rec/fdeep/layers/bidirectional_layer.hpp
2020-03-18 14:42:46 +08:00

139 lines
5.5 KiB
C++
Executable File

// Copyright 2016, Tobias Hermann.
// https://github.com/Dobiasd/frugally-deep
// Distributed under the MIT License.
// (See accompanying LICENSE file or at
// https://opensource.org/licenses/MIT)
#pragma once
#include "fdeep/layers/layer.hpp"
#include "fdeep/recurrent_ops.hpp"
#include <string>
#include <functional>
namespace fdeep
{
namespace internal
{
class bidirectional_layer : public layer
{
public:
explicit bidirectional_layer(const std::string& name,
const std::string& merge_mode,
const std::size_t n_units,
const std::string& activation,
const std::string& recurrent_activation,
const std::string& wrapped_layer_type,
const bool use_bias,
const bool reset_after,
const bool return_sequences,
const float_vec& forward_weights,
const float_vec& forward_recurrent_weights,
const float_vec& bias_forward,
const float_vec& backward_weights,
const float_vec& backward_recurrent_weights,
const float_vec& bias_backward
)
: layer(name),
merge_mode_(merge_mode),
n_units_(n_units),
activation_(activation),
recurrent_activation_(recurrent_activation),
wrapped_layer_type_(wrapped_layer_type),
use_bias_(use_bias),
reset_after_(reset_after),
return_sequences_(return_sequences),
forward_weights_(forward_weights),
forward_recurrent_weights_(forward_recurrent_weights),
bias_forward_(bias_forward),
backward_weights_(backward_weights),
backward_recurrent_weights_(backward_recurrent_weights),
bias_backward_(bias_backward)
{
}
protected:
tensor5s apply_impl(const tensor5s& inputs) const override final
{
const auto input_shapes = fplus::transform(fplus_c_mem_fn_t(tensor5, shape, shape5), inputs);
// ensure that tensor5 shape is (1, 1, 1, seq_len, n_features)
assertion(inputs.front().shape().size_dim_5_ == 1
&& inputs.front().shape().size_dim_4_ == 1
&& inputs.front().shape().height_ == 1,
"size_dim_5, size_dim_4 and height dimension must be 1, but shape is '" + show_shape5s(input_shapes) + "'");
const auto input = inputs.front();
tensor5s result_forward = {};
tensor5s result_backward = {};
tensor5s bidirectional_result = {};
const tensor5 input_reversed = reverse_time_series_in_tensor5(input);
if (wrapped_layer_type_ == "LSTM")
{
result_forward = lstm_impl(input, n_units_, use_bias_, return_sequences_,
forward_weights_, forward_recurrent_weights_,
bias_forward_, activation_, recurrent_activation_);
result_backward = lstm_impl(input_reversed, n_units_, use_bias_, return_sequences_,
backward_weights_, backward_recurrent_weights_,
bias_backward_, activation_, recurrent_activation_);
}
else if (wrapped_layer_type_ == "GRU")
{
result_forward = gru_impl(input, n_units_, use_bias_, reset_after_, return_sequences_,
forward_weights_, forward_recurrent_weights_,
bias_forward_, activation_, recurrent_activation_);
result_backward = gru_impl(input_reversed, n_units_, use_bias_, reset_after_, return_sequences_,
backward_weights_, backward_recurrent_weights_,
bias_backward_, activation_, recurrent_activation_);
}
else
raise_error("layer '" + wrapped_layer_type_ + "' not yet implemented");
const tensor5 result_backward_reversed = reverse_time_series_in_tensor5(result_backward.front());
if (merge_mode_ == "concat")
{
bidirectional_result = {concatenate_tensor5s_depth({result_forward.front(), result_backward_reversed})};
}
else if (merge_mode_ == "sum")
{
bidirectional_result = {sum_tensor5s({result_forward.front(), result_backward_reversed})};
}
else if (merge_mode_ == "mul")
{
bidirectional_result = {multiply_tensor5s({result_forward.front(), result_backward_reversed})};
}
else if (merge_mode_ == "ave")
{
bidirectional_result = {average_tensor5s({result_forward.front(), result_backward_reversed})};
}
else
raise_error("merge mode '" + merge_mode_ + "' not valid");
return bidirectional_result;
}
const std::string merge_mode_;
const std::size_t n_units_;
const std::string activation_;
const std::string recurrent_activation_;
const std::string wrapped_layer_type_;
const bool use_bias_;
const bool reset_after_;
const bool return_sequences_;
const float_vec forward_weights_;
const float_vec forward_recurrent_weights_;
const float_vec bias_forward_;
const float_vec backward_weights_;
const float_vec backward_recurrent_weights_;
const float_vec bias_backward_;
};
} // namespace internal
} // namespace fdeep