pub trait Floating: Numeric + LowerExp + UpperExp + Neg + From<f32> + From<i8> + From<i16> + From<u8> + From<u16> {
type Raw: Unsigned;
Show 30 associated constants and 14 methods
const RADIX: u32;
const MANTISSA_DIGITS: u32;
const DIGITS: u32;
const EPSILON: Self;
const MIN: Self;
const MIN_POSITIVE: Self;
const MAX: Self;
const MIN_EXP: i32;
const MAX_EXP: i32;
const MIN_10_EXP: i32;
const MAX_10_EXP: i32;
const NAN: Self;
const INFINITY: Self;
const NEG_INFINITY: Self;
const PI: Self;
const FRAC_PI_2: Self;
const FRAC_PI_3: Self;
const FRAC_PI_4: Self;
const FRAC_PI_6: Self;
const FRAC_PI_8: Self;
const FRAC_1_PI: Self;
const FRAC_2_PI: Self;
const FRAC_2_SQRT_PI: Self;
const SQRT_2: Self;
const FRAC_1_SQRT_2: Self;
const E: Self;
const LOG2_E: Self;
const LOG10_E: Self;
const LN_2: Self;
const LN_10: Self;
// Required methods
fn is_nan(self) -> bool;
fn is_infinite(self) -> bool;
fn is_finite(self) -> bool;
fn is_normal(self) -> bool;
fn classify(self) -> FpCategory;
fn is_sign_positive(self) -> bool;
fn is_sign_negative(self) -> bool;
fn recip(self) -> Self;
fn to_degrees(self) -> Self;
fn to_radians(self) -> Self;
fn max(self, other: Self) -> Self;
fn min(self, other: Self) -> Self;
fn to_bits(self) -> Self::Raw;
fn from_bits(bits: Self::Raw) -> Self;
}
Expand description
Declare that a type is a floating-point number.
Required Associated Types§
Required Associated Constants§
sourceconst MANTISSA_DIGITS: u32
const MANTISSA_DIGITS: u32
Number of significant digits in base 2.
sourceconst EPSILON: Self
const EPSILON: Self
Machine epsilon value for f32
.
This is the difference between 1.0
and the next larger representable
number.
sourceconst MIN_POSITIVE: Self
const MIN_POSITIVE: Self
Smallest positive normal f32
value.
sourceconst MIN_10_EXP: i32
const MIN_10_EXP: i32
Minimum possible normal power of 10 exponent.
sourceconst MAX_10_EXP: i32
const MAX_10_EXP: i32
Maximum possible power of 10 exponent.
sourceconst NEG_INFINITY: Self
const NEG_INFINITY: Self
Negative infinity (−∞).
sourceconst FRAC_2_SQRT_PI: Self
const FRAC_2_SQRT_PI: Self
2/sqrt(π)
sourceconst FRAC_1_SQRT_2: Self
const FRAC_1_SQRT_2: Self
1/sqrt(2)
Required Methods§
sourcefn is_infinite(self) -> bool
fn is_infinite(self) -> bool
Returns true
if this value is positive infinity or negative infinity,
and false
otherwise.
sourcefn is_normal(self) -> bool
fn is_normal(self) -> bool
Returns true
if the number is neither zero, infinite, subnormal, or
NaN
.
sourcefn classify(self) -> FpCategory
fn classify(self) -> FpCategory
Returns the floating point category of the number. If only one property is going to be tested, it is generally faster to use the specific predicate instead.
sourcefn is_sign_positive(self) -> bool
fn is_sign_positive(self) -> bool
Returns true
if self
has a positive sign, including +0.0
, NaN
s
with positive sign bit and positive infinity.
sourcefn is_sign_negative(self) -> bool
fn is_sign_negative(self) -> bool
Returns true
if self
has a negative sign, including -0.0
, NaN
s
with negative sign bit and negative infinity.
sourcefn to_degrees(self) -> Self
fn to_degrees(self) -> Self
Converts radians to degrees.
sourcefn to_radians(self) -> Self
fn to_radians(self) -> Self
Converts degrees to radians.
sourcefn to_bits(self) -> Self::Raw
fn to_bits(self) -> Self::Raw
Raw transmutation to u32
.
This is currently identical to transmute::<f32, u32>(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.
sourcefn from_bits(bits: Self::Raw) -> Self
fn from_bits(bits: Self::Raw) -> Self
Raw transmutation from u32
.
This is currently identical to transmute::<u32, f32>(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.