[Help-glpk] Re: branch-and-cut

[Andrew Makhorin]

>My application was implemented in a similar way
>(tspsol), but I don`t want that constraints are
>deleted from the workspace when the subproblem has
>been deleted. I wish that to each time that a
>relaxation will be solved, I can  remove unnecessary
>constraints, for example, the contraints with large
>slack. My cutting planes are not very effective, the
>LP's enlarge and it consumes more time, although the
>number of visited nodes diminishes.

glpbcs allows only locally valid constraints, so it is impossible to
keep a constraint in the workspace after the corresponding subproblem
has been removed from the tree.

You can either regenerate necessary constraints or, if the generating
algorithm is expensive, keep them somewhere apart using your own data
structures (for example, in the same format as used in bcs_add_con).
Unfortunately, glpbcs does not support constraint pools.