
[section:rounding Rounding Truncation and Integer Conversion]

[section:round Rounding Functions]

``#include <boost/math/special_functions/round.hpp>``

   template <class T>
   T round(const T& v);
   
   template <class T, class Policy>
   T round(const T& v, const Policy&);
   
   template <class T>
   int iround(const T& v);

   template <class T, class Policy>
   int iround(const T& v, const Policy&);

   template <class T>
   long lround(const T& v);

   template <class T, class Policy>
   long lround(const T& v, const Policy&);

   template <class T>
   long long llround(const T& v);

   template <class T, class Policy>
   long long llround(const T& v, const Policy&);

These functions return the closest integer to the argument /v/.

Halfway cases are rounded away from zero, regardless of the current rounding
direction.

If the argument /v/ is either non-finite or else outside the range
of the result type, then returns the result of __rounding_error: by
default this throws an instance of boost::math::rounding_error.

[endsect]

[section:trunc Truncation Functions]

``#include <boost/math/special_functions/trunc.hpp>``

   template <class T>
   T trunc(const T& v);

   template <class T, class Policy>
   T trunc(const T& v, const Policy&);

   template <class T>
   int itrunc(const T& v);

   template <class T, class Policy>
   int itrunc(const T& v, const Policy&);

   template <class T>
   long ltrunc(const T& v);

   template <class T, class Policy>
   long ltrunc(const T& v, const Policy&);

   template <class T>
   long long lltrunc(const T& v);

   template <class T, class Policy>
   long long lltrunc(const T& v, const Policy&);

The trunc functions round their argument to the integer value,
nearest to but no larger in magnitude than the argument.

For example `itrunc(3.7)` would return `3` and `ltrunc(-4.6)` 
would return `-4`.

If the argument /v/ is either non-finite or else outside the range
of the result type, then returns the result of __rounding_error: by
default this throws an instance of boost::math::rounding_error.

[endsect]

[section:modf Integer and Fractional Part Splitting (modf)]

``#include <boost/math/special_functions/modf.hpp>``

   template <class T>
   T modf(const T& v, T* ipart);

   template <class T, class Policy>
   T modf(const T& v, T* ipart, const Policy&);

   template <class T>
   T modf(const T& v, int* ipart);

   template <class T, class Policy>
   T modf(const T& v, int* ipart, const Policy&);

   template <class T>
   T modf(const T& v, long* ipart);

   template <class T, class Policy>
   T modf(const T& v, long* ipart, const Policy&);

   template <class T>
   T modf(const T& v, long long* ipart);

   template <class T, class Policy>
   T modf(const T& v, long long* ipart, const Policy&);

The `modf` functions store the integer part of /v/ in `*ipart` 
and return the fractional part of /v/.

If the argument /v/ is either non-finite or else outside the range
of the result type, then returns the result of __rounding_error: by
default this throws an instance of boost::math::rounding_error.

[endsect]


[endsect] [/section:rounding Rounding Truncation and Integer Conversion]

[/ 
  Copyright 2006 John Maddock and Paul A. Bristow.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt).
]
