path: root/compiler/luci-interpreter/src/kernels/UnidirectionalSequenceLSTM.cpp

/*
 * Copyright (c) 2022 Samsung Electronics Co., Ltd. All Rights Reserved
 * Copyright 2017 The TensorFlow 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.
 */

#include "kernels/UnidirectionalSequenceLSTM.h"
#include "kernels/Utils.h"

#include <tensorflow/lite/kernels/internal/tensor_utils.h>

namespace luci_interpreter
{
namespace kernels
{
namespace lstm
{
namespace
{

using namespace tflite;

void UpdateLstmCellFloat(int n_batch, int n_cell, float *cell_state, const float *input_gate,
                         float *forget_gate, const float *cell_gate, bool use_cifg, float clip)
{
// NOTE tflite source is as is but will fail build with gcc-8 and above
// TODO remove #pragma
#pragma GCC diagnostic ignored "-Wrestrict"
  tensor_utils::VectorVectorCwiseProduct(forget_gate, cell_state, n_batch * n_cell, cell_state);

  if (use_cifg)
  {
    // With CIFG, input_gate = 1-forget_gate. Use the forget_gate array as
    // scratch, as input_gate array is not allocated in this case. (Be careful
    // not to write to the scratch before reading the forget gate data.)
    float *scratch = forget_gate;
    tensor_utils::Sub1Vector(forget_gate, n_batch * n_cell, scratch);
    tensor_utils::VectorVectorCwiseProductAccumulate(cell_gate, scratch, n_batch * n_cell,
                                                     cell_state);
  }
  else
  {
    tensor_utils::VectorVectorCwiseProductAccumulate(cell_gate, input_gate, n_batch * n_cell,
                                                     cell_state);
  }
  if (clip > 0.0f)
  {
    tensor_utils::CwiseClipping(cell_state, n_batch * n_cell, clip);
  }
}

void CalculateLstmOutputFloat(int n_batch, int n_cell, int n_output, const float *cell_state,
                              const float *output_gate, TfLiteFusedActivation activation,
                              const float *projection_weights, const float *projection_bias,
                              const float proj_clip, float *output_state, float *scratch)
{
  tensor_utils::ApplyActivationToVector(cell_state, n_batch * n_cell, activation, scratch);
  tensor_utils::VectorVectorCwiseProduct(output_gate, scratch, n_batch * n_cell, scratch);

  const bool use_projection = (projection_weights != nullptr);
  const bool use_projection_bias = (projection_bias != nullptr);

  if (use_projection)
  {
    if (use_projection_bias)
    {
      tensor_utils::VectorBatchVectorAssign(projection_bias, n_output, n_batch, output_state);
    }
    else
    {
      std::fill_n(output_state, n_batch * n_output, 0.0f);
    }
    tensor_utils::MatrixBatchVectorMultiplyAccumulate(projection_weights, n_output, n_cell, scratch,
                                                      n_batch, output_state);
    if (proj_clip > 0.0f)
    {
      tensor_utils::CwiseClipping(output_state, n_batch * n_output, proj_clip);
    }
  }
  else
  {
    std::copy_n(scratch, n_batch * n_output, output_state);
  }
}

inline void CalculateLstmGateFloat(const float *input, const float *input_to_gate_weights,
                                   const float *aux_input, const float *aux_input_to_gate_weights,
                                   const float *output_state,
                                   const float *recurrent_to_gate_weights, const float *cell_state,
                                   const float *cell_to_gate_weights,
                                   const float *layer_norm_coefficients, const float *gate_bias,
                                   const int n_batch, const int n_input, const int n_aux_input,
                                   const int n_output, const int n_cell,
                                   const TfLiteFusedActivation activation, float *gate,
                                   const bool is_input_all_zeros, const bool is_aux_input_all_zeros)
{
  const bool use_peephole = (cell_to_gate_weights != nullptr);
  const bool use_layer_norm = (layer_norm_coefficients != nullptr);

  // Initialize scratch buffers with bias for regular lstm or initialize with
  // zero for layer norm lstm.
  if (use_layer_norm)
  {
    std::fill_n(gate, n_cell * n_batch, 0.0f);
  }
  else
  {
    tensor_utils::VectorBatchVectorAssign(gate_bias, n_cell, n_batch, gate);
  }
  // For each batch and cell: compute input_weight * input.
  // Skip if input is all zeros.
  if (!is_input_all_zeros)
  {
    tensor_utils::MatrixBatchVectorMultiplyAccumulate(input_to_gate_weights, n_cell, n_input, input,
                                                      n_batch, gate);
  }
  // For each batch and cell: compute aux_input_weight * aux_input.
  // Skip if auxiliary input is not available or all zeros.
  if (!is_aux_input_all_zeros)
  {
    tensor_utils::MatrixBatchVectorMultiplyAccumulate(aux_input_to_gate_weights, n_cell,
                                                      n_aux_input, aux_input, n_batch, gate);
  }
  // For each batch and cell: compute recurrent_weight * output_state.
  tensor_utils::MatrixBatchVectorMultiplyAccumulate(recurrent_to_gate_weights, n_cell, n_output,
                                                    output_state, n_batch, gate);
  // For each batch and cell: compute cell_weight .* cell_state (peephole LSTM)
  if (use_peephole)
  {
    tensor_utils::VectorBatchVectorCwiseProductAccumulate(cell_to_gate_weights, n_cell, cell_state,
                                                          n_batch, gate);
  }
  // Do layer normalization (if layer norm LSTM)
  if (use_layer_norm)
  {
    tensor_utils::MeanStddevNormalization(gate, gate, n_cell, n_batch);
    tensor_utils::VectorBatchVectorCwiseProduct(layer_norm_coefficients, n_cell, gate, n_batch,
                                                gate);
    tensor_utils::VectorBatchVectorAdd(gate_bias, n_cell, n_batch, gate);
  }
  // Apply activation
  tensor_utils::ApplyActivationToVector(gate, n_batch * n_cell, activation, gate);
}

