The bug also occurs on Sage 5.7, and a quick-and-dirty bisection
script shows that n = 46341 does work and n = 46342 does not. Since
46341 is almost exactly the square root of 2^{31}, and the relevant
bits of code seem to use C int variables rather than Sage integers
(presumably for speed reasons), it looks like an integer overflow.David On 27 February 2013 17:17, John Cremona <john.crem...@gmail.com> wrote: > Try asking Bosman directly; I don't know if he reads this list. > > John > > On 27 February 2013 15:23, Peng <tianpeng.ch...@gmail.com> wrote: >> Dear John Cremona, >> Thanks for your reply. >> >> For n=45000 or smaller, it works well and gives an output. Then the next >> number I tried is 50000 and this gave an Error. >> >> In sage 5.7, this doesn't work neither. >> >> I even don't know yet why this happens exactly. >> >> PS: >> I'm trying to compute the modular Galois represtations of Ramanujan tau >> function using the algorithm by Johan Bosman, which requests a huge >> precision for q-expansion of modular forms used inside the code. Actually, >> this error happens when I ran Bosman's code and sage indicates that >> HeilbronnMere went wrong in this case. >> >> >> >> On Wednesday, February 27, 2013 2:26:55 PM UTC+1, John Cremona wrote: >>> >>> I cannot think of a reason for computing Heilbronn matrices of such >>> large index, so you have one? And how does it perform for smaller n, >>> say 1000, 10000, 20000, ...? >>> >>> Lastly, Sage-5.7 has been released so you should upgrade (but I am not >>> saying if any relevant code has changed between 5.4.1 and 5.7, as I >>> have not checked). >>> >>> John >>> >>> On 27 February 2013 11:32, Peng <tianpen...@gmail.com> wrote: >>> > Dear all, >>> > >>> > I've tried to compute Heilbronn Matrices for n=50000 in sage 5.4.1, but >>> > the >>> > following Error comes out when I run >>> > >>> > sage: H=HeilbronnMerel(50000) >>> > >>> > -------------------------------------------------------------------- >>> > >>> > RuntimeError Traceback (most recent call last) >>> > >>> > /home/guests/sage-5.4.1/<ipython console=""> in <module>() >>> > >>> > >>> > /home/guests/sage-5.4.1/local/lib/python2.7/site-packages/sage/modular/modsym/heilbronn.so >>> > in sage.modular.modsym.heilbronn.HeilbronnMerel.__init__ >>> > (sage/modular/modsym/heilbronn.c:5185)() >>> > >>> > >>> > /home/guests/sage-5.4.1/local/lib/python2.7/site-packages/sage/modular/modsym/heilbronn.so >>> > in sage.modular.modsym.heilbronn.HeilbronnMerel._initialize_list >>> > (sage/modular/modsym/heilbronn.c:5343)() >>> > >>> > RuntimeError: Floating point exception >>> > >>> > -------------------------------------------------------------------- >>> > >>> > It seems to be a bug in sage when computing Heilbronn Matrices for large >>> > n. >>> > However, I even couldn't find out why this happens. Anybody can please >>> > help >>> > me handle with that? Thank you. >>> > >>> > >>> > Best regards! >>> > >>> > -- >>> > You received this message because you are subscribed to the Google >>> > Groups >>> > "sage-devel" group. >>> > To unsubscribe from this group and stop receiving emails from it, send >>> > an >>> > email to sage-devel+...@googlegroups.com. >>> > To post to this group, send email to sage-...@googlegroups.com. >>> > Visit this group at http://groups.google.com/group/sage-devel?hl=en. >>> > For more options, visit https://groups.google.com/groups/opt_out. >>> > >>> > >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-devel" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sage-devel+unsubscr...@googlegroups.com. >> To post to this group, send email to sage-devel@googlegroups.com. >> Visit this group at http://groups.google.com/group/sage-devel?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
