[Scip] Solving a subproblem within a B&B node

[Ambros Gleixner]

Dear Andrei,

You are correct that changes in the sub-SCIP do not affect anything but 
the sub-SCIP.  Happy coding,

Ambros


Am 04.04.2015 um 03:41 schrieb Andrei Braga:
>    Hello again,
>
>    Reading the source code of SCIPcopy() method, I understood that it
> creates a
> new and independent SCIP instance, and copies into this instance information
> from the original one. Then, I concluded that my concern about changes in a
> sub-scip affecting the original SCIP instance makes no sense.
>
>    I will keep going with my implementation, and report on further issues.
>
>    Best regards,
>
>
> On Fri, Apr 3, 2015 at 11:41 AM, Andrei Braga <andreisampaio at gmail.com
> <mailto:andreisampaio at gmail.com>> wrote:
>
>        Dear all,
>
>        I am new to SCIP and I am trying to code a branch-and-price
>     method. I'd like
>     to ask you about how to implement the steps I describe below.
>
>        I've read about "diving" and "probing", but I think these aren't
>     approaches
>     suited for my purposes. I guess I should use a "sub-SCIP" (which I
>     suppose is
>     obtained through a call to the scipCopy() method), but I don't
>     understand the
>     details of the process (for example, changes made in the sub-SCIP
>     affect the
>     original SCIP instance?).
>
>        Let X be a subset of variables. When, after LP solving in a B&B
>     node, all
>     variables in X have integer value, I want to:
>        1) Create an copy of SCIP;
>        2) In this copy, delete some variables and constraints;
>        3) In this copy, replace the branching rules and the pricers by
>     other ones;
>        4) In this copy, solve the "smaller" problem to optimality;
>        5) In the original SCIP instance, prune the B&B-node for optimality.
>     I need that the deletions made in the SCIP copy do not affect the
>     original
>     SCIP instance.
>
>        Thank you very much,
>
>     --
>     Andrei Braga
>
>
>
>
> --
> Andrei Braga
>
>
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-- 
______________________________________________________________
Ambros M. Gleixner
Zuse Institute Berlin - TU Berlin - Berlin Mathematical School
http://www.zib.de/gleixner