On Mon, Jun 5, 2023 at 8:19 PM Brent W. Baccala <cos...@freesoft.org> wrote: > > Hi - > > I don't think giac can handle more than 15 variables in a Gröbner basis > calculation. > > This limitation isn't really documented anywhere, but if you look in giac's > src/cocoa.cc around lines 490-500, function swap_indices and think about it a > few minutes, you'll see that it can't handle more than 15 variables, I think. > I'm looking at giac 1.9.0. > > I tried a calculation on a ring with 67 variables and the algorithm went into > an infinite loop because it couldn't compare monomial exponents properly. It > produced a polynomial with two terms, both with the same monomial (different > coefficients), and that triggered the infinite loop in the reduction code. > > I hope somebody working with this code will check my work and verify that > giac is so limited. If so, we should add a check to the groebner_basis > routine in src/sage/libs/giac/__init__.py
Thanks. Filed as https://github.com/sagemath/sage/issues/35744 Best, Dima > > agape > brent > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/83301b12-14ff-44e1-a0f6-33021050161bn%40googlegroups.com. -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq2qitO_DkwXQ6YW348DZ-Qkiu749PNaBimF5FAN0rqUyQ%40mail.gmail.com.
