C++ least square line fitting

least_square_line_fitting.cc

// https://www.varsitytutors.com/hotmath/hotmath_help/topics/line-of-best-fit.html

double CalcLineSlope(const std::vector<double>& x,
                     const std::vector<double>& y) {
  const auto n = x.size();
  const auto s_x = std::accumulate(x.begin(), x.end(), 0.0);
  const auto s_y = std::accumulate(y.begin(), y.end(), 0.0);
  const auto s_xx = std::inner_product(x.begin(), x.end(), x.begin(), 0.0);
  const auto s_xy = std::inner_product(x.begin(), x.end(), y.begin(), 0.0);
  const auto slope = (n * s_xy - s_x * s_y) / (n * s_xx - s_x * s_x);
  return slop;
}