Re: Comparaison between PARI MPQS, PPMPQS and PPSIGS

[Igor Schein <igor@txc.com>]

On Wed, Nov 27, 2002 at 05:26:39PM +0100, Bill Allombert wrote:
> Hello developers,
> 
> I have factored 
> 117433370311644622074182931512170893877890957626285922622753078073774028918529
> (78 digits)
> 
> on a 1GHz PIV
> with PARI (2.2.5), and then I try PPMPQS (2.8) and PPSIGS (1.1) from 
> http://www.asahi-net.or.jp/~KC2H-MSM/cn/
> 
> here the running time:
> PARI   : 3h 9 min
> PPMPQS : 1h 58 min
> PPSIGS : 1h 46 min
> 
> Karim's FAQ states 
> 
> > PARI's MPQS is about as fast as PPMPQS-2.7 in the 60 digits range, and much
> > slower afterwards, e.g already 3 times slower for 70 digits. We have not
> > tested mpqs4linux.
> 
> but PARI performs better in this test.
 
Gerhard is a *righter* person than myself to comment on it, but I just
wanna mention that performance of PARI's MPQS *heavily* depends on L2
cache size and speed, as well as current system activity, and greatly
varies between architectures and platforms.  I can't speak for factors
effecting PPxxxx speed, but I expect the performance ratio to be even
smaller on 2.4 GHz Xeon, which I'll be trying myself shortly.

Igor