Hi!
Juhani Viheräkoski <[email protected]> writes:
> With recent changes in guile vm there are lots on improvements on the
> Gambit benchmarks.
Improvements compared to what?
> In the worst case some test run 10% slower
Slower than what?
> but there are huge wins in testcases involving vectors offsetting
> this.
Oh, that's cool, but it feels like we're slightly cheating on these.
;-)
> (define (ack m n)
> (cond ((= m 0) (+ n 1))
> ((= n 0) (ack (- m 1) 1))
> (else (ack (- m 1) (ack m (- n 1))))))
>
> (ack 3 9)
This is not tail-recursive (because of the nested `ack' call in the
`else' clause), which is why it can lead to a stack overflow.
I'm too stupid to compute the maximum "depth" of the call graph, but it
looks like this:
(ack 3 9)
(ack 3 8) <--- X
(ack 3 7)
...
(ack 3 0)
(ack 2 0)
...
(ack 0 0)
(ack 2 X)
(ack 2 (- X 1)) <--- Y
...
(ack 1 Y)
(ack 1 (- Y 1))
...
Thanks,
Ludo'.
