Yes, I delete Rows and Cols For Row, must I use glp_set_row_stat(lp , i , GLP_NL)?
For Column, must I use glp_set_col_stat(lp , i , GLP_NL)? How can I fix my column at 0? must I resolve my problem before to add column or row? Or must I only start again the routine lpx_std_basis(lp)? Andrew Makhorin wrote: > >> I tested my example of column generation without the routine >> lpx_std_basis > >> Now, the result is good: > >> 0: objval = 0.000000000e+00 infeas = 1.000000000e+00 (0) >> 15: objval = 3.497400000e+04 infeas = 0.000000000e+00 (0) >> * 15: objval = 3.497400000e+04 infeas = 0.000000000e+00 (0) >> * 29: objval = 2.652371454e+02 infeas = 0.000000000e+00 (0) >> OPTIMAL SOLUTION FOUND >> * 29: objval = 2.652371454e+02 infeas = 0.000000000e+00 (0) >> * 31: objval = 6.586143114e+01 infeas = 0.000000000e+00 (0) >> OPTIMAL SOLUTION FOUND > >> But, At the 55 st problem, I obtain: > >> spx_simplex: initial basis is invalid > >> Why? Normally, the precedent solution is feasible > >> I don't understand spx_simplex because I don't use. How do I repear >> the problem? when the lpx_simplex is different of LPX_E_OK > > If before changing the problem instance the basis was optimal, you > do not need to repair it. Probably you changed the status of some > rows/columns, or deleted some active rows and/or basic columns; this > invalidates the basis. If you need to delete an active row, just make > it free; similarly, to delete a basic column it is sufficient to fix > it at zero. > > > > _______________________________________________ > Help-glpk mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/help-glpk > > -- View this message in context: http://www.nabble.com/Problem-%3A-basis-tf3882882.html#a11008669 Sent from the Gnu - GLPK - Help mailing list archive at Nabble.com. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
