[Coin-discuss] Retrieving branching information

[Laszlo Ladanyi]

Hi Thomas,

I'm not sure if anybody has replied to your question, so here it is:

You are right, the initialize_new_search_tree_node method is the place to
extract the former branching decisions. Both for variables and cuts there is
method: is_non_removable() which gets set iff the object has been
branched on (bad naming, I know...). So just scan through the vars/cuts and
record the former branching decisions in a member variable of your class
derived from BCP_lp_user.

Let me know if this info is sufficient.

-Laci

On Tue, 9 Sep 2003, Thomas K. Stidsen wrote:

> Hi
> 
> I am currently trying to implement a Branch and Price algorithm
> in BCP, using Ryan-Foster branching, i.e. branching on an added
> constraint. The branching part seems to work but I have a problem:
> Retrieving the branching information, because I need to take the
> previous branching decisions into account when solving the subproblem.
> So the question is: How do I store this information in the "children"
> before actually branching (probably in the method
> " select_branching_candidates 
> <http://www-124.ibm.com/developerworks/opensource/coin/Doxygen/Bcp/class_b_c_p__lp__user.html#z202_0> 
> ()" ) and how do I retrieve this information
> again (probably in the method  " initialize_new_search_tree_node 
> <http://www-124.ibm.com/developerworks/opensource/coin/Doxygen/Bcp/class_b_c_p__lp__user.html#a1> 
> ()" ) ?
> The actual branching involves adding a constraint with either 0 or one on
> the righthandside. The lefthandsides are identical, but I need to be able
> to get the value of the righthandsides and get the information on how the
> lefthandsides were generated.
> 
> Best Regards Thomas Stidsen
> 
> -- 
> Thomas Stidsen                       Assistant Professor
> Email:                               Email: thomas at stidsen.dk
> Phone:                               Tlf. : (+45) 45 25 33 84
> IMM, Technical University of Denmark
> 
> 
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