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## Class template static_rational

boost::units::static_rational — Compile time rational number.

## Synopsis

    // In header: <boost/units/static_rational.hpp>

    template<integer_type N, integer_type D = 1>
    class static_rational {
    public:
      // types
      typedef unspecified                               tag;
      typedef static_rational< Numerator, Denominator > type;  // static_rational<N,D> reduced by GCD

      // construct/copy/destruct
      static_rational();

      // public static functions
      static integer_type numerator() ;
      static integer_type denominator() ;
      static const integer_type Numerator;
      static const integer_type Denominator;
    };

## Description

This is an implementation of a compile time rational number, where `static_rational<N,D>` represents a rational number with numerator `N` and denominator `D`. Because of the potential for ambiguity arising from multiple equivalent values of `static_rational` (e.g. `static_rational<6,2>==static_rational<3>`), static rationals should always be accessed through `static_rational<N,D>::type`. Template specialization prevents instantiation of zero denominators (i.e. `static_rational<N,0>`). The following compile-time arithmetic operators are provided for static_rational variables only (no operators are defined between long and static_rational):

- `mpl::negate`

- `mpl::plus`

- `mpl::minus`

- `mpl::times`

- `mpl::divides`

Neither `static_power` nor `static_root` are defined for `static_rational`. This is because template types may not be floating point values, while powers and roots of rational numbers can produce floating point values.

### `static_rational` public construct/copy/destruct

1.     static_rational();

### `static_rational` public static functions

1.     static integer_type numerator() ;

2.     static integer_type denominator() ;