Unify two Real types into one that is precise enough

[gnzlbg]

Given:

fn add<T: Real, U: Real>(x: T, y: U) -> ??? {
  x + y
}

I'd like to fill the ??? with either T or U, depending which one is wider. What's the alga way of unifying Reals in computations?

[sebcrozet]

alga does not unify computations between two distinct types. Such unification rules would be very application-specific. So alga won't cover this use-case. Perhaps it will be supported in the future when specialization is possible in Rust in order to allow users to specialize their own unification rules whenever the default one provided by alga does not fit.

So right now your only option is to implement Add for your types and add a trait bound:

fn add<T: Real + Add<U>, U: Real>(x: T, y: U) -> T::Output {
  x + y
}

[WaDelma]

Or you can convert either x to U or y to U.