_impl
if self._use_cudnn_impl:
if self._param_attr is not None and self._param_attr.name is not None:
weight_ih_param_attr = copy.deepcopy(self._param_attr)
weight_hh_param_attr = copy.deepcopy(self._param_attr)
weight_ih_param_attr.name += "_weight_ih"
weight_hh_param_attr.name += "_weight_hh"
else:
weight_ih_param_attr = self._param_attr
weight_hh_param_attr = self._param_attr
if self._bias_attr is not None and self._bias_attr.name is not None:
bias_ih_param_attr = copy.deepcopy(self._bias_attr)
bias_hh_param_attr = copy.deepcopy(self._bias_attr)
bias_ih_param_attr.name += "_bias_ih"
bias_hh_param_attr.name += "_bias_hh"
else:
bias_ih_param_attr = self._bias_attr
bias_hh_param_attr = self._bias_attr
self._weight_ih = self.create_parameter(
attr=weight_ih_param_attr,
shape=[4 * self._hidden_size, self._input_size],
dtype=self._dtype)
self._weight_hh = self.create_parameter(
attr=weight_hh_param_attr,
shape=[4 * self._hidden_size, self._hidden_size],
dtype=self._dtype)
self._bias_ih = self.create_parameter(
attr=bias_ih_param_attr,
shape=[4 * self._hidden_size],
dtype=self._dtype,
is_bias=True)
self._bias_hh = self.create_parameter(
attr=bias_hh_param_attr,
shape=[4 * self._hidden_size],
dtype=self._dtype,
is_bias=True)
else:
self._forget_bias = fill_constant(
[1], dtype=dtype, value=forget_bias)
self._forget_bias.stop_gradient = False
self._weight = self.create_parameter(
attr=self._param_attr,
shape=[
self._input_size + self._hidden_size, 4 * self._hidden_size
],
dtype=dtype)
self._bias = self.create_parameter(
attr=self._bias_attr,
shape=[4 * self._hidden_size],
dtype=dtype,
is_bias=True)
def forward(self, input, pre_hidden, pre_cell):
if self._use_cudnn_impl:
igates = matmul(input, y=self._weight_ih, transpose_y=True)
igates = elementwise_add(igates, self._bias_ih)
hgates = matmul(pre_hidden, self._weight_hh, transpose_y=True)
hgates = elementwise_add(hgates, self._bias_hh)
chunked_igates = split(igates, num_or_sections=4, dim=1)
chunked_hgates = split(hgates, num_or_sections=4, dim=1)
ingate = elementwise_add(chunked_igates[0], chunked_hgates[0])
ingate = self._gate_activation(ingate)
forgetgate = elementwise_add(chunked_igates[1], chunked_hgates[1])
forgetgate = self._gate_activation(forgetgate)
cellgate = elementwise_add(chunked_igates[2], chunked_hgates[2])
cellgate = self._activation(cellgate)
outgate = elementwise_add(chunked_igates[3], chunked_hgates[3])
outgate = self._gate_activation(outgate)
new_cell = (forgetgate * pre_cell) + (ingate * cellgate)
new_hidden = outgate * self._activation(new_cell)
else:
concat_input_hidden = concat([input, pre_hidden], 1)
gate_input = matmul(x=concat_input_hidden, y=self._weight)
gate_input = elementwise_add(gate_input, self._bias)
i, j, f, o = split(gate_input, num_or_sections=4, dim=-1)
new_cell = elementwise_add(
elementwise_mul(pre_cell,
self._gate_activation(
elementwise_add(f, self._forget_bias))),
elementwise_mul(sigmoid(i), tanh(j)))
new_hidden = self._activation(new_cell) * self._gate_activation(o)
return new_hidden, new_cell
class GRUCell(Layer):
"""
GRU implementation using basic operators.
There are two GRUCell version, the default one is compatible with CUDNN GRU implementation.
The algorithm can be described as the equations below.
