[SCIP] Error: constraint is not linear

[mahdi noorizadegan]

 Hi Gerald,

I have a pricing procedure which finds variables with negative reduced cost.
Once they are found they are added to the master problem. However, the .lp
file via SCIPwriteTransProblem is not created after addition. It is set to
create .lp file after addition of variables.

I do cout "check" at the end of the variable adding function (before return
SCIP_OKAY) and also after call for this function. While it leaves the
function and starts the pricing procedure, it does not print the check
point after the var adding function. Therefore no .lp file is created.
Could you please let me know what I have done wrong?

Regards,
Mahdi


On Sat, 25 May 2019 at 12:58, Gerald Gamrath <gamrath at zib.de> wrote:

> 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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