> If the current basic solution is optimal and you free some previously > fixed variables, the solution cannot become primal infeasible; it may > become only non-optimal (dual infeasible). Or I misunderstand > something?
In my experience the solution becomes primal infeasible. Let's think to an extreme case: if you fix all the variables to their optimal value, all the columns will have the basis status GLP_NS (non-basic fixed variable). But when you free all the variables, the columns will stay out of basis: the basis status will be updated to GLP_NF, or GLP_NU, or GLP_NL depending on the new bounds. In my case, I set only the lower bound to 0, so that in the current solution all the variables have 0 as value (status GLP_NL), which corresponds to a primal infeasible solution. I'm wrong? Davide Anghinolfi _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
