[Scip] Early Branching issues

[Jose L Walteros]

Hi Stefan,

Thanks for your quick response,  I changed the code as you suggested (I am
also changing some other parameters and I guess I confused the TRUE
parameter as the way to do it, thanks for the clarification) but still no
additional cut are generated.

I am using now:

SCIP_CALL( SCIPsetSeparating(scip, SCIP_PARAMSETTING_AGGRESSIVE, TRUE) );

I also tried the default.

For this formulation all the constraints of the master problem are Set
Partitioning constraints defined as:

SCIP_CALL( SCIPcreateConsBasicSetpart(scip, &(conss[s][i]), name, 0, NULL)
);
SCIP_CALL( SCIPsetConsModifiable(scip, conss[s][i], TRUE) );


I know  that no separators are called because in the execution summary the
number of calls to all separators is zero.

Is there anything I am missing?

Thanks

-Jose






On Wed, Feb 6, 2013 at 5:53 PM, Stefan Heinz <heinz at zib.de> wrote:

> Hi Jose,
>
> It should be possible to turn on the separation. The bool parameter you
> changed from TRUE to FALSE has nothing to with turning on or off the "OFF"
> mode.
>
> http://scip.zib.de/doc/html/**scip_8h.shtml#**
> af91abf95639f1bf2022c11d13a032**b10<http://scip.zib.de/doc/html/scip_8h.shtml#af91abf95639f1bf2022c11d13a032b10>
>
> It does the parameter change "quite" or not. Meaning with or without an
> output via the message handler. You need to change the second parameter to
> one of the followings:
>
> * SCIP_PARAMSETTING_DEFAULT which are the default values of all separating
> parameters
>
> * SCIP_PARAMSETTING_FAST such that the time spend for separating is
> decreased
>
> * SCIP_PARAMSETTING_AGGRESSIVE such that the separating is done more
> aggregative
>
> * SCIP_PARAMSETTING_OFF which turn off all separating
>
> Probably you want to try SCIP_PARAMSETTING_DEFAULT first.
>
> Best Stefan
>
>
> On 02/06/2013 09:59 PM, Jose L Walteros wrote:
>
>> Hi all,
>>
>> I am solving a problem via Branch and Price. For one of my experiments, I
>> am interested in stopping the pricing at a certain point in the B&B tree
>> to
>> heuristically obtain a good solution. Since I am no longer pricing new
>> variables, I am wondering if it is possible to activate the separate
>> algorithms to add default SCIP cutting planes after no more columns are
>> generated.
>>
>> I tried to play with SCIP_CALL( SCIPsetSeparating(scip,
>> SCIP_PARAMSETTING_OFF, TRUE) ); changing it from TRUE to FALSE but I did
>> not get the expected beheavior.
>>
>> Tanks
>>
>> -Jose
>>
>>
>>
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>
>
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