.. math::
u_t & = sigmoid(W_{ux} x_{t} + b_ux + W_{uh} h_{t-1} + b_uh)
r_t & = sigmoid(W_{rx} x_{t} + b_rx + W_{rh} h_{t-1} + b_rh)
\\tilde{h_{t}} & = tanh(W_{cx} x_{t} + b_cx + r_t \\odot (W_{ch} h_{t-1} + b_ch))
h_t & = u_t h_{t-1} + (1-u_t) \\tilde{h_{t}}
The other LSTMCell version is compatible with the BasicGRUUnit used in static graph.
The algorithm can be described as the equations below.
.. math::
u_t & = sigmoid(W_{ux} x_{t} + W_{uh} h_{t-1} + b_u)
r_t & = sigmoid(W_{rx} x_{t} + W_{rh} h_{t-1} + b_r)
\\tilde{h_{t}} & = tanh(W_{cx} x_{t} + W_{ch} \\odot(r_t, h_{t-1}) + b_m)
h_t & = u_t h_{t-1} + (1-u_t) \\tilde{h_{t}}
Args:
hidden_size (integer): The hidden size used in the Cell.
input_size (integer): The input size used in the Cell.
param_attr(ParamAttr|None): The parameter attribute for the learnable
weight matrix. Note:
If it is set to None or one attribute of ParamAttr, GRUCell will
create ParamAttr as param_attr. If the Initializer of the param_attr
is not set, the parameter is initialized with Xavier. Default: None.
bias_attr (ParamAttr|None): The parameter attribute for the bias
of GRUCell.
If it is set to None or one attribute of ParamAttr, GRUCell will
create ParamAttr as bias_attr. If the Initializer of the bias_attr
is not set, the bias is initialized zero. Default: None.
gate_activation (function|None): The activation function for gates (actGate).
Default: 'fluid.layers.sigmoid'
activation (function|None): The activation function for cell (actNode).
Default: 'fluid.layers.tanh'
use_cudnn_impl(bool|True): whether to use CUDNN compatible LSTMCell
dtype(string): data type used in this cell
Returns:
None
Examples:
.. code-block:: python
from paddle import fluid
import paddle.fluid.core as core
from paddle.fluid.dygraph import GRUCell
import numpy as np
batch_size = 64
input_size = 128
hidden_size = 256
step_input_np = np.random.uniform(-0.1, 0.1, (
batch_size, input_size)).astype('float64')
pre_hidden_np = np.random.uniform(-0.1, 0.1, (
batch_size, hidden_size)).astype('float64')
if core.is_compiled_with_cuda():
place = core.CUDAPlace(0)
else:
place = core.CPUPlace()
with fluid.dygraph.guard(place):
cudnn_gru = GRUCell(hidden_size, input_size)
step_input_var = fluid.dygraph.to_variable(step_input_np)
pre_hidden_var = fluid.dygraph.to_variable(pre_hidden_np)
"""
def __init__(self,
hidden_size,
input_size,
param_attr=None,
bias_attr=None,
gate_activation=None,
activation=None,
use_cudnn_impl=True,
dtype='float64'):
super(GRUCell, self).__init__()
self._hidden_size = hidden_size
self._input_size = input_size
self._param_attr = param_attr
self._bias_attr = bias_attr
self._dtype = dtype
self._gate_activation = gate_activation or sigmoid
self._activation = activation or tanh
self._use_cudnn_impl = use_cudnn_impl
if self._use_cudnn_impl:
if self._param_attr is not None and self._param_attr.name is not None:
weight_ih_param_attr = copy.deepcopy(self._param_attr)
weight_hh_param_attr = copy.deepcopy(self._param_attr)
weight_ih_param_attr.name += "_weight_ih"
weight_hh_param_attr.name += "_weight_hh"
else:
weight_ih_param_attr = self._param_attr
weight_hh_param_attr = self._param_attr
if self._bias_attr is not None and self._bias_attr.name is not None:
bias_ih_param_attr = copy.deepcopy(self._bias_attr)
bias_hh_param_attr = copy.deepcopy(self._bias_attr)
bias_ih_param_attr.name += "_bias_ih"
