[SCIP] Transformed Problem + Infeasible solution at Constraint Handler

[Matheus Ota]

Hi all,

First I would like to say that I'm very grateful for all the help I
received from this mailing list! I have a question regarding a MIP model
that I'm solving. I have some equalities of the following type

> x_i,0 + x_i,1 == 1, for i = 0, ..., 8 (*)
>

Thus, SCIP presolve routines replace some of my variables (x_i,0) by the
negation of other variables (1 - x_i,1). In the transformed model I have
only this constraint


[knapsack] <R>: +1<~t_x_8,1>[B] +1<~t_x_7,1>[B] +1<~t_x_6,1>[B]
> +1<~t_x_5,1>[B] +1<~t_x_4,1>[B] +1<~t_x_3,1>[B] +1<~t_x_2,1>[B]
> +1<~t_x_1,1>[B] +1<~t_x_0,1>[B] <= 4;
>

 And each variable x is binary. The tilde (~) means negation here? If so,
replacing <~t_x_i,1> by <t_x_i,0> this would give

> <t_x_8,0> + ... + <t_x_0,0><= 4 (**)
>

But at the CONSENFOLP method, SCIP is entering with a "solution" S with
x_i,0 = 1 and x_i,1 = 0, for i = 0, ..., 8. Which is infeasible because
violates (**). But the SCIP documentation says that CONSENFOLP is called
when an LP solution is available. But this solution S do not respect the
constraints in my LP. I'm a little confused with this behavior and would be
glad if someone could give me some light here.

Thanks!
Matheus
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