Update MultiComponentStateModeCalculator.cxx; sqrt is not constexpr
sqrt is not constexpr by default, although gcc accepts it, clang chokes. The cmath constants M_2_SQRTPI and M_SQRT2 can be used, though.
sqrt is not constexpr by default, although gcc accepts it, clang chokes. The cmath constants M_2_SQRTPI and M_SQRT2 can be used, though.