inline void LstmStepFloat(
  const float *input_ptr, const float *input_to_input_weights_ptr,
  const float *input_to_forget_weights_ptr, const float *input_to_cell_weights_ptr,
  const float *input_to_output_weights_ptr, const float *aux_input_ptr,
  const float *aux_input_to_input_weights_ptr, const float *aux_input_to_forget_weights_ptr,
  const float *aux_input_to_cell_weights_ptr, const float *aux_input_to_output_weights_ptr,
  const float *recurrent_to_input_weights_ptr, const float *recurrent_to_forget_weights_ptr,
  const float *recurrent_to_cell_weights_ptr, const float *recurrent_to_output_weights_ptr,
  const float *cell_to_input_weights_ptr, const float *cell_to_forget_weights_ptr,
  const float *cell_to_output_weights_ptr, const float *input_layer_norm_coefficients_ptr,
  const float *forget_layer_norm_coefficients_ptr, const float *cell_layer_norm_coefficients_ptr,
  const float *output_layer_norm_coefficients_ptr, const float *input_gate_bias_ptr,
  const float *forget_gate_bias_ptr, const float *cell_gate_bias_ptr,
  const float *output_gate_bias_ptr, const float *projection_weights_ptr,
  const float *projection_bias_ptr, const TfLiteLSTMParams *params, int n_batch, int n_cell,
  int n_input, int n_aux_input, int n_output, int output_batch_leading_dim, float *output_state_ptr,
  float *cell_state_ptr, float *scratch0, float *scratch1, float *scratch2, float *scratch3,
  float *output_ptr)
{
  // Since we have already checked that weights are all there or none, we can
  // check the existence of only one to the get the condition.
  const bool use_cifg = (input_to_input_weights_ptr == nullptr);

  // Make named scratch buffers.
  float *input_gate_scratch = scratch0;
  float *forget_gate_scratch = scratch1;
  float *cell_gate_scratch = scratch2;
  float *output_gate_scratch = scratch3;

  // Check if inputs are all zeros so we can skip some computations.
  const bool is_input_all_zeros = tensor_utils::IsZeroVector(input_ptr, n_batch * n_input);
  const bool is_aux_input_all_zeros =
    (aux_input_ptr == nullptr || tensor_utils::IsZeroVector(aux_input_ptr, n_batch * n_aux_input));
  if (!use_cifg)
  {
    // Calculate the input gate. (If not CIFG.)
    CalculateLstmGateFloat(input_ptr, input_to_input_weights_ptr, aux_input_ptr,
                           aux_input_to_input_weights_ptr, output_state_ptr,
                           recurrent_to_input_weights_ptr, cell_state_ptr,
                           cell_to_input_weights_ptr, input_layer_norm_coefficients_ptr,
                           input_gate_bias_ptr, n_batch, n_input, n_aux_input, n_output, n_cell,
                           /*activation=*/kTfLiteActSigmoid, input_gate_scratch, is_input_all_zeros,
                           is_aux_input_all_zeros);
  }
  // Calculate the forget gate.
  CalculateLstmGateFloat(input_ptr, input_to_forget_weights_ptr, aux_input_ptr,
                         aux_input_to_forget_weights_ptr, output_state_ptr,
                         recurrent_to_forget_weights_ptr, cell_state_ptr,
                         cell_to_forget_weights_ptr, forget_layer_norm_coefficients_ptr,
                         forget_gate_bias_ptr, n_batch, n_input, n_aux_input, n_output, n_cell,
                         /*activation=*/kTfLiteActSigmoid, forget_gate_scratch, is_input_all_zeros,
                         is_aux_input_all_zeros);
  // Calculate the cell update gate.
  CalculateLstmGateFloat(
    input_ptr, input_to_cell_weights_ptr, aux_input_ptr, aux_input_to_cell_weights_ptr,
    output_state_ptr, recurrent_to_cell_weights_ptr, /*cell_state=*/nullptr,
    /*cell_to_gate_weights=*/nullptr, cell_layer_norm_coefficients_ptr, cell_gate_bias_ptr, n_batch,
    n_input, n_aux_input, n_output, n_cell, params->activation, cell_gate_scratch,
    is_input_all_zeros, is_aux_input_all_zeros);
  // Update the cell state.
  UpdateLstmCellFloat(n_batch, n_cell, cell_state_ptr, input_gate_scratch, forget_gate_scratch,
                      cell_gate_scratch, use_cifg, params->cell_clip);
  // Calculate output gate.
  CalculateLstmGateFloat(input_ptr, input_to_output_weights_ptr, aux_input_ptr,
                         aux_input_to_output_weights_ptr, output_state_ptr,
                         recurrent_to_output_weights_ptr, cell_state_ptr,
                         cell_to_output_weights_ptr, output_layer_norm_coefficients_ptr,
                         output_gate_bias_ptr, n_batch, n_input, n_aux_input, n_output, n_cell,
                         /*activation=*/kTfLiteActSigmoid, output_gate_scratch, is_input_all_zeros,
                         is_aux_input_all_zeros);
  // Update the output state.
  CalculateLstmOutputFloat(n_batch, n_cell, n_output, cell_state_ptr, output_gate_scratch,
                           params->activation, projection_weights_ptr, projection_bias_ptr,
                           params->proj_clip, output_state_ptr, scratch2);
  // Copy output state to the output. Note that the output's rows may not be
  // contiguous (output_batch_leading_dim != n_output).
  for (int b = 0; b < n_batch; b++)
  {
    std::copy_n(output_state_ptr + b * n_output, n_output,
                output_ptr + b * output_batch_leading_dim);
  }
}

