Re: [Help-glpk] is it possible to determine the value a nb variable will take?

[Michael Hennebry]

On Mon, 29 Dec 2008, Selçuk Cihan wrote:

> > It calculates amounts by which variable bounds may be changed in the
> > original problem while the optimal basis remains the same.
>
> i am working with suboptimal solutions, lpx_print_sens_bnds() is of no
> use for me i guess, it just tells me that i do not have an optimal
> solution.

I think that GLPK has a mechanism for getting a column of the simplex tableau.
That should add enough information to get you what you want.

> i am not sure if i made myself clear, due most probably to my lack of
> experience in linear programming. what i need is, to be able to
> implement my own iterative algorithm, for solving a 0-1 integer
> program. The iterations will start from the optimal solution of the LP
> relaxation of the 0-1 integer program. At each iteration i will select
> a nonbasic variable and make it enter to the basis. That is called a
> move.

If you get it working at all, I'd like to see it.
I have some integer programming ideas that would also
require thorough control over the simplex method.
With GLPK, I have usually used the API because
LP was part of a larger algorithm.
The larger algorithm did not require tinkering with the internals of LP.

--
Michael   address@hidden
"Pessimist: The glass is half empty.
Optimist:   The glass is half full.
Engineer:   The glass is twice as big as it needs to be."