Primitive Type f16
f16
#116909)Expand description
A 16-bit floating point type (specifically, the “binary16” type defined in IEEE 754-2008).
This type is very similar to f32
but has decreased precision because it uses half as many
bits. Please see [the documentation for f32
or Wikipedia on
half-precision values for more information.
Implementations§
source§impl f16
impl f16
sourcepub const fn is_nan(self) -> bool
🔬This is a nightly-only experimental API. (f16
#116909)
pub const fn is_nan(self) -> bool
f16
#116909)Returns true
if this value is NaN.
sourcepub fn is_sign_positive(self) -> bool
🔬This is a nightly-only experimental API. (f128
#116909)
pub fn is_sign_positive(self) -> bool
f128
#116909)Returns true
if self
has a positive sign, including +0.0
, NaNs with
positive sign bit and positive infinity. Note that IEEE 754 doesn’t assign any
meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that
the bit pattern of NaNs are conserved over arithmetic operations, the result of
is_sign_positive
on a NaN might produce an unexpected result in some cases.
See explanation of NaN as a special value for more info.
sourcepub fn is_sign_negative(self) -> bool
🔬This is a nightly-only experimental API. (f128
#116909)
pub fn is_sign_negative(self) -> bool
f128
#116909)Returns true
if self
has a negative sign, including -0.0
, NaNs with
negative sign bit and negative infinity. Note that IEEE 754 doesn’t assign any
meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that
the bit pattern of NaNs are conserved over arithmetic operations, the result of
is_sign_negative
on a NaN might produce an unexpected result in some cases.
See explanation of NaN as a special value for more info.
sourcepub fn to_bits(self) -> u16
🔬This is a nightly-only experimental API. (f16
#116909)
pub fn to_bits(self) -> u16
f16
#116909)Raw transmutation to u16
.
This is currently identical to transmute::<f16, u16>(self)
on all platforms.
See from_bits
for some discussion of the
portability of this operation (there are almost no issues).
Note that this function is distinct from as
casting, which attempts to
preserve the numeric value, and not the bitwise value.
sourcepub fn from_bits(v: u16) -> f16
🔬This is a nightly-only experimental API. (f16
#116909)
pub fn from_bits(v: u16) -> f16
f16
#116909)Raw transmutation from u16
.
This is currently identical to transmute::<u16, f16>(v)
on all platforms.
It turns out this is incredibly portable, for two reasons:
- Floats and Ints have the same endianness on all supported platforms.
- IEEE 754 very precisely specifies the bit layout of floats.
However there is one caveat: prior to the 2008 version of IEEE 754, how to interpret the NaN signaling bit wasn’t actually specified. Most platforms (notably x86 and ARM) picked the interpretation that was ultimately standardized in 2008, but some didn’t (notably MIPS). As a result, all signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
Rather than trying to preserve signaling-ness cross-platform, this implementation favors preserving the exact bits. This means that any payloads encoded in NaNs will be preserved even if the result of this method is sent over the network from an x86 machine to a MIPS one.
If the results of this method are only manipulated by the same architecture that produced them, then there is no portability concern.
If the input isn’t NaN, then there is no portability concern.
If you don’t care about signalingness (very likely), then there is no portability concern.
Note that this function is distinct from as
casting, which attempts to
preserve the numeric value, and not the bitwise value.
Trait Implementations§
1.22.0 · source§impl AddAssign<&f16> for f16
impl AddAssign<&f16> for f16
source§fn add_assign(&mut self, other: &f16)
fn add_assign(&mut self, other: &f16)
+=
operation. Read more1.8.0 · source§impl AddAssign for f16
impl AddAssign for f16
source§fn add_assign(&mut self, other: f16)
fn add_assign(&mut self, other: f16)
+=
operation. Read more1.22.0 · source§impl DivAssign<&f16> for f16
impl DivAssign<&f16> for f16
source§fn div_assign(&mut self, other: &f16)
fn div_assign(&mut self, other: &f16)
/=
operation. Read more1.8.0 · source§impl DivAssign for f16
impl DivAssign for f16
source§fn div_assign(&mut self, other: f16)
fn div_assign(&mut self, other: f16)
/=
operation. Read more1.22.0 · source§impl MulAssign<&f16> for f16
impl MulAssign<&f16> for f16
source§fn mul_assign(&mut self, other: &f16)
fn mul_assign(&mut self, other: &f16)
*=
operation. Read more1.8.0 · source§impl MulAssign for f16
impl MulAssign for f16
source§fn mul_assign(&mut self, other: f16)
fn mul_assign(&mut self, other: f16)
*=
operation. Read more1.0.0 (const: unstable) · source§impl PartialEq for f16
impl PartialEq for f16
1.0.0 · source§impl PartialOrd for f16
impl PartialOrd for f16
source§fn le(&self, other: &f16) -> bool
fn le(&self, other: &f16) -> bool
self
and other
) and is used by the <=
operator. Read more1.0.0 · source§impl Rem for f16
impl Rem for f16
The remainder from the division of two floats.
The remainder has the same sign as the dividend and is computed as:
x - (x / y).trunc() * y
.
§Examples
let x: f32 = 50.50;
let y: f32 = 8.125;
let remainder = x - (x / y).trunc() * y;
// The answer to both operations is 1.75
assert_eq!(x % y, remainder);
Run1.22.0 · source§impl RemAssign<&f16> for f16
impl RemAssign<&f16> for f16
source§fn rem_assign(&mut self, other: &f16)
fn rem_assign(&mut self, other: &f16)
%=
operation. Read more1.8.0 · source§impl RemAssign for f16
impl RemAssign for f16
source§fn rem_assign(&mut self, other: f16)
fn rem_assign(&mut self, other: f16)
%=
operation. Read more1.22.0 · source§impl SubAssign<&f16> for f16
impl SubAssign<&f16> for f16
source§fn sub_assign(&mut self, other: &f16)
fn sub_assign(&mut self, other: &f16)
-=
operation. Read more1.8.0 · source§impl SubAssign for f16
impl SubAssign for f16
source§fn sub_assign(&mut self, other: f16)
fn sub_assign(&mut self, other: f16)
-=
operation. Read more