On Monday, November 23, 2015 at 11:20:23 AM UTC-8, Dima Pasechnik wrote: > > the bug is not really in maxima, it's in Sage's interface to maxima: > > (%i7) limit(2/5*((3/4)^m - 1)*(a0 - 1000000) + 1/5*(3*(3/4)^m + > 2)*a0,m,inf); > (%o7) 400000 > > The stack overflow does happen in maxima, as you can see from the error messages that are printed upon failure in sage (the leading ";" gives a very lispy taste)
Indeed, if you execute domain: complex; limit(2/5*((3/4)^m - 1)*(a0 - 1000000) + 1/5*(3*(3/4)^m + 2)*a0,m,inf); things go haywire. Indeed, it's not hard to see how this limit might be problematic when viewed in terms of multi-valued complex functions. Maxima/SBCL fails a little less harshly, but still fails on a lisp error. I'm not sure if with "domain: complex" (which sage uses in maxima) this limit makes sense, but the way maxima fails is definitely a reportable bug in maxima. > (this is with 'sage --maxima') > probably extra maxima packages loaded along with maxima cause this OOM in > Sage. > > > >> >> Public worksheet: >> >> >> https://cloud.sagemath.com/projects/4a5f0542-5873-4eed-a85c-a18c706e8bcd/files/support/2015-11-22-163829-limit.sagews >> >> >> On Sun, Nov 22, 2015 at 2:00 PM, David Joyner <wdjo...@gmail.com> wrote: >> > Forwarded to the correct list >> > >> > ---------- Forwarded message ---------- >> > From: G. M.-S. <list...@gmail.com> >> > Date: Sun, Nov 22, 2015 at 4:34 PM >> > Subject: [sage-release] Bug in limit? >> > To: sage-r...@googlegroups.com >> > >> > >> > >> > Hello. >> > >> > This is my first post, please be indulgent. >> > >> > Is the following a bug? >> > >> > Thanks in advance. >> > >> > Guillermo Moreno-Socías >> > >> > ┌────────────────────────────────────────────────────────────────────┐ >> > │ SageMath Version 6.9, Release Date: 2015-10-10 │ >> > │ Type "notebook()" for the browser-based notebook interface. │ >> > │ Type "help()" for help. │ >> > └────────────────────────────────────────────────────────────────────┘ >> > sage: var('m a0') >> > (m, a0) >> > sage: x=2/5*((3/4)^m - 1)*(a0 - 1000000) + 1/5*(3*(3/4)^m + 2)*a0;x >> > 2/5*((3/4)^m - 1)*(a0 - 1000000) + 1/5*(3*(3/4)^m + 2)*a0 >> > sage: limit(x,m=oo) >> > >> > ;;; >> > ;;; Detected access to protected memory, also kwown as 'bus or >> > segmentation fault'. >> > ;;; Jumping to the outermost toplevel prompt >> > ;;; >> > >> > (Note that if x is expanded then the limit is correctly calculated.) >> > >> > -- >> > You received this message because you are subscribed to the Google >> > Groups "sage-release" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> > an email to sage-release...@googlegroups.com. >> > To post to this group, send email to sage-r...@googlegroups.com. >> > Visit this group at http://groups.google.com/group/sage-release. >> > For more options, visit https://groups.google.com/d/optout. >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups "sage-support" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an email to sage-support...@googlegroups.com. >> > To post to this group, send email to sage-s...@googlegroups.com. >> > Visit this group at http://groups.google.com/group/sage-support. >> > For more options, visit https://groups.google.com/d/optout. >> >> >> >> -- >> William (http://wstein.org) >> > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
