def conv_lstm_2d(inputs, state, output_channels,
kernel_size=5, name=None, spatial_dims=None):
"""2D Convolutional LSTM."""
input_shape = common_layers.shape_list(inputs)
batch_size, input_channels = input_shape[0], input_shape[-1]
if spatial_dims is None:
input_shape = input_shape[1:]
else:
input_shape = spatial_dims + [input_channels]
cell = contrib.rnn().ConvLSTMCell(
2, input_shape, output_channels, [kernel_size, kernel_size], name=name)
if state is None:
state = cell.zero_state(batch_size, tf.float32)
outputs, new_state = cell(inputs, state)
return outputs, new_state
def build_controller(self):
"""Create the RNN and output projections for controlling the stack.
"""
with tf.name_scope("controller"):
self.rnn = contrib.rnn().BasicRNNCell(self._num_units)
self._input_proj = self.add_variable(
"input_projection_weights",
shape=[self._embedding_size * (self._num_read_heads + 1),
self._num_units],
dtype=self.dtype)
self._input_bias = self.add_variable(
"input_projection_bias",
shape=[self._num_units],
initializer=tf.zeros_initializer(dtype=self.dtype))
self._push_proj, self._push_bias = self.add_scalar_projection(
"push", self._num_write_heads)
self._pop_proj, self._pop_bias = self.add_scalar_projection(
"pop", self._num_write_heads)
self._value_proj, self._value_bias = self.add_vector_projection(
"value", self._num_write_heads)
self._output_proj, self._output_bias = self.add_vector_projection(
"output", 1)
def _rnn(self, inputs, name, initial_state=None, sequence_length=None):
"""A helper method to build tf.nn.dynamic_rnn.
Args:
inputs: The inputs to the RNN. A tensor of shape
[batch_size, max_seq_length, embedding_size]
name: A namespace for the RNN.
initial_state: An optional initial state for the RNN.
sequence_length: An optional sequence length for the RNN.
Returns:
A tf.nn.dynamic_rnn operator.
"""
layers = [self.cell(layer_size)
for layer_size in self._hparams.controller_layer_sizes]
with tf.variable_scope(name):
return tf.nn.dynamic_rnn(
contrib.rnn().MultiRNNCell(layers),
inputs,
initial_state=initial_state,
sequence_length=sequence_length,
dtype=tf.float32,
time_major=False)