} // namespace

void EvalFloat(const Tensor *input,

               const Tensor *input_to_input_weights, const Tensor *input_to_forget_weights,
               const Tensor *input_to_cell_weights, const Tensor *input_to_output_weights,

               const Tensor *recurrent_to_input_weights, const Tensor *recurrent_to_forget_weights,
               const Tensor *recurrent_to_cell_weights, const Tensor *recurrent_to_output_weights,

               const Tensor *cell_to_input_weights, const Tensor *cell_to_forget_weights,
               const Tensor *cell_to_output_weights,

               const Tensor *input_layer_norm_coefficients,
               const Tensor *forget_layer_norm_coefficients,
               const Tensor *cell_layer_norm_coefficients,
               const Tensor *output_layer_norm_coefficients,

               const Tensor *aux_input, const Tensor *aux_input_to_input_weights,
               const Tensor *aux_input_to_forget_weights, const Tensor *aux_input_to_cell_weights,
               const Tensor *aux_input_to_output_weights,

               const Tensor *input_gate_bias, const Tensor *forget_gate_bias,
               const Tensor *cell_gate_bias, const Tensor *output_gate_bias,

               const Tensor *projection_weights, const Tensor *projection_bias,
               const TfLiteLSTMParams *params,

               bool forward_sequence, bool time_major, int output_offset,

               Tensor *scratch_buffer, Tensor *output_state, Tensor *cell_state, Tensor *output)
{
  const Shape &input_shape = input->shape();
  assert(input_shape.num_dims() >= 2 && input_shape.num_dims() <= 3);
  int max_time, n_batch;
  if (input_shape.num_dims() == 3)
  {
    max_time = (time_major) ? input_shape.dim(0) : input_shape.dim(1);
    n_batch = (time_major) ? input_shape.dim(1) : input_shape.dim(0);
  }
  else
  {
    max_time = 1;
    n_batch = input_shape.dim(0);
  }
  const int n_input = input_shape.dim(input_shape.num_dims() - 1);

  int aux_input_temp = 0;
  if (aux_input)
  {
    const Shape &aux_input_shape = aux_input->shape();
    aux_input_temp = aux_input_shape.dim(aux_input_shape.num_dims() - 1);
  }
  const int aux_input_size = aux_input_temp;

  // n_cell and n_output will be the same size when there is no projection.
  const Shape &input_to_output_weights_shape = input_to_output_weights->shape();
  const Shape &recurrent_to_output_weights_shape = recurrent_to_output_weights->shape();
  const int n_cell = input_to_output_weights_shape.dim(0);
  const int n_output = recurrent_to_output_weights_shape.dim(1);

  // Since we have already checked that weights are all there or none, we can
  // check the existence of only one to the get the condition.
  const bool use_cifg = (input_to_input_weights == nullptr);

  // Index the scratch buffers pointers to the global scratch buffer.
  float *scratch_buffer_ptr = getTensorData<float>(scratch_buffer);
  float *input_gate_scratch = nullptr;
  float *cell_gate_scratch = nullptr;
  float *forget_gate_scratch = nullptr;
  float *output_gate_scratch = nullptr;
  if (use_cifg)
  {
    cell_gate_scratch = scratch_buffer_ptr;
    forget_gate_scratch = scratch_buffer_ptr + n_cell * n_batch;
    output_gate_scratch = scratch_buffer_ptr + 2 * n_cell * n_batch;
  }
  else
  {
    input_gate_scratch = scratch_buffer_ptr;
    cell_gate_scratch = scratch_buffer_ptr + n_cell * n_batch;
    forget_gate_scratch = scratch_buffer_ptr + 2 * n_cell * n_batch;
    output_gate_scratch = scratch_buffer_ptr + 3 * n_cell * n_batch;
  }

  const Shape &output_shape = output->shape();
  const int output_batch_leading_dim = output_shape.dim(output_shape.num_dims() - 1);
  if (time_major)
  {
    // Loop through the sequence.
    const int input_step = n_batch * n_input;
    const int output_step = n_batch * output_batch_leading_dim;
    for (int t = 0; t < max_time; t++)
    {
      // If this is the forward_sequence, step forward, otherwise step
      // backwards.
      const int t_rel = forward_sequence ? t : max_time - t - 1;
      const float *input_ptr = getTensorData<float>(input) + t_rel * input_step;
      const float *aux_input_ptr = nullptr;
      if (aux_input)
      {
        aux_input_ptr = getTensorData<float>(aux_input) + t_rel * input_step;
      }
      float *output_ptr = getTensorData<float>(output) + t_rel * output_step + output_offset;

