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//! Implements vertical (lane-wise) floating-point `rsqrte`.
macro_rules! impl_math_float_rsqrte {
([$elem_ty:ident; $elem_count:expr]: $id:ident | $test_tt:tt) => {
impl $id {
/// Reciprocal square-root estimate: `~= 1. / self.sqrt()`.
///
/// FIXME: The precision of the estimate is currently unspecified.
#[inline]
pub fn rsqrte(self) -> Self {
unsafe {
use crate::llvm::simd_fsqrt;
$id::splat(1.) / Simd(simd_fsqrt(self.0))
}
}
}
test_if!{
$test_tt:
paste::item! {
pub mod [<$id _math_rsqrte>] {
use super::*;
#[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
fn rsqrte() {
use crate::$elem_ty::consts::SQRT_2;
let tol = $id::splat(2.4e-4 as $elem_ty);
let o = $id::splat(1 as $elem_ty);
let error = (o - o.rsqrte()).abs();
assert!(error.le(tol).all());
let t = $id::splat(2 as $elem_ty);
let e = 1. / SQRT_2;
let error = (e - t.rsqrte()).abs();
assert!(error.le(tol).all());
}
}
}
}
};
}