half Class Reference

half Class Reference#

half: half_float::half Class Reference

Half-precision floating point type. More...

#include <half.hpp>

Public Member Functions

constexpr half () noexcept
 Default constructor. More...
 
 half (detail::expr rhs)
 Copy constructor. More...
 
 half (float rhs)
 Conversion constructor. More...
 
 operator float () const
 Conversion to single-precision. More...
 
halfoperator= (detail::expr rhs)
 Assignment operator. More...
 
template<typename T >
detail::enable< half &, T >::type operator+= (T rhs)
 Arithmetic assignment. More...
 
template<typename T >
detail::enable< half &, T >::type operator-= (T rhs)
 Arithmetic assignment. More...
 
template<typename T >
detail::enable< half &, T >::type operator*= (T rhs)
 Arithmetic assignment. More...
 
template<typename T >
detail::enable< half &, T >::type operator/= (T rhs)
 Arithmetic assignment. More...
 
halfoperator= (float rhs)
 Assignment operator. More...
 
halfoperator+= (float rhs)
 Arithmetic assignment. More...
 
halfoperator-= (float rhs)
 Arithmetic assignment. More...
 
halfoperator*= (float rhs)
 Arithmetic assignment. More...
 
halfoperator/= (float rhs)
 Arithmetic assignment. More...
 
halfoperator++ ()
 Prefix increment. More...
 
halfoperator-- ()
 Prefix decrement. More...
 
half operator++ (int)
 Postfix increment. More...
 
half operator-- (int)
 Postfix decrement. More...
 

Private Member Functions

constexpr half (detail::binary_t, detail::uint16 bits) noexcept
 Constructor. More...
 

Private Attributes

detail::uint16 data_
 Internal binary representation.
 

Static Private Attributes

static const std::float_round_style round_style = (std::float_round_style)( -1 )
 Rounding mode to use.
 

Friends

struct detail::functions
 
struct detail::unary_specialized< half >
 
struct detail::binary_specialized< half, half >
 
template<typename , typename , std::float_round_style >
struct detail::half_caster
 
class std::numeric_limits< half >
 
struct std::hash< half >
 
half literal::operator""_h (long double)
 

Detailed Description

Half-precision floating point type.

This class implements an IEEE-conformant half-precision floating point type with the usual arithmetic operators and conversions. It is implicitly convertible to single-precision floating point, which makes artihmetic expressions and functions with mixed-type operands to be of the most precise operand type. Additionally all arithmetic operations (and many mathematical functions) are carried out in single-precision internally. All conversions from single- to half-precision are done using the library's default rounding mode, but temporary results inside chained arithmetic expressions are kept in single-precision as long as possible (while of course still maintaining a strong half-precision type).

According to the C++98/03 definition, the half type is not a POD type. But according to C++11's less strict and extended definitions it is both a standard layout type and a trivially copyable type (even if not a POD type), which means it can be standard-conformantly copied using raw binary copies. But in this context some more words about the actual size of the type. Although the half is representing an IEEE 16-bit type, it does not neccessarily have to be of exactly 16-bits size. But on any reasonable implementation the actual binary representation of this type will most probably not ivolve any additional "magic" or padding beyond the simple binary representation of the underlying 16-bit IEEE number, even if not strictly guaranteed by the standard. But even then it only has an actual size of 16 bits if your C++ implementation supports an unsigned integer type of exactly 16 bits width. But this should be the case on nearly any reasonable platform.

So if your C++ implementation is not totally exotic or imposes special alignment requirements, it is a reasonable assumption that the data of a half is just comprised of the 2 bytes of the underlying IEEE representation.

Definition at line 1075 of file half.hpp.

Constructor & Destructor Documentation

◆ half() [1/4]

constexpr half_float::half::half ( )
inlineconstexprnoexcept

Default constructor.

This initializes the half to 0. Although this does not match the builtin types' default-initialization semantics and may be less efficient than no initialization, it is needed to provide proper value-initialization semantics.

Definition at line 1093 of file half.hpp.

