If BPMPD_MEX is called via qps_matpower, as it is when running a DC OPF in MATPOWER, then the solution is checked for feasibility. If the solution fails the feasibility check, then the WARNING is printed and the problem is re-solved using MIPS.
So, your results should be correct, it's just that the problem was solved twice, the first time quickly but incorrectly by BPMPD and the second time correctly, but probably more slowly by MIPS. -- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jun 1, 2011, at 6:00 PM, <[email protected]> <[email protected]> wrote: > I have forgot that I have a warning with BPMPD_MEX, when the line cost is > cero, i.e., for a system with three nodes, the cost matrix is: > > Line 1: (-20 0 -40 0 -60 0 0 0 20 0 40 0 60 0) > Line 1: (-20 60 -40 120 -60 200 0 0 20 50 40 100 60 150) > Line 1: (-20 0 -40 0 -60 0 0 0 20 0 40 0 60 0) > > WARNING: This version of BPMPD_MEX has a bug which caused it to return > an incorrect (infeasible) solution for this particular problem. > equality constraint violated by 1 > > But the responses are correct. Could I have other problems? > > Thank you very much for your attention > > > ---------------------------- Mensaje original ---------------------------- > Asunto: RE: Question > De: [email protected] > Fecha: Mie, 1 de Junio de 2011, 4:35 pm > Para: [email protected] > -------------------------------------------------------------------------- > > Thank Professor Zimmerman for your idea. > > I have resolved this problem with another idea. I created a two variables: > Flow in the line (F) and a auxiliary for piecewise linear cost (z). The F > variable has limits negatives, i.e., -Fmin<=F<=+Fmax and besides F can > have any direction. On the other hand the z variable can have only cost > positive for any flow direction, i.e. line costs are ordered as follows: > (-20 60 -40 120 -60 200 0 0 20 50 40 100 60 150) > > Bloqs From 1 To 2 (Capacity=45MW) > 20 MW 50 $ > 40 MW 100 $ > 60 MW 150 $ > > Bloqs From 1 To 2 (Capacity=45MW) > -20 MW 60 $ > -40 MW 120 $ > -60 MW 200 $ > > What is your opinion about my idea?. So far the idea works very well, but > I am not sure about the convergence the problem, when there are a lot of > cost. > > Best Regards, > Santiago Chamba > > > >
