[Scip] Column generation

[Gerald Gamrath]

Hi Mahdi,

in addition to that: When the optimal reduced cost is zero (and you 
should really use some tolerance as Marco suggests!), do you add a 
variable anyway? SCIP will continue pricing as long as you add variables 
and only stop, if you didn't add any new variables in the last round.

Another thing: Do you add cutting planes? After that, pricing needs to 
be done again.

Can you send me a log file of your run (including statistics), then I 
can have a look at it.

Best,
Gerald

Am 12.03.2014 23:29, schrieb Marco Lübbecke:
>
> 2014-03-12 21:44 GMT+01:00 Mahdi Noorizadegan (DIMAP) 
> <phd09mn at mail.wbs.ac.uk <mailto: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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