On Dec 16, 2008, at 07:44 , William Stein wrote:
> > On Tue, Dec 16, 2008 at 7:41 AM, Justin C. Walker <[email protected]> > wrote: >> >> >> On Dec 16, 2008, at 07:17 , William Stein wrote: >> >>> >>> On Tue, Dec 16, 2008 at 12:50 AM, achrzesz <[email protected]> wrote: >>>> >>>> Hallo, >>>> I'm wondering what goes wrong with tis: >>>> >>>> (sage 3.2 compiled from sources, ubuntu 8.04, quad core 2.4 GHz) >>>> >>>> >>>> sage: for k in range(14,21): >>>> ....: f=2^2^k+1;w=ecm.find_factor(f);[w[0],prod(w)==f] >>>> ....: >>>> [2, False] >>>> [523923, False] >>>> [1901173, False] >>>> [2, False] >>>> [2, False] >>>> [30539, False] >>>> [2, False] >>>> >>>> Are the exponents to big? >>>> >>>> Andrzej Chrzeszczyk >>> >>> Yes, I think there must be a hard limit on the input line for GMP- >>> ECM. >>> If I try the first number directly on the command line, it says >>> "Factor found in step 1: 2". However the first number is *odd*, >>> so 2 >>> can't be a factor! >>> What's really happening is that GMP-ECM is ignoring everything after >>> the first 4095 digits when I paste the input in. >> >> I think you are running into a system limit, not an ECM limit. Even >> emacs seems to have a problem when I paste in "2^2^14+1". >> >> I finally got this to work by doing >> >> f = open("/tmp/foo", "w") >> print >> f, 2^2^14+1 >> f.close() >> >> in Sage, and then >> >> ecm < /tmp/foo >> >> in the shell: >> >> $ ecm 10000000 100000 < /tmp/foo >> GMP-ECM 6.1.3 [powered by GMP 4.2.1] [ECM] >> Input number has 4933 digits >> Using B1=10000000, B2=100000, polynomial x^1, sigma=3668583302 >> ... >> >> It's likely that the "expect" interface is running into the same >> limit, since it uses the tty sub-system. >> >> All those "bings" are a signal from the system (tty driver) that it's >> choking, and isn't reading what you are throwing at it. > > Yes, I agree that is likely what is happening. In fact, most ptty > interfaces in sage would simply freeze given that many characters of > input, which is why they all use files when given more than about 2000 > characters input. > >> http://trac.sagemath.org/sage_trac/ticket/4814 > > I posted a patch there that does some error checking at least. It's > minimal. I hope somebody will referee it asap so it can go in > sage-3.2.2. I looked it over and added a comment to the Trac report (don't use "4095"; use a smaller number instead). Justin -- Justin C. Walker, Curmudgeon-at-Large () The ASCII Ribbon Campaign /\ Help Cure HTML Email --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
