[SCIP] Error: constraint is not linear

[Gerald Gamrath]

Dear Mahdi,

even if you create a model with only linear constraints, SCIP might 
upgrade them in presolving to specialized linear constraints like 
knapsack or set cover constraints. SCIP does not do this if you marked a 
constraint to be modifiable, which you should have done if priced 
variables will potentially be added to the constraint. On the other 
hand, if you will not add any priced variables to the constraint, you 
don't need to mark it to be modifiable, but you should also not need its 
dual value.

I would suggest you check what type the constraint has via 
SCIPconshdlrGetName(SCIPconsGetHdlr(cons)) either in gdb or in your code.

Best,
Gerald

On 22.05.19 14:45, mahdi noorizadegan wrote:
> Hello,
>
> I am implementing an IP using branch and price method.
> When I want to get the dual value of constraints which are all linear, 
> I get the following error
>
> [src/scip/cons_linear.c:17033] ERROR: constraint is not linear
>
> What can be wrong?
>
> Looking forward to hearing from you,
> Regards,
> Mahdi
>
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