[Help-glpk] How to solve a dual problem

[David Pérez]

We are using Glpk branch-and-cut for solving a bilevel problem. In order to 
generate new cuts we need to solve a dual problem associated to one lp problem. 
Is there any way to generate the cols and rows of the dual problem?. We think 
that the objective function optimization value will be the same when the 
problem has a feasible and bounded solution.

We´ve tryed the glp_get_row_dual and glp_get_col_dual
but the number of rows and cols doesn´t seem to correspond to the dual problem.
 
We´ve tryed to change the simplex method to GLP_DUAL but the above methods 
doesn´t return the correct number items of the associated dual problem.

Thanks in advance. David.