      LstmStepFloat(
        input_ptr, getTensorData<float>(input_to_input_weights),
        getTensorData<float>(input_to_forget_weights), getTensorData<float>(input_to_cell_weights),
        getTensorData<float>(input_to_output_weights), aux_input_ptr,
        getTensorData<float>(aux_input_to_input_weights),
        getTensorData<float>(aux_input_to_forget_weights),
        getTensorData<float>(aux_input_to_cell_weights),
        getTensorData<float>(aux_input_to_output_weights),
        getTensorData<float>(recurrent_to_input_weights),
        getTensorData<float>(recurrent_to_forget_weights),
        getTensorData<float>(recurrent_to_cell_weights),
        getTensorData<float>(recurrent_to_output_weights),
        getTensorData<float>(cell_to_input_weights), getTensorData<float>(cell_to_forget_weights),
        getTensorData<float>(cell_to_output_weights),
        getTensorData<float>(input_layer_norm_coefficients),
        getTensorData<float>(forget_layer_norm_coefficients),
        getTensorData<float>(cell_layer_norm_coefficients),
        getTensorData<float>(output_layer_norm_coefficients), getTensorData<float>(input_gate_bias),
        getTensorData<float>(forget_gate_bias), getTensorData<float>(cell_gate_bias),
        getTensorData<float>(output_gate_bias), getTensorData<float>(projection_weights),
        getTensorData<float>(projection_bias), params, n_batch, n_cell, n_input, aux_input_size,
        n_output, output_batch_leading_dim, getTensorData<float>(output_state),
        getTensorData<float>(cell_state), input_gate_scratch, forget_gate_scratch,
        cell_gate_scratch, output_gate_scratch, output_ptr);
    }
  }
  else
  {
    for (int b = 0; b < n_batch; b++)
    {
      const int input_step = n_input;
      const int output_step = output_batch_leading_dim;
      for (int t = 0; t < max_time; t++)
      {
        // If this is the forward_sequence, step forward, otherwise step
        // backwards.
        const int t_rel = forward_sequence ? t : max_time - t - 1;
        const int time_offset = b * max_time + t_rel;
        const float *input_ptr = getTensorData<float>(input) + time_offset * input_step;
        const float *aux_input_ptr = nullptr;
        if (aux_input)
        {
          aux_input_ptr = getTensorData<float>(aux_input) + time_offset * input_step;
        }
        float *output_ptr =
          getTensorData<float>(output) + time_offset * output_step + output_offset;

        // Offset the {output,cell}_state pointers to the right batch.
        float *output_state_ptr = getTensorData<float>(output_state) + b * output_batch_leading_dim;
        float *cell_state_ptr = getTensorData<float>(cell_state) + b * n_cell;
        // Offset the scratch pointers to the right batch.
        float *input_gate_scratch_ptr =
          input_gate_scratch ? input_gate_scratch + b * n_cell : nullptr;
        float *forget_gate_scratch_ptr = forget_gate_scratch + b * n_cell;
        float *cell_gate_scratch_ptr = cell_gate_scratch + b * n_cell;
        float *output_gate_scratch_ptr = output_gate_scratch + b * n_cell;

        LstmStepFloat(
          input_ptr, getTensorData<float>(input_to_input_weights),
          getTensorData<float>(input_to_forget_weights),
          getTensorData<float>(input_to_cell_weights),
          getTensorData<float>(input_to_output_weights), aux_input_ptr,
          getTensorData<float>(aux_input_to_input_weights),
          getTensorData<float>(aux_input_to_forget_weights),
          getTensorData<float>(aux_input_to_cell_weights),
          getTensorData<float>(aux_input_to_output_weights),
          getTensorData<float>(recurrent_to_input_weights),
          getTensorData<float>(recurrent_to_forget_weights),
          getTensorData<float>(recurrent_to_cell_weights),
          getTensorData<float>(recurrent_to_output_weights),
          getTensorData<float>(cell_to_input_weights), getTensorData<float>(cell_to_forget_weights),
          getTensorData<float>(cell_to_output_weights),
          getTensorData<float>(input_layer_norm_coefficients),
          getTensorData<float>(forget_layer_norm_coefficients),
          getTensorData<float>(cell_layer_norm_coefficients),
          getTensorData<float>(output_layer_norm_coefficients),
          getTensorData<float>(input_gate_bias), getTensorData<float>(forget_gate_bias),
          getTensorData<float>(cell_gate_bias), getTensorData<float>(output_gate_bias),
          getTensorData<float>(projection_weights), getTensorData<float>(projection_bias), params,
          /*n_batch=*/1, n_cell, n_input, aux_input_size, n_output, output_batch_leading_dim,
          output_state_ptr, cell_state_ptr, input_gate_scratch_ptr, forget_gate_scratch_ptr,
          cell_gate_scratch_ptr, output_gate_scratch_ptr, output_ptr);
      }
    }
  }
}

