use_keys_cubic Class — pytorch Architecture

Source Code

aten/src/ATen/native/cpu/UpSampleKernel.cpp lines 1334–1350

  template<typename scalar_t, bool use_keys_cubic=true>
  static inline scalar_t aa_filter(scalar_t x) {
    // https://en.wikipedia.org/wiki/Bicubic_interpolation#Bicubic_convolution_algorithm
    // a = -0.5 was proposed by R. Keys in "Cubic convolution interpolation for digital image processing"
    // We are using -0.5 for bicubic, antialiasing=true (compatibility with PIL)
    // and using -0.75 for bicubic, antialiasing=false (compatibility with Opencv)
    constexpr scalar_t a = use_keys_cubic ? -0.5 : -0.75;

    x = std::abs(x);
    if (x < 1.0) {
        return cubic_convolution1(x, a);
    }
    if (x < 2.0) {
        return cubic_convolution2(x, a);
    }
    return 0.0;
  }