[SCIP] Number of heuristic's calls

[Gregor Hendel]

Hi Andre,

Is the if-statement really the last thing in the execution callback? 
Then I am not surprised.

When we write a heuristic, we generally try to make it return as fast as 
possible if some necessary preconditions are not satisfied, as it is in 
your case.

I guess that you set the result pointer to

*result = SCIP_DIDNOTFIND

prior to your new if-statement?
If so, this will still increase the run counter by 1 for the statistics. 
The correct result stages should be

*result = SCIP_DIDNOTRUN

if( ... )
{
    return SCIP_OKAY;
}

// all conditions are satisfied, run the heuristic

*result = SCIP_DIDNOTFIND;

// ...

if( foundsol )
    *result = SCIP_SUCCESS;

Cheers,
Gregor


Am 11.05.2018 um 15:59 schrieb André Filipe Lanca Serrano:
> Hi Gregor,
>
> Thanks for the tips.
>
>> Most likely, SCIP decides to restart the solution process, such that 
>> effectively not only 1, but 2 root nodes are evaluated. -> Exactly!
>
> I already verified the logs and SCIP is actually restarted.
>
> I included a statement into the end of heurExec callback to return 
> immediately if SCIPheurGetNCalls(heur) > 0 like this:
>
>      /** execution method of primal heuristic */
>      static
>      SCIP_DECL_HEUREXEC(heurExecAtfmGA)
>      {  /*lint --e{715}*/
>
>         ...
>
>         /* only call heuristic once at the root */
>     if (SCIPgetDepth(scip) <= 0 && SCIPheurGetNCalls(heur) > 0)
>     {
>         return SCIP_OKAY;
>     }
>     return SCIP_OKAY;
>      }
>
> It still runs my heuristic twice at the root node... What am I doing 
> wrong here?
>
>
> Quoting Gregor Hendel <hendel at zib.de>:
>
>> Hi Andre,
>>
>> the properties look good for the purpose you describe, although I 
>> would suggest to use the letter 'M' to indicate a heuristic of that 
>> name :)
>>
>> Most likely, SCIP decides to restart the solution process, such that 
>> effectively not only 1, but 2 root nodes are evaluated. Can you 
>> verify whether SCIP actually restarted from some log file output?
>>
>> If you really want to run only once, you have to include a statement 
>> into the heurExec callback to return immediately if 
>> SCIPheurGetNCalls(heur) > 0.
>>
>> Hope this helps,
>> Gregor
>>
>> Am 09.05.2018 um 16:33 schrieb André Filipe Lanca Serrano:
>>> Hi to all,
>>>
>>> I created an heuristic and I would like to call it just once, in the 
>>> root node, as the first heuristic. I'm using the following 
>>> properties in my heuristic.
>>>
>>> #define HEUR_NAME             "myheuristic"
>>> #define HEUR_DESC             "My heuristic"
>>> #define HEUR_DISPCHAR         'g'
>>> #define HEUR_PRIORITY         99999999
>>> #define HEUR_FREQ             0
>>> #define HEUR_FREQOFS          0
>>> #define HEUR_MAXDEPTH         -1
>>> #define HEUR_TIMING           SCIP_HEURTIMING_BEFORENODE
>>> #define HEUR_USESSUBSCIP      FALSE
>>>
>>> After running my project I get two calls from my heuristic using the 
>>> method SCIPheurGetNCalls(heur). What am I doing wrong here? Am I 
>>> missing smth? I followed all the instructions on how to add primal 
>>> heuristics and I guess it's smth to do with the properties...
>>>
>>> Thank you in advance.
>>>
>>> Kind regards,
>>> André Serrano
>>>
>>> _______________________________________________
>>> Scip mailing list
>>> Scip at zib.de
>>> https://listserv.zib.de/mailman/listinfo/scip
>>
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>
>
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