This was a "demonstration problem" - my actual application will involve arbitrary-precision reals with lots of constraints.
It appears that PPL not only supports rationals, but insists on them. It seems to set the base_ring to QQ, as the output from the following code is "Rational Field", but I can find no way to alter base_ring. Any suggestions on how I might accomplish that? (For glpk the base_ring is "Real Double Field", and I can't find a way to alter that either.) from sage.numerical.backends.generic_backend import get_solver p = get_solver(solver = "PPL") print p.base_ring() On Thursday, October 23, 2014 5:06:14 PM UTC-4, Volker Braun wrote: > > If your problem is over QQ then just use that (PPL supports exact > rationals). > > On Thursday, October 23, 2014 4:38:39 AM UTC+1, Mike wrote: >> >> I'd like to be able to do linear programming to arbitrary precision. The >> documentation that I've found claims that both the glpk and PPL solvers >> should do this, but I haven't been able to get either to work. >> >> As an example, the following code prints c to high precision, but the >> solutions only to 12 digits. Where should I look for guidance? >> Note: this seeks to maximize x+y given that 3x<=1 and 3y<=1, so the >> solution is (1/3, 1/3) >> >> Mike M >> >> R=RealField(100) >> c=Matrix(R, 2, 1, [-1, -1]) >> G=Matrix(R, 2, 2, [3, 0, 0, 3]) >> h=Matrix(R, 2, 1, [1, 1]) >> print c # To check the precision being used by "print" >> print >> >> sol=linear_program(c,G,h) >> print sol['x'] >> sol=linear_program(c,G,h, solver='glpk') >> print sol['x'] >> sol=linear_program(c,G,h, solver='PPL') >> print sol['x'] >> >> -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
