Type Traits

Defines a series of classes to obtain unit type information at compile-time. More...

Namespaces
namespace	units::traits
	namespace representing type traits which can access the properties of types provided by the units library.

Classes
struct	units::traits::is_base_unit< T >
	Trait which tests if a class is a base_unit type. More...
struct	units::traits::is_unit< T >
	Traits which tests if a class is a unit More...
struct	units::traits::is_convertible_unit< U1, U2 >
	Trait which checks whether two units can be converted to each other. More...
struct	units::traits::is_nonlinear_scale< T, Ret >
	Trait which tests that class T meets the requirements for a non-linear scale. More...
struct	units::traits::is_convertible_unit_t< U1, U2 >
	Trait which tests whether two container types derived from unit_t are convertible to each other. More...
struct	units::traits::is_unit_t< T >
	Traits which tests if a class is a unit More...
struct	units::traits::has_linear_scale< T >
	Trait which tests whether a type is inherited from a linear scale. More...
struct	units::traits::has_decibel_scale< T >
	Trait which tests whether a type is inherited from a decibel scale. More...
struct	units::traits::is_same_scale< T1, T2 >
	Trait which tests whether two types has the same non-linear scale. More...
struct	units::traits::is_unit_value_t< T, Units >
	Trait which tests whether a type is a unit_value_t representing the given unit type. More...
struct	units::traits::is_unit_value_t_category< Category, T >
	Trait which tests whether type T is a unit_value_t with a unit type in the given category. More...

Typedefs
template<typename Ratio , std::intmax_t Eps = 10000000000>
using	units::ratio_sqrt = typename units::detail::Sqrt< Ratio, std::ratio< 1, Eps > >::type
	Calculate square root of a ratio at compile-time. More...

Detailed Description

Defines a series of classes to obtain unit type information at compile-time.

Typedef Documentation

ratio_sqrt

template<typename Ratio , std::intmax_t Eps = 10000000000>

using units::ratio_sqrt = typedef typename units::detail::Sqrt<Ratio, std::ratio<1, Eps> >::type

Calculate square root of a ratio at compile-time.

Calculates a rational approximation of the square root of the ratio. The error in the calculation is bounded by 1/epsilon (Eps). E.g. for the default value of 10000000000, the maximum error will be a/10000000000, or 1e-8, or said another way, the error will be on the order of 10^-9. Since these calculations are done at compile time, it is advisable to set epsilon to the highest value that does not cause an integer overflow in the calculation. If you can't compile ratio_sqrt due to overflow errors, reducing the value of epsilon sufficiently will correct the problem.

ratio_sqrt is guaranteed to converge for all values of Ratio which do not overflow.

Note

This function provides a rational approximation, NOT an exact value.

Template Parameters

Ratio	ratio to take the square root of. This can represent any rational value, not just integers or values with integer roots.
Eps	Value of epsilon, which represents the inverse of the maximum allowable error. This value should be chosen to be as high as possible before integer overflow errors occur in the compiler.