◆ half() [2/4]

half_float::half::half ( detail::expr  rhs)
inline

Copy constructor.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to copy from

Definition at line 1098 of file half.hpp.

◆ half() [3/4]

half_float::half::half ( float  rhs)
inlineexplicit

Conversion constructor.

Parameters
rhsfloat to convert

Definition at line 1102 of file half.hpp.

◆ half() [4/4]

constexpr half_float::half::half ( detail::binary_t  ,
detail::uint16  bits 
)
inlineconstexprprivatenoexcept

Constructor.

Parameters
bitsbinary representation to set half to

Definition at line 1185 of file half.hpp.

Member Function Documentation

◆ operator float()

half_float::half::operator float ( ) const
inline

Conversion to single-precision.

Returns
single precision value representing expression value

Definition at line 1106 of file half.hpp.

◆ operator=() [1/2]

half& half_float::half::operator= ( detail::expr  rhs)
inline

Assignment operator.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to copy from
Returns
reference to this half

Definition at line 1112 of file half.hpp.

◆ operator+=() [1/2]

template<typename T >
detail::enable<half&,T>::type half_float::half::operator+= ( rhs)
inline

Arithmetic assignment.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to add
Returns
reference to this half

Definition at line 1118 of file half.hpp.

◆ operator-=() [1/2]

template<typename T >
detail::enable<half&,T>::type half_float::half::operator-= ( rhs)
inline

Arithmetic assignment.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to subtract
Returns
reference to this half

Definition at line 1124 of file half.hpp.

◆ operator*=() [1/2]

template<typename T >
detail::enable<half&,T>::type half_float::half::operator*= ( rhs)
inline

Arithmetic assignment.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to multiply with
Returns
reference to this half

Definition at line 1130 of file half.hpp.

◆ operator/=() [1/2]

template<typename T >
detail::enable<half&,T>::type half_float::half::operator/= ( rhs)
inline

Arithmetic assignment.

Template Parameters
Ttype of concrete half expression
Parameters
rhshalf expression to divide by
Returns
reference to this half

Definition at line 1136 of file half.hpp.

◆ operator=() [2/2]

half& half_float::half::operator= ( float  rhs)
inline

Assignment operator.

Parameters
rhssingle-precision value to copy from
Returns
reference to this half

Definition at line 1141 of file half.hpp.

◆ operator+=() [2/2]

half& half_float::half::operator+= ( float  rhs)
inline

Arithmetic assignment.

Parameters
rhssingle-precision value to add
Returns
reference to this half

Definition at line 1146 of file half.hpp.

◆ operator-=() [2/2]

half& half_float::half::operator-= ( float  rhs)
inline

Arithmetic assignment.

Parameters
rhssingle-precision value to subtract
Returns
reference to this half

Definition at line 1151 of file half.hpp.

◆ operator*=() [2/2]

half& half_float::half::operator*= ( float  rhs)
inline

Arithmetic assignment.

Parameters
rhssingle-precision value to multiply with
Returns
reference to this half

Definition at line 1156 of file half.hpp.

◆ operator/=() [2/2]

half& half_float::half::operator/= ( float  rhs)
inline

Arithmetic assignment.

Parameters
rhssingle-precision value to divide by
Returns
reference to this half

Definition at line 1161 of file half.hpp.

◆ operator++() [1/2]

half& half_float::half::operator++ ( )
inline

Prefix increment.

Returns
incremented half value

Definition at line 1165 of file half.hpp.

◆ operator--() [1/2]

half& half_float::half::operator-- ( )
inline

Prefix decrement.

Returns
decremented half value

Definition at line 1169 of file half.hpp.

◆ operator++() [2/2]

half half_float::half::operator++ ( int  )
inline

Postfix increment.

Returns
non-incremented half value

Definition at line 1173 of file half.hpp.

◆ operator--() [2/2]

half half_float::half::operator-- ( int  )
inline

Postfix decrement.

Returns
non-decremented half value

Definition at line 1177 of file half.hpp.


The documentation for this class was generated from the following file:
  • /home/docs/checkouts/readthedocs.org/user_builds/advanced-micro-devices-half/checkouts/latest/include/half.hpp