[Scip] Binpacking example

[Aao Du]

Dear Flipe and Gerald,

Thanks for your response. I understand better now.
Also, the NEEDCONS flag worked, thanks.

Emily

On Thu, Mar 26, 2015 at 4:45 AM, Gerald Gamrath <gamrath at zib.de> wrote:

>  Dear Emily,
>
> I'm not sure I understood you correctly. Normally, your constraint handler
> should provide some method SCIPcreateConsMyspecialcons(), in which you
> create consdata etc. and call SCIPcreateCons().
>
> Anyway, I assume the full error message you get reads
> "cannot create constraint <name> of type [conshdlrname] - constraint
> handler does not need constraints"?
>
> In that case, just set the NEEDCONS flag to TRUE when creating your
> constraint handler.
>
> Best,
> Gerald
>
>
>
>
> On 26.03.2015 04:04, Aao Du wrote:
>
> Also, I have been struggling with this error, so I was hoping you can help
> me out there.
> In my branching rule, I am creating two branches and two consdatas and
> therefore two constraints for each node. But, I am getting error while
> calling SCIPcreatecons(scip, con, name, consdata, conshdlr,...). The error
> is :
> ERROR: can not create constraint of type conshdlr
> ERROR <-8> in function call
>
>  I have checked that consdata is created and the conshdlr is found before
> calling this function. I dont know what else can cause this.
> I would be thankful for your help.
>
>  Emily
>
> On Wed, Mar 25, 2015 at 12:49 PM, Aao Du <aaoduu at gmail.com> wrote:
>
>> Dear all,
>>
>>  I have just started using SCIP. I want to implement a B&P algorithm in
>> C++. I am looking at the Bin Packing example as template. As I think I will
>> need to have branching rule, pricer and a conshdlr as well.
>> I am, however, confused with some point and cant figure out how it works.
>> I was hoping I can get help here.
>>
>>  First, I cant find where in the example the master problem is being
>> solved, i.e. I dont see SCIPsolve(scip) anywhere in the code! I am totaly
>> lost about it. I was expecting to use it as in the VRP example after
>> creating scip and including pricer(and in this case branch rule and
>> conshdlr).
>>
>>  Second, in the master problem, all the variables are given as
>> binary(not continuous) and then we are trying to get the dual values of the
>> master problem, isnt this wrong? I cant get how this works.
>>
>>  Thanks in advance,
>>
>>  Emily
>>
>
>
>
> _______________________________________________
> Scip mailing listScip at zib.dehttp://listserv.zib.de/mailman/listinfo/scip
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.zib.de/pipermail/scip/attachments/20150329/eb47ff91/attachment.html>