How should I get the add assign trait to work for a vector within a struct?

New to rust. Would like to understand why this issue is occuring and how to fix. I don't think I can change the signature for the implementation of the trait method either which makes this more harder to fix.

use std::ops::{AddAssign};

pub struct ColumnVector {
    pub data: Vec<f32>
}

impl AddAssign for &ColumnVector {
    fn add_assign(&mut self, other: Self) {
        for (index, elem) in other.data.iter().enumerate() {
            self.data[index] += elem;
        }
    }
}

fn main() {
    
}

Using the & creates an immutable reference to ColumnVector and its fields, so you cannot get a mutable reference to update it.

You could do:

pub struct ColumnVector {
    pub data: Vec<f32>
}


impl AddAssign for &mut ColumnVector {
    fn add_assign(&mut self, other: Self) {
        for (index, elem) in other.data.iter().enumerate() {
            self.data[index] += elem;
        }
    }
}

fn main() {
    
}

if you needed the borrow, but you probably just want to remove the & entirely.

For context:

You can either have n-number of immutable borrows, or a single mutable one. There are ways around this (read about interior mutability) but generally you must have exclusive access to a variable to change it.

When you borrowed ColumnVector, you could not later edit the field because you did not own the data.