Note that for triangulating, sage does not help sage: M.polyhedron().triangulate() Traceback (most recent call last): ... NotImplementedError: triangulation of non-compact polyhedra that are not cones is not supported
On Wed, 21 May 2025 at 18:39, Dima Pasechnik <dimp...@gmail.com> wrote: > > PS. You also have not set an objective function, not sure, but it could be > why you have no termination > > On Wed, May 21, 2025, 11:37 Dima Pasechnik <dimp...@gmail.com> wrote: >> >> It should be possible to construct the polyhedron determined by the feasible >> set of the LP, triangulate it, and do simplex by simplex or perhaps use >> various results relating volumes and presence of integral points in >> polyhedra. >> >> On Wed, May 21, 2025, 11:27 Vincent Delecroix <20100.delecr...@gmail.com> >> wrote: >>> >>> Dear all, >>> >>> I have a 7 variables 3 constraints linear program that I want to solve >>> with integers >>> >>> x = M.new_variable(integer=True, nonnegative=True) >>> M.add_constraint(x[0] - x[1] + x[2] - x[3] - x[4] - 2 * x[6] == 2) >>> M.add_constraint(x[0] - x[1] + x[2] - 2 * x[4] - x[5] - x[6] == 2) >>> M.add_constraint(2 * x[0] - x[3] - x[4] - x[5] - x[6] == -1) >>> >>> However, with both >>> >>> M = MixedIntegerLinearProgram(solver="PPL") >>> >>> and >>> >>> M = MixedIntegerLinearProgram(solver="GLPK") >>> >>> The command M.solve() does not terminate in reasonable time... I do >>> not expect the system to have solutions, but I would like a proof of >>> it. >>> >>> One subtlety of the system is that there are (infinitely many) >>> positive integral solutions of the homogeneous version (ie linear >>> combination == 0). I wondered if that was the reason why it is harder >>> for a solver. >>> >>> If anyone knows of an alternative way to provide an open source >>> computer assisted proof that there is no solution I would be >>> interested. >>> >>> Best >>> Vincent >>> >>> -- >>> 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 view this discussion visit >>> https://groups.google.com/d/msgid/sage-support/CAGEwAAnr71Pi7151VHkQ0OCCYrXVhXgjc9zt5s5V3jezE%2BdUqQ%40mail.gmail.com. > > -- > 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 view this discussion visit > https://groups.google.com/d/msgid/sage-support/CAAWYfq2UvmPYJmuqHN5xRDctY2dHtOkr1k-3ymgEPw0Y1gz3Tw%40mail.gmail.com. -- 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 view this discussion visit https://groups.google.com/d/msgid/sage-support/CAGEwAAnnaXtQ8TarBkB2nd0Miw%3DsDOJUoJvW3pBpL_xc3_ENmA%40mail.gmail.com.
