template<typename MatType, typename CubeType>
void StructuredForests<MatType, CubeType>::
ConvTriangle(CubeType &InImage, const size_t radius)
{
  Timer::Start("ConvTriangle_my");
  if (radius == 0)
  {
    //nothing to do
  }
  else if (radius <= 1)
  {
    const double p = 12.0 / radius / (radius + 2) - 2;
    arma::vec kernel = {1, p, 1};
    kernel /= (p + 2);

    this->SepFilter2D(InImage, kernel, radius);
  }
  else
  {
    const size_t len = 2 * radius + 1;
    arma::vec kernel(len);
    for( size_t i = 0; i < radius; ++i)
      kernel(i) = i + 1;

    kernel(radius) = radius + 1;

    size_t r = radius;
    for( size_t i = radius + 1; i < len; ++i)
      kernel(i) = r--;

    kernel /= std::pow(radius + 1, 2);
    this->SepFilter2D(InImage, kernel, radius);
  }
  Timer::Stop("ConvTriangle_my");
}

template<typename MatType, typename CubeType>
void StructuredForests<MatType, CubeType>::
ConvTriangle2(CubeType& InImage, const size_t radius, CubeType& Output)
{
  Timer::Start("ConvTriangle_mlpack");
  if (radius != 0)
  {
    if (radius <= 1)
    {
      const double p = 12.0 / radius / (radius + 2) - 2;
      arma::vec kernel = {1, p, 1};
      kernel /= (p + 2);
      MatType k_mat = MatType(kernel.n_elem, kernel.n_elem);
      k_mat = kernel * kernel.t();
      NaiveConvolution<FullConvolution>::Convolution(InImage, k_mat, Output);
      //this->SepFilter2D(InImage, kernel, radius);
    }
    else
    {
      const size_t len = 2 * radius + 1;
      arma::vec kernel(len);
      for( size_t i = 0; i < radius; ++i)
        kernel(i) = i + 1;
      kernel(radius) = radius + 1;
      size_t r = radius;
      for( size_t i = radius + 1; i < len; ++i)
        kernel(i) = r--;
      kernel /= std::pow(radius + 1, 2);
      MatType k_mat = MatType(kernel.n_elem, kernel.n_elem);
      k_mat = kernel * kernel.t();
      NaiveConvolution<FullConvolution>::Convolution(InImage, k_mat, Output);
      //this->SepFilter2D(InImage, kernel, radius);
    }
  }
  Timer::Stop("ConvTriangle_mlpack");

}