Fortran's the only obstacle to purchasing M1 for me currently.

A while ago I compared the execution time for some simple matrix arithmetic in rust, fortran (2003 I think), and python/numpy. (as an aside: as far as science is concerned, python without numpy doesn't exist.) Execution times were fairly similar.

What I didn't mention was the pretty-much-optimal fortran and python solutions took maybe a minute to code.

The optimal Rust solution took over a day.

I'll also note intent(in), intent(out) fulfil similar uses to '&' and '&mut'.