[Scip] Column generation

[Mahdi Noorizadegan (DIMAP)]

Hi,

I am solving a problem by the column generation method.
After few iteration of solving the pricing problem, the negative reduced
cost is zero.
But the algorithm does not branch instead, it keeps solving the pricing
problem.
After a couple of iteration with positive or zero reduced cost, it finds a
negative reduced cost.
The new column is added to the master problem but here is loop i.e.,
again the reduced cost is zero or positive for a couple of iteration and
again the same negative
reduced cost is found. Note that all reduced costs for this loop stay the
same.


I have checked the pricing problem, it is correct. at least, the reduced
cost of column is equal to
the main cost of a column - the dual values.

What can be wrong? what should I do to branch if the reduced cost is not
negative?

Regards,
Mahdi
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