} // namespace lstm
} // namespace kernels
} // namespace luci_interpreter

namespace luci_interpreter
{
namespace kernels
{

UnidirectionalSequenceLSTM::UnidirectionalSequenceLSTM(
  const Tensor *input,

  const Tensor *input_to_input_weights, const Tensor *input_to_forget_weights,
  const Tensor *input_to_cell_weights, const Tensor *input_to_output_weights,

  const Tensor *recurrent_to_input_weights, const Tensor *recurrent_to_forget_weights,
  const Tensor *recurrent_to_cell_weights, const Tensor *recurrent_to_output_weights,

  const Tensor *cell_to_input_weights, const Tensor *cell_to_forget_weights,
  const Tensor *cell_to_output_weights,

  const Tensor *input_gate_bias, const Tensor *forget_gate_bias, const Tensor *cell_gate_bias,
  const Tensor *output_gate_bias,

  const Tensor *projection_weights, const Tensor *projection_bias,

  const Tensor *output_state, const Tensor *cell_state, const Tensor *input_layer_norm_coefficients,
  const Tensor *forget_layer_norm_coefficients, const Tensor *cell_layer_norm_coefficients,
  const Tensor *output_layer_norm_coefficients,

  Tensor *output, Tensor *scratchpad_1, Tensor *scratchpad_2, Tensor *scratchpad_3,
  const UnidirectionalSequenceLSTMParams &params)
  : KernelWithParams<UnidirectionalSequenceLSTMParams>(
      {input,
       input_to_input_weights,
       input_to_forget_weights,
       input_to_cell_weights,
       input_to_output_weights,

       recurrent_to_input_weights,
       recurrent_to_forget_weights,
       recurrent_to_cell_weights,
       recurrent_to_output_weights,

       cell_to_input_weights,
       cell_to_forget_weights,
       cell_to_output_weights,

       input_gate_bias,
       forget_gate_bias,
       cell_gate_bias,
       output_gate_bias,

       projection_weights,
       projection_bias,

       output_state,
       cell_state,

       input_layer_norm_coefficients,
       forget_layer_norm_coefficients,
       cell_layer_norm_coefficients,
       output_layer_norm_coefficients},
      {output, scratchpad_1, scratchpad_2, scratchpad_3}, params)
{
  // Do nothing
}

// Check that input tensor dimensions matches with each other.
void UnidirectionalSequenceLSTM::check_input_tensor_dimensions(int n_input, int n_output,
                                                               int n_cell, bool use_layer_norm,
                                                               bool is_integer)
{
  // Making sure clipping parameters have valid values.
  // == 0 means no clipping
  //  > 0 means clipping
  LUCI_INTERPRETER_CHECK(params().cell_clip >= 0);
  LUCI_INTERPRETER_CHECK(params().proj_clip >= 0);

  if (input_to_input_weights() != nullptr)
  {
    const Shape &input_to_input_weights_shape = input_to_input_weights()->shape();
    LUCI_INTERPRETER_CHECK(input_to_input_weights_shape.num_dims() == 2);
    LUCI_INTERPRETER_CHECK(input_to_input_weights_shape.dim(0) == n_cell);
    LUCI_INTERPRETER_CHECK(input_to_input_weights_shape.dim(1) == n_input);
  }

  const Shape &input_to_forget_weights_shape = input_to_forget_weights()->shape();
  LUCI_INTERPRETER_CHECK(input_to_forget_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(input_to_forget_weights_shape.dim(0) == n_cell);
  LUCI_INTERPRETER_CHECK(input_to_forget_weights_shape.dim(1) == n_input);

  const Shape &input_to_cell_weights_shape = input_to_cell_weights()->shape();
  LUCI_INTERPRETER_CHECK(input_to_cell_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(input_to_cell_weights_shape.dim(0) == n_cell);
  LUCI_INTERPRETER_CHECK(input_to_cell_weights_shape.dim(1) == n_input);

  if (recurrent_to_input_weights() != nullptr)
  {
    const Shape &recurrent_to_input_weights_shape = recurrent_to_input_weights()->shape();
    LUCI_INTERPRETER_CHECK(recurrent_to_input_weights_shape.num_dims() == 2);
    LUCI_INTERPRETER_CHECK(recurrent_to_input_weights_shape.dim(0) == n_cell);
    LUCI_INTERPRETER_CHECK(recurrent_to_input_weights_shape.dim(1) == n_output);
  }

  const Shape &recurrent_to_forget_weights_shape = recurrent_to_forget_weights()->shape();
  LUCI_INTERPRETER_CHECK(recurrent_to_forget_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(recurrent_to_forget_weights_shape.dim(0) == n_cell);
  LUCI_INTERPRETER_CHECK(recurrent_to_forget_weights_shape.dim(1) == n_output);

  const Shape &recurrent_to_cell_weights_shape = recurrent_to_cell_weights()->shape();
  LUCI_INTERPRETER_CHECK(recurrent_to_cell_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(recurrent_to_cell_weights_shape.dim(0) == n_cell);
  LUCI_INTERPRETER_CHECK(recurrent_to_cell_weights_shape.dim(1) == n_output);

