[Scip] New Solution Callback

[Stefan Heinz]

Hi,

I attached an event handler which checks for "best solution found". This one 
can be easily changed to "solution found" (Just replace 
SCIP_EVENTTYPE_BESTSOLFOUND with SCIP_EVENTTYPE_SOLFOUND).

The only thing you have to do, is to initialize the even handler before you 
call SCIPsolve() with the call
SCIP_CALL( SCIPcreateEventHdlrBestsol(scip) );

The event handler is written in C which should be no problem with your C++ 
project. You can also transform the C files into C++ file.

Hope that helps 
Stefan




Am Freitag 16 Juli 2010 22:28:19 schrieb Jakob Breier:
> Hi,
> 
> I am a student from the RWTH Aachen and I am working on a project using
> scip. I am working with the C++ Interface and I want to write out the
> currently best solutions every time a new solution is found, because the
> process crashes quite often (out of memory, system reboot, etc.). I
> believe the SOLFOUND event is the proper event to use (?). Unfortunately
> the following code does not work:
> =============SolFoundEventHandler.h=============
> #include "scip/scip.h"
> #include "objscip/objeventhdlr.h"
> 
> 
> class SolFoundEventHandler : public scip::ObjEventhdlr
> {
> 
>          private:
> 
>          public:
>                  SolFoundEventHandler();
>                  virtual SCIP_RETCODE scip_exec(
>                                       SCIP*              scip,
>                                       SCIP_EVENTHDLR*    eventhdlr,
>                                       SCIP_EVENT*        event,
>                                       SCIP_EVENTDATA*    eventdata
>                                       ) ;
> 
> 
> };
> 
> ============SolFoundEventHandler.cpp============
> #include "SolFoundEventHandler.h"
> 
> 
> SolFoundEventHandler::SolFoundEventHandler() :
> ObjEventhdlr("SOLFOUND","desc")
> // As far as I understand the interface the above line should tell
> // scip that I want to catch the SOLFOUND event.
> {
> 
> }
> 
> 
> SCIP_RETCODE SolFoundEventHandler::scip_exec(
>          SCIP*              scip,
>          SCIP_EVENTHDLR*    eventhdlr,
>          SCIP_EVENT*        event,
>          SCIP_EVENTDATA*    eventdata
>          )
> {
> 
>          SCIPerrorMessage("This message will never be printed.");
>          SCIPABORT();
> 
>          return SCIP_OKAY;
> 
> 
> }
> 
> Also "SCIP_CALL_ABORT(SCIPincludeObjEventhdlr(scip_,
> &solFoundEventHandler, false));" is called before the solving begins
> (solFoundEventHandler is of course an object of type
> SolFoundEventHandler). Yet SCIP_RETCODE SolFoundEventHandler::scip_exec
> is never called.
> Do you know what I do wrong?
> 
> Regards,
> Jakob Breier
> _______________________________________________
> Scip mailing list
> Scip at zib.de
> http://listserv.zib.de/mailman/listinfo/scip
> 
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