SIMD support

[ManevilleF]

hexx should provide optional SIMD operations like glam.

SIMD: Single instruction, multiple data (SIMD) instructions can be used to perform the same operation on multiple data elements simultaneously. Rust's packed_simd crate provides support for SIMD instructions and could be used to accelerate certain operations in hexx.

I don't know what would be better, wait for stabilization of std::simd (issue) or use packed_simd.

In terms of API I don't know what is better:

• A HexA type with simd support
• Add a simd module with explicit simd methods like that:

use super::Hex;
use std::simd::i32x2;
// src/hex/simd.rs

impl Hex {
    pub fn simd_add(self, rhs: Self) -> Self {
        let x = i32x2::from_array([self.x, rhs.x]);
        let y = i32x2::from_array([self.y, rhs.y]);
        let [x, y] = (x + y).to_array();
        Self::new(x, y)
    }
}

[SpecificProtagonist]

Afaik packed_simd_2 is a pre- const generics design and not planed for inclusion in std anymore. As it requires nightly anyways I don't see a reason to use it instead of core::simd.

[ManevilleF]

There is also the wide crate, used by bevy_rapier, worth exploring probably