[SCIP] Same row added multiple times

[Ambros Gleixner]

Dear Matheus,

You can write the current LP relaxation with integrality information 
using SCIPwriteMIP().

Maybe check again what is happening and then you can give us also more 
details:  Where do you generate the cuts (root/local nodes), with which 
flags do you add them exactly, and how big is the violation (efficacy, 
i.e., normalized by the 2 norm of the coefficient vector)?

Best,
Ambros


Am 16.08.21 um 01:40 schrieb Matheus Ota:
> Dear Scipers,
> 
> I've been implementing a branch-and-cut using SCIP, I already 
> implemented the constraint handler and I'm adding the violated rows 
> using "SCIPaddRow". I'm also setting forcecut = true, and thus, I would 
> suppose that, once a violated row is added, the same row should not be 
> added again. However, my program add the same row multiple times.
> 
> For example, in one instance it adds this row in the beginning:
> 196 <= +196<t_x_7,2> +196<t_x_7,3> +196<t_x_6,2> +196<t_x_6,3> 
> +196<t_x_5,2> +196<t_x_5,3> +196<t_x_4,2> +196<t_x_4,3> -196<t_x_3,2> 
> -196<t_x_3,4> -196<t_x_2,3> -196<t_x_2,4> +196<t_x_1,2> +196<t_x_1,3> 
> +1<t_y_163> +392 <= 1e+20
> 
> Then, after exploring some other solution, it adds the same row again:
> 196 <= +196<t_x_7,2> +196<t_x_7,3> +196<t_x_6,2> +196<t_x_6,3> 
> +196<t_x_5,2> +196<t_x_5,3> +196<t_x_4,2> +196<t_x_4,3> -196<t_x_3,2> 
> -196<t_x_3,4> -196<t_x_2,3> -196<t_x_2,4> +196<t_x_1,2> +196<t_x_1,3> 
> +1<t_y_163> +392 <= 1e+20
> 
> I'd appreciate any help! Also, is there any way so that I can print all 
> the current rows in the LP? My idea was to print all rows in the LP 
> before SCIP adds the same row the second time, so that I can check that 
> indeed the row was added the first time.
> 
> Thanks,
> Matheus
> 
> _______________________________________________
> Scip mailing list
> Scip at zib.de
> https://listserv.zib.de/mailman/listinfo/scip
>