> Trying to debug a stack error in GLPK, I am writing the problem out at > every iteration of a column generation scheme > Initially only in the free mps format, but then also in the lp format > One major and one minor error occur: > major: write_freemps does not write the objective function coefficients,
This is not a bug. If the instance has at least one free (unbounded) row, by default lpx_write_mps does not write the objective row assuming that that free row is the objective row. In order to tell lpx_write_mps to write the objective row in any case you should change the control parameter LPX_K_MPSOBJ as follows: lpx_set_int_parm(lp, LPX_K_MPSOBJ, 1); For more details please see the glpk reference manual. > no column has a non-zero in the objective function > minor: write_cpxlp creates one extra variable in the bounds section that > does not appear anywhere else in the problem statement That variable exists in the problem object, however, its column is empty (as seen in mps file). _______________________________________________ Bug-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-glpk
