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author | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
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committer | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
commit | 1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch) | |
tree | 7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/num-traits/src/ops/mul_add.rs | |
parent | 5ecd8cf2cba827454317368b68571df0d13d7842 (diff) | |
download | fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip |
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/num-traits/src/ops/mul_add.rs')
-rw-r--r-- | vendor/num-traits/src/ops/mul_add.rs | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/num-traits/src/ops/mul_add.rs b/vendor/num-traits/src/ops/mul_add.rs new file mode 100644 index 0000000..51beb55 --- /dev/null +++ b/vendor/num-traits/src/ops/mul_add.rs @@ -0,0 +1,149 @@ +/// Fused multiply-add. Computes `(self * a) + b` with only one rounding +/// error, yielding a more accurate result than an unfused multiply-add. +/// +/// Using `mul_add` can be more performant than an unfused multiply-add if +/// the target architecture has a dedicated `fma` CPU instruction. +/// +/// Note that `A` and `B` are `Self` by default, but this is not mandatory. +/// +/// # Example +/// +/// ``` +/// use std::f32; +/// +/// let m = 10.0_f32; +/// let x = 4.0_f32; +/// let b = 60.0_f32; +/// +/// // 100.0 +/// let abs_difference = (m.mul_add(x, b) - (m*x + b)).abs(); +/// +/// assert!(abs_difference <= 100.0 * f32::EPSILON); +/// ``` +pub trait MulAdd<A = Self, B = Self> { + /// The resulting type after applying the fused multiply-add. + type Output; + + /// Performs the fused multiply-add operation `(self * a) + b` + fn mul_add(self, a: A, b: B) -> Self::Output; +} + +/// The fused multiply-add assignment operation `*self = (*self * a) + b` +pub trait MulAddAssign<A = Self, B = Self> { + /// Performs the fused multiply-add assignment operation `*self = (*self * a) + b` + fn mul_add_assign(&mut self, a: A, b: B); +} + +#[cfg(any(feature = "std", feature = "libm"))] +impl MulAdd<f32, f32> for f32 { + type Output = Self; + + #[inline] + fn mul_add(self, a: Self, b: Self) -> Self::Output { + <Self as crate::Float>::mul_add(self, a, b) + } +} + +#[cfg(any(feature = "std", feature = "libm"))] +impl MulAdd<f64, f64> for f64 { + type Output = Self; + + #[inline] + fn mul_add(self, a: Self, b: Self) -> Self::Output { + <Self as crate::Float>::mul_add(self, a, b) + } +} + +macro_rules! mul_add_impl { + ($trait_name:ident for $($t:ty)*) => {$( + impl $trait_name for $t { + type Output = Self; + + #[inline] + fn mul_add(self, a: Self, b: Self) -> Self::Output { + (self * a) + b + } + } + )*} +} + +mul_add_impl!(MulAdd for isize i8 i16 i32 i64 i128); +mul_add_impl!(MulAdd for usize u8 u16 u32 u64 u128); + +#[cfg(any(feature = "std", feature = "libm"))] +impl MulAddAssign<f32, f32> for f32 { + #[inline] + fn mul_add_assign(&mut self, a: Self, b: Self) { + *self = <Self as crate::Float>::mul_add(*self, a, b) + } +} + +#[cfg(any(feature = "std", feature = "libm"))] +impl MulAddAssign<f64, f64> for f64 { + #[inline] + fn mul_add_assign(&mut self, a: Self, b: Self) { + *self = <Self as crate::Float>::mul_add(*self, a, b) + } +} + +macro_rules! mul_add_assign_impl { + ($trait_name:ident for $($t:ty)*) => {$( + impl $trait_name for $t { + #[inline] + fn mul_add_assign(&mut self, a: Self, b: Self) { + *self = (*self * a) + b + } + } + )*} +} + +mul_add_assign_impl!(MulAddAssign for isize i8 i16 i32 i64 i128); +mul_add_assign_impl!(MulAddAssign for usize u8 u16 u32 u64 u128); + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn mul_add_integer() { + macro_rules! test_mul_add { + ($($t:ident)+) => { + $( + { + let m: $t = 2; + let x: $t = 3; + let b: $t = 4; + + assert_eq!(MulAdd::mul_add(m, x, b), (m*x + b)); + } + )+ + }; + } + + test_mul_add!(usize u8 u16 u32 u64 isize i8 i16 i32 i64); + } + + #[test] + #[cfg(feature = "std")] + fn mul_add_float() { + macro_rules! test_mul_add { + ($($t:ident)+) => { + $( + { + use core::$t; + + let m: $t = 12.0; + let x: $t = 3.4; + let b: $t = 5.6; + + let abs_difference = (MulAdd::mul_add(m, x, b) - (m*x + b)).abs(); + + assert!(abs_difference <= 46.4 * $t::EPSILON); + } + )+ + }; + } + + test_mul_add!(f32 f64); + } +} |