Helloooooooooooooooooo !!!! > Hi Nathann, > does your code provide for returning infeasibility certificates? > in case of CPLEX Python interface, it's here: > <lp-problem>.solution.advanced.dual_farkas()
Certificates ? No, it raises exceptions for the moment, which can give you some idea of why it failed depending on the solver, but which kind of certificate can you return for a MILP ? The only one I can think about is the whole tree :-) I'll give this method a look. But actually, if we can peacefully deal with the C interface, there's no reason why we shouldn't be able to do it. I mean, assuming they exposed everything in C before exposing it in Python ! > This is something I need for our research on quantum codes; I have an > industrial > amount of smallish LPs, most of them infeasible, and have to > understand why... > I started out using Sage/cvxopt interface to GLPK, and then switched > to CPLEX, > as I wanted these certificates, as well as ILP solutions, when they > exist. Nice to know ! > By the way, CPLEX Python interface does allow cut generation from > within Python, so claiming that Sage is the 1st do do this is a bit > too strong... It is not when you have ignorance on your side :-D Well, everybody I ever met who was dealing with constraint generation was doing it in C, the code being ages away from the original LP formulation... Sorry for that :-) Nathann -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
