Method FixedInt

include/Eigen/Eigen/src/Core/util/IntegralConstant.h:57–58

  EIGEN_CONSTEXPR operator int() const { return value; }
  
  EIGEN_CONSTEXPR
  FixedInt() = default;
  
  EIGEN_CONSTEXPR
  FixedInt(std::integral_constant<int,N>) {}