  // We make sure the input-gate's parameters are either both present (regular
  // LSTM) or not at all (CIFG-LSTM).
  const bool cifg_weights_all_or_none =
    ((input_to_input_weights() != nullptr) && (recurrent_to_input_weights() != nullptr)) ||
    ((input_to_input_weights() == nullptr) && (recurrent_to_input_weights() == nullptr));
  LUCI_INTERPRETER_CHECK(cifg_weights_all_or_none == true);

  if (cell_to_input_weights() != nullptr)
  {
    const Shape &cell_to_input_weights_shape = cell_to_input_weights()->shape();
    LUCI_INTERPRETER_CHECK(cell_to_input_weights_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(cell_to_input_weights_shape.dim(0) == n_cell);
    LUCI_INTERPRETER_CHECK(is_integer
                             ? cell_to_input_weights()->element_type() == loco::DataType::S16
                             : cell_to_input_weights()->element_type() ==
                                 input_to_forget_weights()->element_type());
  }

  if (cell_to_forget_weights() != nullptr)
  {
    const Shape &cell_to_forget_weights_shape = cell_to_forget_weights()->shape();
    LUCI_INTERPRETER_CHECK(cell_to_forget_weights_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(cell_to_forget_weights_shape.dim(0) == n_cell);
    LUCI_INTERPRETER_CHECK(is_integer
                             ? cell_to_forget_weights()->element_type() == loco::DataType::S16
                             : cell_to_forget_weights()->element_type() ==
                                 input_to_forget_weights()->element_type());
  }

  if (cell_to_output_weights() != nullptr)
  {
    const Shape &cell_to_output_weights_shape = cell_to_output_weights()->shape();
    LUCI_INTERPRETER_CHECK(cell_to_output_weights_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(cell_to_output_weights_shape.dim(0) == n_cell);
    LUCI_INTERPRETER_CHECK(is_integer
                             ? cell_to_output_weights()->element_type() == loco::DataType::S16
                             : cell_to_output_weights()->element_type() ==
                                 input_to_forget_weights()->element_type());
  }

  // Making sure the peephole weights are there all or none.
  const bool use_cifg = (input_to_input_weights() == nullptr);
  const bool peephole_weights_all_or_none =
    ((cell_to_input_weights() != nullptr || use_cifg) && (cell_to_forget_weights() != nullptr) &&
     (cell_to_output_weights() != nullptr)) ||
    ((cell_to_input_weights() == nullptr) && (cell_to_forget_weights() == nullptr) &&
     (cell_to_output_weights() == nullptr));
  LUCI_INTERPRETER_CHECK(peephole_weights_all_or_none == true);

  // Make sure the input gate bias is present only when not a CIFG-LSTM.
  if (use_cifg)
  {
    LUCI_INTERPRETER_CHECK(input_gate_bias() == nullptr);
  }
  else
  {
    const Shape &input_gate_bias_shape = input_gate_bias()->shape();
    LUCI_INTERPRETER_CHECK(input_gate_bias_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(input_gate_bias_shape.dim(0) == n_cell);
    if (is_integer)
    {
      LUCI_INTERPRETER_CHECK(input_gate_bias()->element_type() == loco::DataType::S32);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(input_gate_bias()->element_type() == loco::DataType::FLOAT32);
    }
  }

  const Shape &forget_gate_bias_shape = forget_gate_bias()->shape();
  LUCI_INTERPRETER_CHECK(forget_gate_bias_shape.num_dims() == 1);
  LUCI_INTERPRETER_CHECK(forget_gate_bias_shape.dim(0) == n_cell);
  if (is_integer)
  {
    LUCI_INTERPRETER_CHECK(forget_gate_bias()->element_type() == loco::DataType::S32);
  }
  else
  {
    LUCI_INTERPRETER_CHECK(forget_gate_bias()->element_type() == loco::DataType::FLOAT32);
  }

  const Shape &cell_gate_bias_shape = cell_gate_bias()->shape();
  LUCI_INTERPRETER_CHECK(cell_gate_bias_shape.num_dims() == 1);
  LUCI_INTERPRETER_CHECK(cell_gate_bias_shape.dim(0) == n_cell);
  if (is_integer)
  {
    LUCI_INTERPRETER_CHECK(cell_gate_bias()->element_type() == loco::DataType::S32);
  }
  else
  {
    LUCI_INTERPRETER_CHECK(cell_gate_bias()->element_type() == loco::DataType::FLOAT32);
  }

  const Shape &output_gate_bias_shape = output_gate_bias()->shape();
  LUCI_INTERPRETER_CHECK(output_gate_bias_shape.num_dims() == 1);
  LUCI_INTERPRETER_CHECK(output_gate_bias_shape.dim(0) == n_cell);
  if (is_integer)
  {
    LUCI_INTERPRETER_CHECK(output_gate_bias()->element_type() == loco::DataType::S32);
  }
  else
  {
    LUCI_INTERPRETER_CHECK(output_gate_bias()->element_type() == loco::DataType::FLOAT32);
  }

