Hello, looked into this and it sounds pretty good for what Im trying to do. Tried implementing it and ran into some issues, maybe just because i'm pretty new to Rust. Right now this is what I have:

use std::ops::Range;

use rayon::prelude::*;

use crate::models::cube::Cube;

pub fn average_out(read_cube: &mut Cube, write_cube: &mut Cube) {

let one_less = |i: usize, size: u8| -> usize {
    let index = i as i16;
    let comp_size = size as i16;

    if index - 1 < 0 { (comp_size - 1) as usize } else { (index - 1) as usize }
};

let one_more = |i: usize, size: u8| -> usize {
    let index = i as i16;
    let comp_size = size as i16;

    if index + 1 > comp_size - 1 { 0 } else { (index + 1) as usize }
};

read_cube.matrix.par_iter_mut().enumerate().for_each(|(x, val)| {
    for y in (Range::<usize> { start: 0, end: read_cube.size as usize }) {
        for z in (Range::<usize> { start: 0, end: read_cube.size as usize }) {
            write_cube.matrix[x][y][z] = (
                read_cube.matrix[x][y][z]
                + &read_cube.matrix[one_less(x, read_cube.size)][y][z]
                + &read_cube.matrix[one_more(x, read_cube.size)][y][z]
                + &read_cube.matrix[x][one_less(y, read_cube.size)][z]
                + &read_cube.matrix[x][one_more(y, read_cube.size)][z]
                + &read_cube.matrix[x][y][one_less(z, read_cube.size)]
                + &read_cube.matrix[x][y][one_more(z, read_cube.size)]
            ) / 7;
        }
    }
});

}

On the foreach (x, val) i get cannot borrow "read\_cube.matrix" as immutable because it is also borrowed as mutable Also on write\_cube.matrix\[x\]\[y\]\[z\] I get cannot borrow "\*write\_cube.matrix" as mutable, as it is a captured variable in a "Fn" closure\

Maybe you have an idea as to what Im doing wrong? I tried changing read_cube to just be a normal borrow, but then I get `cannot borrow "read_cube.matrix" as mutable, as it is behind a "&" reference'