[Scip] How to solve the root LP associated to an MIP

[Stefan Heinz]

Hi Matrin,

You could set the node limit to 1 and call SCIPsolve(). This will start SCIP 
as usual (including presolving and propagation) and stops after the root node 
is solved (including the LP).

Hope that helps
Stefan

On Monday 15 March 2010 10:21:19 Martin Bergner wrote:
> Hello all,
> 
> I want to solve the LP associated to a given MIP before actually solving
> the MIP (e.g. before calling SCIPsolve()). I suspected that I could call
> constructLP and then solve that somehow. Unfortunately, I coud not
> construct the LP both in the presolving and transforming stage.
> 
> What I did now, is that in a relaxation handler exec method I call
> SCIPconstructLP / SCIPstartProbing / SCIPsolveProbingLP /
> SCIPendProbing. I can access the dual variables associated to MIP
> constraints, which works somehow.
> 
> However, I actually only want to solve the root LP of my main MIP and
> then the (root) LPs associated to my subproblems. My current approach
> would force me to implement a relaxator for the subproblems only to
> construct the root LP, which seems to be quite awkward.
> 
> So what is the canonical way to construct and solve the root LP of an
> MIP before actually starting the branch and cut algorithm?
> 
> Unfortunately, I didn't find any suitable LP method in scip.h and
> pub_lp.h that seem to to what I want.
> 
> Regards and thanks
> Martin
> 
> P.S.: I'm currently using scip 1.2.0.8.
> 
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