On Tue, 16 Feb 2010 12:41:31 William Stein wrote: > On Mon, Feb 15, 2010 at 3:09 PM, François Bissey > > <f.r.bis...@massey.ac.nz> wrote: > > On Tue, 16 Feb 2010 10:40:11 William Stein wrote: > >> > sage -t "devel/sage/doc/en/tutorial/tour_numtheory.rst" > >> > ********************************************************************** > >> > File "/opt/sage/devel/sage/doc/en/tutorial/tour_numtheory.rst", line > >> > 94: sage: x = crt(2, 1, 3, 5); x > >> > Expected: > >> > -4 > >> > Got: > >> > 11 > >> > >> The above two are because you are using GMP instead of MPIR. > > > > So you are saying we need to link against the mpir version of the gmp > > libraries and that linking against gmp ones produces this result. > > If you link against mpir then the above discrepancy would go away. > However, i can also tell you that the above discrepancy is harmless. > The issue is simply that both answers are right. e.g., the line > > sage: x = crt(2, 1, 3, 5); x > > uses the Chinese Remainder Theorem to find an integer x such that x % > 3 == 2 and x%5 == 1. Both -4 and 11 are correct choices of x. > The other related tests involving "modular symbols" are different > because of the same function. >
I thought it was the case, and I remember patching xgcd in gmp for sage-3.0, I guess gmp hasn't step up that one yet, at least in the gmp-4 releases. May be it is in for gmp-5, we could force it if that solved the problem. > > I guess a finer point to know is. is this result correct but not reduce > > to same domain? And does it have nasty consequences later - ie do > > other thing rely on the result to be in this domain? > > No, there is definitely no nasty consequence. > Good. > > One more question, if we need to link against mpir's libgmp, does linking > > sage itself against it enough, or do we need to also link pari, mpfr, > > mpfi and other against it as well? mpfr in itself would be a problem as > > it is part of the toolchain (gcc is compiled against it). > > I think linking sage itself is likely to be enough for doctests to > pass, though it is hard to be sure. It would be nice to link pari > too. > I may have a strategy to use mpir instead of gmp in pari and some others if needed although mpfr would need extra care if required. Francois -- 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
