pulp is a safe abstraction over SIMD instructions, that allows you to write a function once
and dispatch to equivalent vectorized versions based on the features detected at runtime.
Autovectorization example
use pulp::Arch;
let mut v = (0..1000).map(|i| i as f64).collect::<Vec<_>>();
let arch = Arch::new();
arch.dispatch(|| {
for x in &mut v {
*x *= 2.0;
}
});
for (i, x) in v.into_iter().enumerate() {
assert_eq!(x, 2.0 * i as f64);
}Manual vectorization example
use pulp::{Arch, Simd, WithSimd};
struct TimesThree<'a>(&'a mut [f64]);
impl<'a> WithSimd for TimesThree<'a> {
type Output = ();
#[inline(always)]
fn with_simd<S: Simd>(self, simd: S) -> Self::Output {
let v = self.0;
let (head, tail) = S::f64s_as_mut_simd(v);
let three = simd.f64s_splat(3.0);
for x in head {
*x = simd.f64s_mul(three, *x);
}
for x in tail {
*x = *x * 3.0;
}
}
}
let mut v = (0..1000).map(|i| i as f64).collect::<Vec<_>>();
let arch = Arch::new();
arch.dispatch(TimesThree(&mut v));
for (i, x) in v.into_iter().enumerate() {
assert_eq!(x, 3.0 * i as f64);
}