90 lines
1.7 KiB
Rust
90 lines
1.7 KiB
Rust
use core::ops::{Add, Mul, Neg};
|
|
|
|
pub fn abs<T>(x: T) -> T
|
|
where
|
|
T: PartialOrd + Default + Neg<Output = T>,
|
|
{
|
|
if x >= T::default() {
|
|
x
|
|
} else {
|
|
-x
|
|
}
|
|
}
|
|
|
|
// These are implemented here because core::f32 doesn't have them (yet).
|
|
// They are naive and don't handle inf/nan.
|
|
// `compiler-intrinsics`/llvm should have better (robust, universal, and
|
|
// faster) implementations.
|
|
|
|
pub fn copysign<T>(x: T, y: T) -> T
|
|
where
|
|
T: PartialOrd + Default + Neg<Output = T>,
|
|
{
|
|
if (x >= T::default() && y >= T::default())
|
|
|| (x <= T::default() && y <= T::default())
|
|
{
|
|
x
|
|
} else {
|
|
-x
|
|
}
|
|
}
|
|
|
|
#[cfg(not(feature = "nightly"))]
|
|
pub fn max<T>(x: T, y: T) -> T
|
|
where
|
|
T: PartialOrd,
|
|
{
|
|
if x > y {
|
|
x
|
|
} else {
|
|
y
|
|
}
|
|
}
|
|
|
|
#[cfg(not(feature = "nightly"))]
|
|
pub fn min<T>(x: T, y: T) -> T
|
|
where
|
|
T: PartialOrd,
|
|
{
|
|
if x < y {
|
|
x
|
|
} else {
|
|
y
|
|
}
|
|
}
|
|
|
|
#[cfg(feature = "nightly")]
|
|
pub fn max(x: f32, y: f32) -> f32 {
|
|
core::intrinsics::maxnumf32(x, y)
|
|
}
|
|
|
|
#[cfg(feature = "nightly")]
|
|
pub fn min(x: f32, y: f32) -> f32 {
|
|
core::intrinsics::minnumf32(x, y)
|
|
}
|
|
|
|
// Multiply-accumulate vectors `x` and `a`.
|
|
//
|
|
// A.k.a. dot product.
|
|
// Rust/LLVM optimize this nicely.
|
|
pub fn macc<T>(y0: T, x: &[T], a: &[T]) -> T
|
|
where
|
|
T: Add<Output = T> + Mul<Output = T> + Copy,
|
|
{
|
|
x.iter()
|
|
.zip(a)
|
|
.map(|(x, a)| *x * *a)
|
|
.fold(y0, |y, xa| y + xa)
|
|
}
|
|
|
|
pub fn macc_i32(y0: i32, x: &[i32], a: &[i32], shift: u32) -> i32 {
|
|
// Rounding bias, half up
|
|
let y0 = ((y0 as i64) << shift) + (1 << (shift - 1));
|
|
let y = x
|
|
.iter()
|
|
.zip(a)
|
|
.map(|(x, a)| *x as i64 * *a as i64)
|
|
.fold(y0, |y, xa| y + xa);
|
|
(y >> shift) as i32
|
|
}
|