[SCIP] branch-and-price-and-cut

[Horváth Markó]

Dear all,

none of my attempts were succesful. I have two further questions.

1) Is it possible to add new rows to the problem of the new child nodes 
during a branching? When using scip_execlp, I could add (stick) new 
constraints to the child nodes, but I cannot find similar functionality 
for new rows.

2) Assume I added new constraints to the child nodes during branching. 
When a node is focused, is it possible to add new rows to the problem 
(based on these constraints) before the first LP is solved? I tried to 
modify the LP inside callback scip_active, however, nothing happened.

Best regards,
Marko

2022. 06. 13. 9:42 keltezéssel, Horváth Markó írta:
> Dear all,
>
> I'm working on a branch-and-price-and-cut approach. Actually, it is a 
> branch-and-price approach, where until now, branching decisions were 
> handled by variable fixing (i.e., variables were fixed by the 
> propagation callback of the corresponding constraint handler). 
> However, I want to improve this branching, that is, in each child node 
> I want to add multiple rows to the problem. Of course, I need to store 
> these decisions to take them into consideration during variable 
> pricing. (So, yet it is a branch-and-price-and-cut approach, but cuts 
> are not added by separation procedure, but branching). I would like to 
> ask, what is the best way to do that? (My best guess, is that in a 
> branching rule I add the rows to the problem, and I also create a 
> constraint sticked to child nodes. The corresponding constraint 
> handler do nothing (may be propagation only), but could be used in 
> variable pricing).
>
> Thanks, and best regards,
> Marko
>
>
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-- 
Markó HORVÁTH PhD,
research fellow
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Research Laboratory on Engineering & Management Intelligence,
Institute for Computer Science and Control
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