Arithmetic with references

[jedbrown]

In various circumstances, including with iterators such as below, you're holding a reference and would like to perform arithmetic.

let velocity = [Velocity::meters_per_second(5.0); 3];
let energy = 0.5 * velocity.iter().map(|v| v * v).sum::<SpecificEnergy>();

This works in Diman if one writes the closure as |v| *v * *v, but the above works with nondimensional types and is less visually noisy. Should arithmetic (Add, Sub, Mul, Div) be implemented for all four combinations in which one or both of the args are references?

Yes, this case also works with |v| v.powi::<2>().

[Tehforsch]

This is a good idea. I think anything that works with floats and that we can support should be supported, so I'd like to add this.

[Tehforsch]

Done in #53. Your example:

let velocity = [Velocity::meters_per_second(5.0); 3];
let energy = 0.5 * velocity.iter().map(|v| v * v).sum::<SpecificEnergy>();

now compiles.

[jedbrown]

Wonderful, thanks!