performance of ndarray arithmetic operation

[tyghl]

i want to perform an Add operation and assign the result to another array.
like this:

result.assign(&(&arr1+ &arr2));

since i don't want to consume the data in arr1 and arr2, i think this method will always generate a temporary array, hence bad for performance.
So should i use iterator and add seperately in this case? Does any better solution exist?

[bluss]

First consider result += &arr1; result += &arr2; if you need something custom, you can do it with Zip without creating any intermediate array.

[jturner314]

Both of those are good suggestions. Using two separate add-assign operations requires two separate loops over the elements, while Zip/azip! does it in a single loop over the elements. Here's an example with the azip! macro:

use ndarray::azip;
use ndarray::prelude::*;

fn main() {
    let arr1 = array![1, -4, 7];
    let arr2 = array![6, 8, -2];
    let mut result = Array1::zeros(3);
    azip!((r in &mut result, &a1 in &arr1, &a2 in &arr2) *r = a1 + a2);
    println!("{}", result);
}

(Rust Playground)

[tyghl]

Thank you very much! Zip is exactly what i want!