Computes the midpoint of two points
<mp-units/math.h>
template<
    auto R1,
    auto Origin,
    typename Rep1,
    auto R2,
    typename Rep2>
requires requires(Rep1 a, Rep2 b) {
    get_common_reference(R1, R2);
    requires requires { midpoint(a, b); } || requires { std::midpoint(a, b); };
  }
[[nodiscard]]
constexpr
QuantityPointOf<get_quantity_spec(get_common_reference(R1, R2))> auto
midpoint(
    quantity_point<R1, Origin, Rep1> const& a,
    quantity_point<R2, Origin, Rep2> const& b) noexcept;
| Name | Description | 
|---|---|
| a | A quantity point | 
| b | A quantity point |