-------- Forwarded Message -------- From: Will Tipton <[email protected]> To: [email protected] Cc: John Rice <[email protected]> Subject: identifying infeasible problem without using the LP presolver Date: Mon, 21 Mar 2022 11:15:44 -0400
> Hi help-glpk, > > We're using GLPK's simplex algorithm to solve some medium-sized lp > problems (hundreds of variables and constraints). We've found that the > presolver produces bad solutions, and we suspect that it's due to > numerical issues, since the constraints may be near-degenerate in many > cases. > > Running without the presolver usually works great. However, we can't > rely on the results in this case, because the simplex algorithm > returns an OK error code even when it fails to find a feasible > solution. > > So: > How hard would it be to get errors in case there is no feasible > solution when not using the presolver? > Any tips on debugging presolver stability problems? > Thanks in advance, > Will