  if (projection_weights() != nullptr)
  {
    const Shape &projection_weights_shape = projection_weights()->shape();
    LUCI_INTERPRETER_CHECK(projection_weights_shape.num_dims() == 2);
    LUCI_INTERPRETER_CHECK(projection_weights_shape.dim(0) == n_output);
    LUCI_INTERPRETER_CHECK(projection_weights_shape.dim(1) == n_cell);
  }

  if (projection_bias() != nullptr)
  {
    const Shape &projection_bias_shape = projection_bias()->shape();
    LUCI_INTERPRETER_CHECK(projection_bias_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(projection_bias_shape.dim(0) == n_output);
    if (is_integer)
    {
      LUCI_INTERPRETER_CHECK(projection_bias()->element_type() == loco::DataType::S32);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(projection_bias()->element_type() == loco::DataType::FLOAT32);
    }
  }

  // Making sure the projection tensors are consistent:
  // 1) If projection weight is not present, then projection bias should not be
  // present.
  // 2) If projection weight is present, then projection bias is optional.
  // TODO(ghodrat): make sure this is correct.
  const bool projecton_tensors_consistent =
    ((projection_weights() != nullptr) || (projection_bias() == nullptr));
  LUCI_INTERPRETER_CHECK(projecton_tensors_consistent == true);

  if (use_layer_norm)
  {
    if (use_cifg)
    {
      LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients() == nullptr);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients() != nullptr)

      const Shape &input_layer_norm_coefficients_shape = input_layer_norm_coefficients()->shape();
      LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients_shape.num_dims() == 1);
      LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients_shape.dim(0) == n_cell);
      if (is_integer)
      {
        LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients()->element_type() ==
                               loco::DataType::S16);
      }
      else
      {
        LUCI_INTERPRETER_CHECK(input_layer_norm_coefficients()->element_type() ==
                               loco::DataType::FLOAT32);
      }
    }

    const Shape &forget_layer_norm_coefficients_shape = forget_layer_norm_coefficients()->shape();
    LUCI_INTERPRETER_CHECK(forget_layer_norm_coefficients_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(forget_layer_norm_coefficients_shape.dim(0) == n_cell);
    if (is_integer)
    {
      LUCI_INTERPRETER_CHECK(forget_layer_norm_coefficients()->element_type() ==
                             loco::DataType::S16);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(forget_layer_norm_coefficients()->element_type() ==
                             loco::DataType::FLOAT32);
    }

    const Shape &cell_layer_norm_coefficients_shape = cell_layer_norm_coefficients()->shape();
    LUCI_INTERPRETER_CHECK(cell_layer_norm_coefficients_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(cell_layer_norm_coefficients_shape.dim(0) == n_cell);
    if (is_integer)
    {
      LUCI_INTERPRETER_CHECK(cell_layer_norm_coefficients()->element_type() == loco::DataType::S16);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(cell_layer_norm_coefficients()->element_type() ==
                             loco::DataType::FLOAT32);
    }

    const Shape &output_layer_norm_coefficients_shape = output_layer_norm_coefficients()->shape();
    LUCI_INTERPRETER_CHECK(output_layer_norm_coefficients_shape.num_dims() == 1);
    LUCI_INTERPRETER_CHECK(output_layer_norm_coefficients_shape.dim(0) == n_cell);
    if (is_integer)
    {
      LUCI_INTERPRETER_CHECK(output_layer_norm_coefficients()->element_type() ==
                             loco::DataType::S16);
    }
    else
    {
      LUCI_INTERPRETER_CHECK(output_layer_norm_coefficients()->element_type() ==
                             loco::DataType::FLOAT32);
    }
  }
}

void UnidirectionalSequenceLSTM::configure()
{
  LUCI_INTERPRETER_CHECK(getInputTensors().size() == 24);
  LUCI_INTERPRETER_CHECK(getOutputTensors().size() >= 1);

  // TODO support U8
  LUCI_INTERPRETER_CHECK(input()->element_type() == loco::DataType::FLOAT32);
  const bool is_integer = false;
  const bool use_layer_norm = (forget_layer_norm_coefficients() != nullptr);

  // Inferring batch size, number of outputs and sequence length and
  // number of cells from the input tensors.
  const Shape &input_shape = input()->shape();
  LUCI_INTERPRETER_CHECK(input_shape.num_dims() > 1);
  const bool time_major = params().time_major;
  const int n_batch = time_major ? input_shape.dim(1) : input_shape.dim(0);
  // NOTE as dim(2) is accessed, we need to check this is valid
  LUCI_INTERPRETER_CHECK(input_shape.num_dims() > 2);
  const int n_input = input_shape.dim(2);

  const Shape &input_to_output_weights_shape = input_to_output_weights()->shape();
  const int n_cell = input_to_output_weights_shape.dim(0);
  LUCI_INTERPRETER_CHECK(input_to_output_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(input_to_output_weights_shape.dim(1) == n_input);

  const Shape &recurrent_to_output_weights_shape = recurrent_to_output_weights()->shape();
  LUCI_INTERPRETER_CHECK(recurrent_to_output_weights_shape.num_dims() == 2);
  LUCI_INTERPRETER_CHECK(recurrent_to_output_weights_shape.dim(0) == n_cell);

  const int n_output = recurrent_to_output_weights_shape.dim(1);

