qfloat16 类

提供 16 位浮点支持。 更多...

头：	#include <QFloat16>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake:	QT += core

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此类 partially comparable .

此类 partially comparable with float, double , long double, qint8 , quint8 , qint16 , quint16 , qint32 , quint32 , long, unsigned long, qint64 ，和 quint64 .

此类 partially comparable with qint128 and quint128 .

Comparison with 128-bit integral types is only supported if Qt provides these types.

公共函数

(since 6.1)	qfloat16 (Qt::Initialization)
qfloat16	copySign (qfloat16 sign ) const
bool	isNormal () const

相关非成员

void	qFloatFromFloat16 (float * out , const qfloat16 * in , qsizetype len )
void	qFloatToFloat16 (qfloat16 * out , const float * in , qsizetype len )
int	qFpClassify (qfloat16 val )
bool	qFuzzyCompare (qfloat16 p1 , qfloat16 p2 )
(since 6.5.3) size_t	qHash (qfloat16 key , size_t seed = 0)
bool	qIsFinite (qfloat16 f )
bool	qIsInf (qfloat16 f )
bool	qIsNaN (qfloat16 f )
qint64	qRound64 (qfloat16 value )
int	qRound (qfloat16 value )
QDataStream &	operator<< (QDataStream & ds , qfloat16 f )
QDataStream &	operator>> (QDataStream & ds , qfloat16 & f )

详细描述

The qfloat16 class provides support for half-precision (16-bit) floating point data. It is fully compliant with IEEE 754 as a storage type. This implies that any arithmetic operation on a qfloat16 instance results in the value first being converted to a float . This conversion to and from float is performed by hardware when possible, but on processors that do not natively support half-precision, the conversion is performed through a sequence of lookup table operations.

qfloat16 should be treated as if it were a POD (plain old data) type. Consequently, none of the supported operations need any elaboration beyond stating that it supports all arithmetic operators incident to floating point types.

注意： On x86 and x86-64 that to get hardware accelerated conversions you must compile with F16C or AVX2 enabled, or use qFloatToFloat16 () 和 qFloatFromFloat16 () which will detect F16C at runtime.

成员函数文档编制

[explicit noexcept, since 6.1] qfloat16:: qfloat16 ( Qt::Initialization )

Constructs a qfloat16 without initializing the value.

该函数在 Qt 6.1 引入。

[noexcept] qfloat16 qfloat16:: copySign ( qfloat16 sign ) const

Returns a qfloat16 with the sign of sign but the rest of its value taken from this qfloat16. Serves as qfloat16's equivalent of std::copysign().

[constexpr noexcept] bool qfloat16:: isNormal () const

返回 true 若此 qfloat16 值是有限的且采用正常形式。

另请参阅 qFpClassify ().

相关非成员

[noexcept] void qFloatFromFloat16 ( float * out , const qfloat16 * in , qsizetype len )

转换 len qfloat16 from in to floats and stores them in out . Both in and out must have len allocated entries.

This function is faster than converting values one by one, and will do runtime F16C detection on x86 and x86-64 hardware.

[noexcept] void qFloatToFloat16 ( qfloat16 * out , const float * in , qsizetype len )

转换 len floats from in to qfloat16 and stores them in out . Both in and out must have len allocated entries.

This function is faster than converting values one by one, and will do runtime F16C detection on x86 and x86-64 hardware.

[noexcept] int qFpClassify ( qfloat16 val )

此函数重载 qFpClassify (float).

Returns the floating-point class of val .

[noexcept] bool qFuzzyCompare ( qfloat16 p1 , qfloat16 p2 )

此函数重载 qFuzzyCompare (float, float).

比较浮点值 p1 and p2 并返回 true 若它们被认为相等，否则 false .

The two numbers are compared in a relative way, where the exactness is stronger the smaller the numbers are.

[noexcept, since 6.5.3] size_t qHash ( qfloat16 key , size_t seed = 0)

返回哈希值为 key ，使用 seed 做计算种子。

注意： In Qt versions before 6.5, this operation was provided by the qHash(float) overload. In Qt versions 6.5.0 to 6.5.2, this functionality was broken in various ways. In Qt versions 6.5.3 and 6.6 onwards, this overload restores the Qt 6.4 behavior.

This function was introduced in Qt 6.5.3.

[noexcept] bool qIsFinite ( qfloat16 f )

此函数重载 qIsFinite (float).

返回 true 若 qfloat16 f 是有限数。

[noexcept] bool qIsInf ( qfloat16 f )

此函数重载 qIsInf (float).

返回 true 若 qfloat16 f 相当于无穷大。

[noexcept] bool qIsNaN ( qfloat16 f )

此函数重载 qIsNaN (float).

返回 true 若 qfloat16 f 是 NaN (非数字)。

[noexcept] qint64 qRound64 ( qfloat16 value )

此函数重载 qRound64 (float).

圆整 value 到最近 64 位整数。

[noexcept] int qRound ( qfloat16 value )

此函数重载 qRound (float).

圆整 value 到最近整数。

QDataStream & operator<< ( QDataStream & ds , qfloat16 f )

Writes a floating point number, f , to the stream ds using the standard IEEE 754 format. Returns a reference to the stream.

注意： In Qt versions prior to 6.3, this was a member function on QDataStream .

QDataStream & operator>> ( QDataStream & ds , qfloat16 & f )

Reads a floating point number from the stream ds into f , using the standard IEEE 754 format. Returns a reference to the stream.

注意： In Qt versions prior to 6.3, this was a member function on QDataStream .