  void Compute(OpKernelContext* ctx) override {
    const Tensor& input = ctx->input(kInputTensorIndex);
    const Tensor& input_min = ctx->input(kInputMinIndex);
    const Tensor& input_max = ctx->input(kInputMaxIndex);

    const size_t depth = input_max.NumElements();
    OP_REQUIRES(
        ctx, input_min.dim_size(0) == depth,
        errors::InvalidArgument("input_min has incorrect size, expected ",
                                depth, " was ", input_min.dim_size(0)));
    OP_REQUIRES(
        ctx, input_max.dim_size(0) == depth,
        errors::InvalidArgument("input_max has incorrect size, expected ",
                                depth, " was ", input_max.dim_size(0)));
    OP_REQUIRES(
        ctx, input_min.NumElements() == depth,
        errors::InvalidArgument("input_min must have the same number of "
                                "elements as input_max, got ",
                                input_min.NumElements(), " and ", depth));
    OP_REQUIRES(ctx, input.NumElements() > 0,
                errors::InvalidArgument("input must not be empty"));
    OP_REQUIRES(ctx, input.dims() == 4,
                errors::InvalidArgument("input must be in NHWC format"));
    OP_REQUIRES(
        ctx, input.dim_size(3) == depth,
        errors::InvalidArgument(
            "input must have same number of channels as length of input_min: ",
            input.dim_size(3), " vs ", depth));

    const float* input_min_data = input_min.flat<float>().data();
    const float* input_max_data = input_max.flat<float>().data();
    std::vector<float> ranges(depth);
    bool is_non_negative = true;
    Eigen::array<int, 2> shuffling({1, 0});
    auto input_matrix = input.flat_inner_dims<qint32>();

    // TODO: verify performance of not transposing and finding the min max
    // directly from input_matrix vs the one presented below of transposing and
    // using the transposed matrix as the transposing operation in itself might
    // be more costly.
    // Note that this operation is a calibration step for quantization and will
    // cease to exist in the final inference graph(will exist as a const node).
    auto transposed_input = input_matrix.shuffle(shuffling);

    // Find the ranges of each channel in parallel.
    float out_min_max = std::numeric_limits<float>::min();

#ifdef ENABLE_ONEDNN_OPENMP
#ifdef _MSC_VER
#pragma omp parallel for
#else
#pragma omp parallel for reduction(max : out_min_max)
#endif
#endif  // ENABLE_ONEDNN_OPENMP
    // TODO: Add eigen parallel_for
    for (int64_t i = 0; i < depth; ++i) {
      Eigen::Tensor<qint32, 0, Eigen::RowMajor> min =
          transposed_input.chip<0>(i).minimum();
      Eigen::Tensor<qint32, 0, Eigen::RowMajor> max =
          transposed_input.chip<0>(i).maximum();
      const int32_t min_per_channel = min();
      const int32_t max_per_channel = max();
      const int32_t abs_max =
          std::max(std::abs(min_per_channel), std::abs(max_per_channel));
      float scale =
          std::max(std::abs(input_min_data[i]), std::abs(input_max_data[i]));
      ranges[i] =
          scale * static_cast<float>(abs_max) / static_cast<float>(1L << 31);
      if (min_per_channel < 0) is_non_negative = false;

      // Thread-local out_min_max.
      out_min_max = std::max(out_min_max, ranges[i]);
    }

    // All local out_min_max gets max-reduced into one global out_min_max at
    // the end of the loop by specifying reduction(max:out_min_max) along with
    // omp parallel for.

    // Fixing max to clip_value_max_ (example 6.0 to support relu6)
    if (out_min_max > clip_value_max_) out_min_max = clip_value_max_;

    Tensor* output_min = nullptr;
    Tensor* output_max = nullptr;
    OP_REQUIRES_OK(ctx, ctx->allocate_output(kOutputMinIndex, {}, &output_min));
    OP_REQUIRES_OK(ctx, ctx->allocate_output(kOutputMaxIndex, {}, &output_max));
    output_min->flat<float>()(0) = is_non_negative ? 0.0f : -out_min_max;
    output_max->flat<float>()(0) = out_min_max;
  }
  void Compute(OpKernelContext* ctx) override {
    const Tensor& input = ctx->input(kInputTensorIndex);
    const Tensor& input_min = ctx->input(kInputMinIndex);
    const Tensor& input_max = ctx->input(kInputMaxIndex);

    const size_t depth = input_max.NumElements();
    OP_REQUIRES(
        ctx, input_min.dim_size(0) == depth,
        errors::InvalidArgument("input_min has incorrect size, expected ",
                                depth, " was ", input_min.dim_size(0)));
    OP_REQUIRES(
        ctx, input_max.dim_size(0) == depth,
        errors::InvalidArgument("input_max has incorrect size, expected ",
                                depth, " was ", input_max.dim_size(0)));
    OP_REQUIRES(
        ctx, input_min.NumElements() == depth,
        errors::InvalidArgument("input_min must have the same number of "
                                "elements as input_max, got ",
                                input_min.NumElements(), " and ", depth));
    OP_REQUIRES(ctx, input.NumElements() > 0,
                errors::InvalidArgument("input must not be empty"));
    OP_REQUIRES(ctx, input.dims() == 4,
                errors::InvalidArgument("input must be in NHWC format"));
    OP_REQUIRES(
        ctx, input.dim_size(3) == depth,
        errors::InvalidArgument(
            "input must have same number of channels as length of input_min: ",
            input.dim_size(3), " vs ", depth));

    const float* input_min_data = input_min.flat<float>().data();
    const float* input_max_data = input_max.flat<float>().data();
    std::vector<float> ranges(depth);
    bool is_non_negative = true;
    Eigen::array<int, 2> shuffling({1, 0});
    auto input_matrix = input.flat_inner_dims<qint32>();

     
     
     
     
     
     
    auto transposed_input = input_matrix.shuffle(shuffling);

     
    float out_min_max = std::numeric_limits<float>::min();

#ifdef ENABLE_ONEDNN_OPENMP
#ifdef _MSC_VER
#pragma omp parallel for
#else
#pragma omp parallel for reduction(max : out_min_max)
#endif
#endif   
     
    for (int64_t i = 0; i < depth; ++i) {
      Eigen::Tensor<qint32, 0, Eigen::RowMajor> min =
          transposed_input.chip<0>(i).minimum();
      Eigen::Tensor<qint32, 0, Eigen::RowMajor> max =
          transposed_input.chip<0>(i).maximum();
      const int32_t min_per_channel = min();
      const int32_t max_per_channel = max();
      const int32_t abs_max =
          std::max(std::abs(min_per_channel), std::abs(max_per_channel));
      float scale =
          std::max(std::abs(input_min_data[i]), std::abs(input_max_data[i]));
      ranges[i] =
          scale * static_cast<float>(abs_max) / static_cast<float>(1L << 31);
      if (min_per_channel < 0) is_non_negative = false;

       
      out_min_max = std::max(out_min_max, ranges[i]);
    }

     
     
     

     
    if (out_min_max > clip_value_max_) out_min_max = clip_value_max_;

    Tensor* output_min = nullptr;
    Tensor* output_max = nullptr;
    OP_REQUIRES_OK(ctx, ctx->allocate_output(kOutputMinIndex, {}, &output_min));
    OP_REQUIRES_OK(ctx, ctx->allocate_output(kOutputMaxIndex, {}, &output_max));
    output_min->flat<float>()(0) = is_non_negative ? 0.0f : -out_min_max;
    output_max->flat<float>()(0) = out_min_max;
  }