[Scip] Column generation

[Marco Lübbecke]

2014-03-12 21:44 GMT+01:00 Mahdi Noorizadegan (DIMAP) <
phd09mn at mail.wbs.ac.uk>:

> the reduced cost of column is equal to
> the main cost of a column - the dual values
>

just to be sure. "main cost of a column - the dual values" means: c - pi *
a, where c is a number (the new variable's cost), pi is the vector of dual
variables, and a is the vector of coefficients of the new variable?

when something happens what you describe I am almost certain that your
reduced cost computation has a bug. Also: what is "negative"? Do you
compare against 0.0, or do you use the SCIP methods to compare for
negativity up to certain tolerances?

Marco
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