If you want to make that fast, you need to wrap that inside a function, using
a separate name for each user-supplied f. Example:
function sumf_with_sinc_plus_x(xs)
@sumf(sinc_plus_x, xs)
end
function sumf_with_exp(xs)
@sumf(exp, xs)
end
If you don't wrap it in a function, then it runs in global scope, and that's
horribly slow.
My version allows you to pass a function as an argument, and mimics what it
would be like if we could pass functions-as-arguments without a performance
penalty.
--Tim
On Saturday, May 17, 2014 05:03:07 AM Mike Innes wrote:
> I may be missing the point here, but wouldn't it be easier to define sumf
> as a macro?
>
> macro sumf(f, xs)
> quote
> s = 0.0
> x = $(esc(xs))
> for i = 1:length(x)
> s += $(esc(f))(x[i])
> end
> s
> end
> end
>
> @sumf(sinc_plus_x, x)
>
> This is just as fast and has the advantage that it will work when f is only
> in the local scope.
>
> On Saturday, 17 May 2014 11:50:56 UTC+1, Tim Holy wrote:
> > On Friday, May 16, 2014 02:36:03 PM [email protected]
<javascript:>wrote:
> > > - The solver need to be fast and for that, inlining is of paramount
> > > importance. I know that there is no way to inline F for the time being.
> >
> > Do
> >
> > > we expect inlining on function argument in the near future of Julia ?
> >
> > I can't speak for when this will happen in a "nice" way, but using Julia's
> > metaprogramming capabilities there is a (somewhat ugly) way to get what
> > you
> > want. Since I'm planning to use this trick myself shortly, I created a
> > little
> > demonstration:
> >
> > https://gist.github.com/timholy/bdcee95f9b7725214d8b
> >
> > If you prefer, you don't have to separate out the definition of the body
> > from
> > the eval(quote...end) part, I just did it that way to better illustrate
> > the
> > separate ideas.
> >
> > --Tim
