Awesome. Thanks!
On Tuesday, January 7, 2014 6:40:42 AM UTC-5, Tim Holy wrote:
>
> On Monday, January 06, 2014 07:00:45 PM Brendan O'Connor wrote:
> > That's in the case where your code asserts the type, correct?
>
> Yes, or when Julia can infer the type on its own.
>
> > I think the following might illustrate what I'm wondering.
> > Say arr::Array{A}, and odd elements have type B but even elements have
> C.
> >
> > This is slow, right?
> > for i=1:2:length(arr) arr[i].x end
>
> Yes.
>
> > Will this be fast? Can Julia get away with only having to assert a
> > typecheck, which hopefully is fast?
> > for i=1:2:length(arr) (arr[i]::B).x end
>
> Right again.
>
> You probably know this as well, but just in case: Julia optimizes at the
> function level, so even though your first example would be slow, let's say
> that
> instead the inner loop contains
>
> some_big_computation_in_a_function(arr[i])
>
> Once Julia figured out arr[i]'s actual type and called the appropriate
> method,
> the actual computation itself would be fast.
>
> --Tim
>
>
