Dear Mike and kcrisman, Thank you for providing me with some pointers!
On 15 Feb., 17:29, kcrisman <kcris...@gmail.com> wrote: > ... > So it is using the Ginac gcd, and calling it 'g_gcd'. And all of that > is in a call > > cdef extern from "ginac_wrap.h": > > which lives in devel/sage/c_lib/include. I understand nearly > nothing about headers, but I think that > > py_funcs_struct py_funcs "GiNaC::py_funcs" > > means that py_gcd is going to be under this. Notice that Pynac > headers live in $SAGE_ROOT/local/include/pynac. In other words: * sage.rings.arith.gcd(a,b) calls a.gcd(b) * a.gcd(b) calls g_gcd(a._gobj,b._gobj). * g_gcd calls py_gcd for the objects that are underlying a and b; call these objects A and B * py_gcd(A,B) returns sage.rings.arith.gcd(A,B). Since (probably) A is an integer and B is rational, it is indeed a case that has changed with my patch. However, I can not understand yet why the minus sign is not pulled out of (-sqrt(2)-1/5*I)^2. Neither do I understand why (1/ sqrt(2*pi*1^2)*exp(-1/(2*1^2)*(x-0)^2) - 1/sqrt(2*pi*n(1)^2)*exp(-1/ (2*n(1)^2)*(x-n(0))^2))^2 segfaults. > I don't know if we want to modify Ginac to change this, though. I think a segfault caused by a different choice of a gcd is nasty and probably a bug. But I guess Ginac is beyond my understanding. Best regards, Simon -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
