[Axiom-developer] Re: [Axiom-mail] A slow summation

[Bill Page]

On 15 Jun 2007 07:49:11 +0200, Martin Rubey wrote:
> > > reduce(+,[1.0/i for i in 1..20000])
> > >
> > > This works, but is (I think) unreasonably slow; it takes over 21 seconds on
> > > my computer.  The equivalent command in Maxima takes less than 1 second.
>
> Bill, could you file that as a bug on MathAction, please.

Well, I would rather that somebody new do that. Alasdair? :-)

The "issue" (I am not quite sure to call it a "bug") is probably some
very inefficient implementation of list comprehension in the Axiom
interpreter. E.g.

(1) -> )set message time on
(1) -> [i for i in 1..20000];

                                              Type: List PositiveInteger
     Time: 14.73 (EV) + 0.02 (OT) + 0.05 (GC) = 14.80 sec

(2) -> expand(1..20000);

                                                          Type: List Integer
                            Time: 0.07 (IN) + 0.18 (OT) = 0.25 sec

-------

Both (1) and (2) do essentially the same thing.

> (If you have an sbcl compiled axiom available, you could check
> whether it is gcl's fault, or rather a bug in axiom.)

I am quite sure that this is not a lisp implementation issue,
but no I don't have a sbcl version of Axiom available. Do you?
Still, maybe this is a job for someone who knows how to use
the sbcl profiler to find out where the Axiom interpreter is
spending all it's time - Waldek?

Regards,
Bill Page.