On Sat, Nov 10, 2018 at 12:02 PM Waldek Hebisch <hebi...@math.uni.wroc.pl> wrote: ... > > I have now implemented the lift part of Davenport-Caruso method. > You fetch code at: > > http://www.math.uni.wroc.pl/~hebisch/fricas/dcfact2.input > http://www.math.uni.wroc.pl/~hebisch/fricas/nc_ini04c.input > > As before, dcfact2.input is an actual routine, nc_ini04c.input > set up needed types. > > You can try things like: > > dc_fact(((x*z - z*x)^2 - 2)*((x*z - z*x)^2 - 3)*((x*z - z*x)^2 - 5)) > > The idea is like in Caruso preprint, but code differs -- I coded > what follows by working out solutions to lift equations. > > The code is unoptimized, for example for homogeneous polynomials > it runs the whole lift, while we know that the factorization must > be homogeneous... Also, code introduces extra parameters > when there is overlap between leading monomials of top factors, > while in many cases this parameter could be immediately eliminated. > Still, it seem to work quite a bit faster than xdpolyf1.spad. > > --
This looks very promising however I did find this apparent failure: (82) -> h3 (82) - z y x + z x y + y z x - y x z - x z y + x y z Type: XDistributedPolynomial(OrderedVariableList([x,y,z,w,x1,x2,x3,x4,x5]),Fraction(Integer)) Time: 0.00 (OT) = 0.00 sec (83) -> dc_fact((3+x*z*y)*h3) (83) [ - 3 z y x + 3 z x y + 3 y z x - 3 y x z - 3 x z y + 3 x y z - x z y z y x + 2 2 x z y z x y + x z y z x - x z y x z - x z y x z y + x z y x y z ] Type: List(XDistributedPolynomial(OrderedVariableList([x,y,z,w,x1,x2,x3,x4,x5]),Fraction(Integer))) Time: 0.00 (OT) = 0.00 sec -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to fricas-devel+unsubscr...@googlegroups.com. To post to this group, send email to fricas-devel@googlegroups.com. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.