提供 16 位浮点支持。 更多...
| 头： | #include <QFloat16> |
| CMake: |
find_package(Qt6 COMPONENTS Core REQUIRED)
target_link_libraries(mytarget PRIVATE Qt6::Core) |
| qmake: | QT += core |
| Since: | Qt 5.9 |
| qfloat16 (Qt::Initialization) | |
| qfloat16 | copySign (qfloat16 sign ) const |
| bool | isNormal () const |
| 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 ) |
| bool | qIsFinite (qfloat16 f ) |
| bool | qIsInf (qfloat16 f ) |
| bool | qIsNaN (qfloat16 f ) |
| qint64 | qRound64 (qfloat16 value ) |
| int | qRound (qfloat16 value ) |
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.
[since 6.1]
qfloat16::
qfloat16
(
Qt::Initialization
)
Constructs a qfloat16 without initializing the value.
该函数在 Qt 6.1 引入。
[since 5.15]
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().
该函数在 Qt 5.15 引入。
[since 5.14]
bool
qfloat16::
isNormal
() const
返回
true
若此
qfloat16
值是有限的且采用正常形式。
该函数在 Qt 5.14 引入。
另请参阅 qFpClassify ().
[since 5.11]
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.
该函数在 Qt 5.11 引入。
[since 5.11]
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.
该函数在 Qt 5.11 引入。
[since 5.14]
int
qFpClassify
(
qfloat16
val
)
此函数重载 qFpClassify (float).
Returns the floating-point class of val .
该函数在 Qt 5.14 引入。
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.
This function overloads qIsFinite(float).
返回 true 若
qfloat16
f
是有限数。
This function overloads qIsInf(float).
返回 true 若
qfloat16
f
相当于无穷大。
This function overloads qIsNaN(float).
返回 true 若
qfloat16
f
是 NaN (非数字)。
此函数重载 qRound64 (float).
圆整 value 到最近 64 位整数。
此函数重载 qRound (float).
圆整 value 到最近整数。