  // Check that input tensor dimensions matches with each other.
  check_input_tensor_dimensions(n_input, n_output, n_cell, use_layer_norm, is_integer);

  // Check the shape of input state tensors.
  // These tensor may be 1D or 2D. It's fine as long as the total size is
  // correct.
  const Shape &output_state_shape = output_state()->shape();
  const Shape &cell_state_shape = cell_state()->shape();
  LUCI_INTERPRETER_CHECK(output_state_shape.num_elements() == n_batch * n_output);
  LUCI_INTERPRETER_CHECK(cell_state_shape.num_elements() == n_batch * n_cell);

  // Resize the output tensors.
  Shape output_shape = Shape(input_shape.num_dims());
  for (int i = 0; i < input_shape.num_dims() - 1; i++)
  {
    output_shape.dim(i) = input_shape.dim(i);
  }
  output_shape.dim(input_shape.num_dims() - 1) = n_output;
  output()->resize(output_shape);

  // TODO import integer

  // output_state and cell_state are variable tensor; use scratchpad.
  getOutputTensors()[1]->resize(output_state_shape);
  getOutputTensors()[2]->resize(cell_state_shape);

  const bool use_cifg = (input_to_input_weights() == nullptr);
  if (use_cifg)
    getOutputTensors()[3]->resize({n_batch, n_cell * 3});
  else
    getOutputTensors()[3]->resize({n_batch, n_cell * 4});

  // hybrid not supported
  if (input_to_output_weights()->element_type() == loco::DataType::U8 &&
      input()->element_type() == loco::DataType::FLOAT32)
  {
    throw std::runtime_error("Hybrid type is not currently supported");
  }
  // TODO support hybrid
  // TODO support U8
}

void UnidirectionalSequenceLSTM::execute() const
{
  switch (input()->element_type())
  {
    case loco::DataType::FLOAT32:
      evalFloat();
      break;
    default:
      throw std::runtime_error("Unsupported type");
  }
}

void UnidirectionalSequenceLSTM::evalFloat() const
{
  const bool time_major = params().time_major;
  const bool use_layer_norm = (forget_layer_norm_coefficients() != nullptr);

  const Tensor *t_input_layer_norm_coefficients =
    use_layer_norm ? input_layer_norm_coefficients() : nullptr;
  const Tensor *t_forget_layer_norm_coefficients =
    use_layer_norm ? forget_layer_norm_coefficients() : nullptr;
  const Tensor *t_cell_layer_norm_coefficients =
    use_layer_norm ? cell_layer_norm_coefficients() : nullptr;
  const Tensor *t_output_layer_norm_coefficients =
    use_layer_norm ? output_layer_norm_coefficients() : nullptr;

  Tensor *sp_output_state = getOutputTensors()[1];
  Tensor *sp_cell_state = getOutputTensors()[2];
  Tensor *sp_scratch_buffer = getOutputTensors()[3];

  // Note: it is expected that output_state input variable tensor reset to zero,
  // also expected that this variable tensor doesn't have buffer
  auto scratchpad_data = getTensorData<float>(sp_output_state);
  std::fill_n(scratchpad_data, sp_output_state->shape().num_elements(), 0);
  scratchpad_data = getTensorData<float>(sp_cell_state);
  std::fill_n(scratchpad_data, sp_cell_state->shape().num_elements(), 0);
  scratchpad_data = getTensorData<float>(sp_scratch_buffer);
  std::fill_n(scratchpad_data, sp_scratch_buffer->shape().num_elements(), 0);

  TfLiteLSTMParams lstm_params{};
  lstm_params.activation = getTfLiteActivation(params().activation);
  lstm_params.cell_clip = params().cell_clip;
  lstm_params.proj_clip = params().proj_clip;
  lstm_params.asymmetric_quantize_inputs = params().asymmetric_quantize_inputs;

  lstm::EvalFloat(input(), input_to_input_weights(), input_to_forget_weights(),
                  input_to_cell_weights(), input_to_output_weights(),

                  recurrent_to_input_weights(), recurrent_to_forget_weights(),
                  recurrent_to_cell_weights(), recurrent_to_output_weights(),

                  cell_to_input_weights(), cell_to_forget_weights(), cell_to_output_weights(),

                  t_input_layer_norm_coefficients, t_forget_layer_norm_coefficients,
                  t_cell_layer_norm_coefficients, t_output_layer_norm_coefficients,
                  /*aux_input=*/nullptr,
                  /*aux_input_to_input_weights=*/nullptr,
                  /*aux_input_to_forget_weights=*/nullptr,
                  /*aux_input_to_cell_weights=*/nullptr,
                  /*aux_input_to_output_weights=*/nullptr, input_gate_bias(), forget_gate_bias(),
                  cell_gate_bias(), output_gate_bias(),

                  projection_weights(), projection_bias(), &lstm_params,
                  /*forward_sequence=*/true, time_major,
                  /*output_offset=*/0, sp_scratch_buffer, sp_output_state, sp_cell_state, output());
}

} // namespace kernels
} // namespace luci_interpreter