On Sun, Jan 4, 2009 at 6:35 PM, mabshoff <mabsh...@googlemail.com> wrote: > > > > On Jan 4, 6:21 pm, "William Stein" <wst...@gmail.com> wrote: >> On Sun, Jan 4, 2009 at 5:38 PM, Justin C. Walker <jus...@mac.com> wrote: > > Hi, > > <SNIP> > >> I built on a CentOS 64-bit system with 1GB RAM, and a test in arith.py >> fails due to swapping leading to a timeout. The test in question is a >> *massive* performance regression, I think caused by a patch of Craig >> Citro. I've created a blocker ticket for this here: > > Hmm, do you mean > > changeset: 10906:5af5af172db9 > user: Craig Citro <craigci...@gmail.com> > date: Wed Nov 05 02:04:21 2008 -0800 > summary: Speed up prime_range, massive arith cleanup. See trac > #4443. > > I am under the impression that Craig added a bunch of doctests > including this one, but I could be wrong. > >> http://trac.sagemath.org/sage_trac/ticket/4939 >> >> I've posted a patch there, and hope somebody will review it (hint, >> hint: Craig.) > > :) > >> I think this should be a blocker since it prevents doctests pass on >> what I view as a supported platform (namely 64-bit machines with <= >> 1GB RAM). > > Yep, and I agree that we should not be using pari for this. I cannot > believe that this doesn't expose a bug in pari, so if someone has > 2.3.4svn or 2.4.3svn handy please check out if this is still a problem > and report it upsream if that is the case.
Actually in all cases we use pari for this -- it's just that for some reason when we *don't* convert from pari back to sage, there is a massive slowdown. Yes, you read that right. It's very counterintuitive! There is more to #4939 that should be investigated. I've had some undergrad student(s) do projects on implementing a faster prime_range command not using pari, but they've never succeeded. I wish somebody would do this right at some point, e.g., using something like the Sieve of Atkin. -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
