Martin Rubey wrote: > > I'd be very grateful if somebody could look at the input file below. (Don't be > afraid, most of the definitions are not needed) > > I would have thought that bug() would yield twice the same thing. It may be a > mistake on my side, of course, but note that > > * axiom does not compute > > map(c +-> sqrtrule c, series(first Phi Psi Phi [x,y,Z.2], t=0)::ULS(EXPR > INT, t, 0)) >
Using FriCAS I get errors. I would prefer clearer error message, but as William Sit noted, this can not really work due to zero denominators. > * neither axiom nor fricas can compute > > map(c +-> sqrtrule c, series(first Phi Psi Phi [x,y,Z.2], t=0)::ULS(EXPR > INT, t, 0))-first Phi Psi Phi [x,y,Z2] > > > since this is actual work, I'd be extremely grateful for help! > > Martin > > ------------------------------------------------------------------------------- > K := ((t*y+t*x)*z*z+(t*y*y+(-x*y)+t*x*x)*z+t*x*y*y+t*x*x*y) > Z := zerosOf(K, z) > > sqrtrule := rule sqrt(a^2*?b) == a*sqrt b > Z1 := map(c +-> sqrtrule c, series(Z.1, t=0)::ULS(EXPR INT, t, 0))::ULS(FRAC > POLY INT, t, 0) > Z2 := map(c +-> sqrtrule c, series(Z.2, t=0)::ULS(EXPR INT, t, 0))::ULS(FRAC > POLY INT, t, 0) > > Phi l == [l.2 * l.3/ l.1, l.2, l.3] > > Psi l == [l.1, l.1 * l.3/l.2, l.3] > > -- I guess the following is a bug: > -- I cannot even subtract the two! > bug() == > output map(c +-> sqrtrule c, series(first Phi Psi Phi [x,y,Z.2], > t=0)::ULS(EXPR INT, t, 0)) > output first Phi Psi Phi [x,y,Z2] > You may consider alternative way of doing computation: sd := x*y*sqrt(argument (kernels(numer(Z.1)::Expression Integer + t*y^2_ -x*y + t*x^2).1).1/(x^2*y^2)) ZZ1 := (sd - (t*y^2 -x*y + t*x^2))/(2*t*(x+y)) ZZ2 := (-sd - (t*y^2 -x*y + t*x^2))/(2*t*(x+y)) then series(first Phi Psi Phi [x,y,ZZ2], t=0)::ULS(EXPR INT, t, 0)_ - first Phi Psi Phi [x,y,Z2] gives me 0. -- Waldek Hebisch [EMAIL PROTECTED] _______________________________________________ Axiom-developer mailing list Axiom-developer@nongnu.org http://lists.nongnu.org/mailman/listinfo/axiom-developer