DepthwiseConvUInt8.h

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/*
 * Copyright (c) 2022 Samsung Electronics Co., Ltd. All Rights Reserved
 * Copyright 2019 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.
 */
 
#ifndef __NNFW_CKER_REFERENCE_DEPTHWISE_CONV_UINT8_H__
#define __NNFW_CKER_REFERENCE_DEPTHWISE_CONV_UINT8_H__
 
#include "cker/Shape.h"
#include "cker/Types.h"
#include "cker/Utils.h"
 
namespace nnfw
{
namespace cker
{
namespace reference_integer_ops
{
inline void DepthwiseConvPerChannel(const DepthwiseConvParams &params,
                                    const int32_t *output_multiplier, const int32_t *output_shift,
                                    const Shape &input_shape, const uint8_t *input_data,
                                    const Shape &filter_shape, const uint8_t *filter_data,
                                    const int32_t *filter_zeropoint,
                                    [[maybe_unused]] const Shape &bias_shape,
                                    const int32_t *bias_data, const Shape &output_shape,
                                    uint8_t *output_data)
{
  // Get parameters.
  // TODO(b/141565753): Re-introduce ScopedProfilingLabel on Micro.
  const int stride_width = params.stride_width;
  const int stride_height = params.stride_height;
  const int dilation_width_factor = params.dilation_width_factor;
  const int dilation_height_factor = params.dilation_height_factor;
  const int pad_width = params.padding_values.width;
  const int pad_height = params.padding_values.height;
  const int depth_multiplier = params.depth_multiplier;
  const int32_t input_offset = params.input_offset;
  const int32_t output_offset = params.output_offset;
  const int32_t output_activation_min = params.quantized_activation_min;
  const int32_t output_activation_max = params.quantized_activation_max;
 
  // Check dimensions of the tensors.
  assert(input_shape.DimensionsCount() == 4);
  assert(filter_shape.DimensionsCount() == 4);
  assert(output_shape.DimensionsCount() == 4);
 
  assert(output_activation_min <= output_activation_max);
  const int batches = MatchingDim(input_shape, 0, output_shape, 0);
  [[maybe_unused]] const int output_depth = MatchingDim(filter_shape, 3, output_shape, 3);
  const int input_height = input_shape.Dims(1);
  const int input_width = input_shape.Dims(2);
  const int input_depth = input_shape.Dims(3);
  const int filter_height = filter_shape.Dims(1);
  const int filter_width = filter_shape.Dims(2);
  const int output_height = output_shape.Dims(1);
  const int output_width = output_shape.Dims(2);
  assert(output_depth == input_depth * depth_multiplier);
  assert(bias_shape.FlatSize() == output_depth);
 
  for (int batch = 0; batch < batches; ++batch)
  {
    for (int out_y = 0; out_y < output_height; ++out_y)
    {
      for (int out_x = 0; out_x < output_width; ++out_x)
      {
        for (int in_channel = 0; in_channel < input_depth; ++in_channel)
        {
          for (int m = 0; m < depth_multiplier; ++m)
          {
            const int output_channel = m + in_channel * depth_multiplier;
            const int in_x_origin = (out_x * stride_width) - pad_width;
            const int in_y_origin = (out_y * stride_height) - pad_height;
            int32_t acc = 0;
            for (int filter_y = 0; filter_y < filter_height; ++filter_y)
            {
              for (int filter_x = 0; filter_x < filter_width; ++filter_x)
              {
                const int in_x = in_x_origin + dilation_width_factor * filter_x;
                const int in_y = in_y_origin + dilation_height_factor * filter_y;
                // Zero padding by omitting the areas outside the image.
                const bool is_point_inside_image =
                  (in_x >= 0) && (in_x < input_width) && (in_y >= 0) && (in_y < input_height);
                if (is_point_inside_image)
                {
                  uint8_t input_val =
                    input_data[Offset(input_shape, batch, in_y, in_x, in_channel)];
                  uint8_t filter_val =
                    filter_data[Offset(filter_shape, 0, filter_y, filter_x, output_channel)];
 
                  // { for per-channel
                  // NOTE: The following comment is copied from tflite int8 implementation
                  //       It may not be 100% true for uint8 per-channel.
                  //
                  // Accumulate with 32 bits accumulator.
                  // In the nudging process during model quantization, we force
                  // real value of 0.0 be represented by a quantized value. This
                  // guarantees that the input_offset is a int8, even though it
                  // is represented using int32_t.
                  // int32 += int8 * (int8 - int8) so the highest value we can
                  // get from each accumulation is [-127, 127] * ([-128, 127] -
                  // [-128, 127]), which is [-32512, 32512]. log2(32512)
                  // = 14.98, which means we can accumulate at least 2^16
                  // multiplications without overflow. The accumulator is
                  // applied to a filter so the accumulation logic will hold as
                  // long as the filter size (filter_y * filter_x * in_channel)
                  // does not exceed 2^16, which is the case in all the models
                  // we have seen so far.
                  // TODO(jianlijianli): Add a check to make sure the
                  // accumulator depth is smaller than 2^16.
                  const int32_t filter_offset = -filter_zeropoint[output_channel];
                  acc += (filter_val + filter_offset) * (input_val + input_offset);
                  // } for per-channel
                }
              }
            }
            if (bias_data)
            {
              acc += bias_data[output_channel];
            }
            acc = MultiplyByQuantizedMultiplier(acc, output_multiplier[output_channel],
                                                output_shift[output_channel]);
            acc += output_offset;
            acc = std::max(acc, output_activation_min);
            acc = std::min(acc, output_activation_max);
            // For q8u per-channel, int8_t -> uint8_t
            output_data[Offset(output_shape, batch, out_y, out_x, output_channel)] =
              static_cast<uint8_t>(acc);
          }
        }
      }
    }
  }
}
 
} // namespace reference_integer_ops
} // namespace cker
} // namespace nnfw
 
#endif // __NNFW_CKER_REFERENCE_DEPTHWISE_CONV_UINT8_H__