So I need to compute the exponential function, where the exponent is a Matrix. Since I am using the ndarray crate, and didn’t find an implementation for, e.g., exp(H), where H is the matrix.
I stumbled upon the expm crate.

However I wasn’t able to get it to work. I always get the error:

arguments to this function are incorrect
ArrayBase<OwnedRepr<_>, Dim<...>> and ArrayBase<_, Dim<[usize; 2]>> have similar names, but are actually distinct types
perhaps two different versions of crate ndarray are being used?
ArrayBase<OwnedRepr<f64>, Dim<...>> and ArrayBase<_, Dim<[usize; 2]>> have similar names, but are actually distinct types
perhaps two different versions of crate ndarray are being used?

My code:

use ndarray::*;
use ndarray_rand::rand_distr::num_traits::Pow;

extern crate openblas_src;


fn main() {

    let d: usize =   3;

    let eye: AArrayBase<ndarray::OwnedRepr<f64>, Dim<[usize; 2]>>  = Array::eye(d);
    let mut b: ArrayBase<ndarray::OwnedRepr<f64>, Dim<[usize; 2]>> = Array::eye(d);

    expm::expm(&eye, &mut b);
 

}

I am on a windows system and use vscode for development. I installed/compiled openblas-src, following the crate discription.

I followed the example on expm the crate page. Yet it doesn’t work. Since I am fairly new to rust, my inexperience could be the cause of it.

What am I doing wrong here?

Might there be a better crate (that has more recent updates than expm) to get this functionality ?