Hi Alex! On 30 Dez., 06:37, Alex P <alexvpetr...@gmail.com> wrote: > Here is the code: > > ---------------------------------------------------------------------- > | Sage Version 4.2.1, Release Date: 2009-11-14 | > | Type notebook() for the GUI, and license() for information. | > ---------------------------------------------------------------------- > sage: q = 3 > sage: F.<a> = FiniteField(q) > sage: P.<T> = PolynomialRing(F) > sage: PP.<z> = PolynomialRing(P) [...] > sage: time (z^3 + T*z)^(3^7) > ^CException KeyboardInterrupt: KeyboardInterrupt() in > 'sage.rings.polynomial.polynomial_zmod_flint.get_cparent' ignored > ^C > > ------------------------------------------------------------ > Unhandled SIGFPE: An unhandled floating point exception occured in > SAGE. > This probably occured because a *compiled* component > of SAGE has a bug in it (typically accessing invalid memory) > or is not properly wrapped with _sig_on, _sig_off. > You might want to run SAGE under gdb with 'sage -gdb' to debug this. > SAGE will now terminate (sorry). > ------------------------------------------------------------
That's certainly a bug. I created a ticket for it: http://trac.sagemath.org/sage_trac/ticket/7794 As it is defined, PP is a polynomial ring in one variable over a polynomial ring in one variable. Would it be a good thing to automatically convert this into a polynomial ring with *two* variables? What do people think? If you have an opinion about it, you might also comment on http://trac.sagemath.org/sage_trac/ticket/7580, where I do those conversions for Infinite Polynomial Rings. Note that Alex' example reveals another bug, this time in MPolynomialRing_libsingular: sage: F.<a> = FiniteField(3) sage: P.<T,z> = PolynomialRing(F) sage: type(P) <type 'sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular'> sage: (z^3 + T*z)^(81*3) # immediate answer z^729 + T^243*z^243 sage: (z^3 + T*z)^(2^20) /home/king/SAGE/sage-4.3/local/bin/sage-sage: line 206: 20889 Segmentation fault sage-ipython "$@" -i This was without Ctrl-C. Certainly there should be no segfault. If anything, there should an error be raised. I made this another ticket, http://trac.sagemath.org/sage_trac/ticket/7795 Thanks for the report! Simon -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
