[Scip] New Solution Callback

[Jakob Breier]

Hi Stefan,

thank you, this is a very helpful example. Up until now I wasn't sure, 
were to put the SCIPcatchEvent and SCIPdropEvent calls (I still don't 
understand why they belong in SCIP_DECL_EVENTINIT and 
SCIP_DECL_EVENTEXIT but I am happy to have the definite answer that they 
do).
If you don't mind, I would like to ask you to make your example public 
in the online documentation and put a link to it on the HOWTO-page ( 
http://scip.zib.de/doc/html/EVENT.html )

Regards,
Jakob Breier

On 07/18/2010 09:55 PM, Stefan Heinz wrote:
> 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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>>      

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