bias_hh_param_attr.name += "_bias_hh"
else:
bias_ih_param_attr = self._bias_attr
bias_hh_param_attr = self._bias_attr
self._weight_ih = self.create_parameter(
attr=weight_ih_param_attr,
shape=[3 * self._hidden_size, self._input_size],
dtype=self._dtype)
self._weight_hh = self.create_parameter(
attr=weight_hh_param_attr,
shape=[3 * self._hidden_size, self._hidden_size],
dtype=self._dtype)
self._bias_ih = self.create_parameter(
attr=bias_ih_param_attr,
shape=[3 * self._hidden_size],
dtype=self._dtype,
is_bias=True)
self._bias_hh = self.create_parameter(
attr=bias_hh_param_attr,
shape=[3 * self._hidden_size],
dtype=self._dtype,
is_bias=True)
else:
if self._param_attr is not None and self._param_attr.name is not None:
gate_weight_param_attr = copy.deepcopy(self._param_attr)
candidate_weight_param_attr = copy.deepcopy(self._param_attr)
gate_weight_param_attr.name += "_gate_weight"
candidate_weight_param_attr.name += "_candidate_weight"
else:
gate_weight_param_attr = self._param_attr
candidate_weight_param_attr = self._param_attr
if self._bias_attr is not None and self._bias_attr.name is not None:
gate_bias_param_attr = copy.deepcopy(self._bias_attr)
candidate_bias_param_attr = copy.deepcopy(self._bias_attr)
gate_bias_param_attr.name += "_gate_bias"
candidate_bias_param_attr.name += "_candidate_bias"
else:
gate_bias_param_attr = self._bias_attr
candidate_bias_param_attr = self._bias_attr
self._gate_weight = self.create_parameter(
attr=gate_weight_param_attr,
shape=[
self._input_size + self._hidden_size, 2 * self._hidden_size
],
dtype=dtype)
self._candidate_weight = self.create_parameter(
attr=candidate_weight_param_attr,
shape=[
self._input_size + self._hidden_size, self._hidden_size
],
dtype=dtype)
self._gate_bias = self.create_parameter(
attr=gate_bias_param_attr,
shape=[2 * self._hidden_size],
dtype=dtype,
is_bias=True)
self._candidate_bias = self.create_parameter(
attr=candidate_bias_param_attr,
shape=[self._hidden_size],
dtype=dtype,
is_bias=True)
def forward(self, input, pre_hidden):
if self._use_cudnn_impl:
igates = matmul(input, y=self._weight_ih, transpose_y=True)
igates = elementwise_add(igates, self._bias_ih)
hgates = matmul(pre_hidden, self._weight_hh, transpose_y=True)
hgates = elementwise_add(hgates, self._bias_hh)
chunked_igates = split(igates, num_or_sections=3, dim=1)
chunked_hgates = split(hgates, num_or_sections=3, dim=1)
reset_gate = elementwise_add(chunked_igates[0], chunked_hgates[0])
reset_gate = self._gate_activation(reset_gate)
input_gate = elementwise_add(chunked_igates[1], chunked_hgates[1])
input_gate = self._gate_activation(input_gate)
_temp = reset_gate * chunked_hgates[2]
new_gate = elementwise_add(chunked_igates[2], _temp)
new_gate = self._activation(new_gate)
new_hidden = (pre_hidden - new_gate) * input_gate + new_gate
else:
concat_input_hidden = concat([input, pre_hidden], 1)
gate_input = matmul(x=concat_input_hidden, y=self._gate_weight)
gate_input = elementwise_add(gate_input, self._gate_bias)
gate_input = self._gate_activation(gate_input)
r, u = split(gate_input, num_or_sections=2, dim=1)
r_hidden = r * pre_hidden
candidate = matmul(
concat([input, r_hidden], 1), self._candidate_weight)
candidate = elementwise_add(candidate, self._candidate_bias)
c = self._activation(candidate)
new_hidden = u * pre_hidden + (1 - u) * c
return new_hidden