Maxima/Ecl on 32-bit machine cannot evaluate "apply(union, listify({{..}}))"
Subject: Maxima/Ecl on 32-bit machine cannot evaluate "apply(union, listify({{..}}))"
From: Stavros Macrakis
Date: Thu, 4 Sep 2008 12:58:41 -0400
Oliver,
Given the recent bug we found, I'd be interested to learn what sort of
speedup you see in your application with the patch + tree_reduce. I suspect
it will be dramatic.
-s
On Thu, Sep 4, 2008 at 12:29 PM, Oliver Kullmann
<O.Kullmann at swansea.ac.uk>wrote:
> > We stopped using xreduce for big unions, since for some our applications
> it
> > > had
> > > a big effect --- 5 hours instead of 1 hour where you need to do a lot
> of
> > > experimentations
> > > is not good.
> > >
> >
> > It sounds as though we should improve the performance of xreduce. In
> > particular, it ought to use apply internally up to the limit of the
> > underlying implementation, to take full advantage of the underlying
> > implementation while keeping the code portable. By the way, depending on
> > the patterns in your data, you may also wish to try lreduce, rreduce, and
> > tree_reduce; sometimes there are big differences in the performance of
> the
> > three.
> >
> > l r tree
> > append 7.63 0.97 0.02 -- [a,b,c] -- apply will be even faster
> > union 3.28 3.12 0.18 -- {random(100)}
> >
> > -s
>
> I see; I'm glad to see that something happens with the set-operations,
> so I'll wait a bit what comes out of it, and then will revise my
> code accordingly.
>
> Thanks!
>
> Oliver
>
>