[plt-dev] range mini benchmark

On May  2, David Van Horn wrote:
> Here is a benchmark for a few implementations of `range':
> 
>     Nat Nat -> [Listof Nat]
>     (range 0 5) => (list 0 1 2 3 4 5)
>     (range 5 0) => (list 5 4 3 2 1 0)
> 
> One uses build-list, another uses sequences.  I threw in an 
> implementation using an iterative build-list as well.
> 
> I was surprised the build-list version beat out sequences -- thoroughly, 
> with the iterative build-list being an improvement over the built in 
> recursive one.

This:

  (define (range-seq L H)
    (for/list ((i (if (>= H L) 
                      (in-range L (+ H 1)) 
                      (in-range L (- H 1) -1)))) i))

forces creating a sequence value, and this:

  (define (range-seq L H)
    (for/list ((i (in-range L (+ H 1)))) i))

doesn't, so it is much faster.

Also, this kind of test is tricky to measure -- the number that you'd
want is the runtime minus the GC time -- but only the GC for the
resulting list.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!