[Coin-lpsolver] getPrimalRay()

[Anureet Saxena]

hi John,

Thanks for your reply.
Setting OsiDoPresolveInInitial to false (using setHintParam()) does switch off
the presolve, but it does not resolve the problem. The extreme ray returned
still has the same large numbers.

Scaling is indeed a solution but it is not very good and affects other parts of
the code, as you pointed out.

I was wondering if there is a way to extract extreme rays from the tableau
using the textbook method of using columns with no pivotable row. The good
thing about that approach is that if the problem has numerically stable basis,
then the extreme ray will also have reasonably sized coefficients. Please
excuse me if this is too much to ask frm the current implementation in OsiClp,
as I am not at all familiar with the details.

If anyone has worked with extracting extreme rays using OsiClp and has an
approach to avoid very large numbers, please let me know.

Thanks for your replies,
Regards,
Anureet Saxena



Anureet Saxena
 anureet at cmu.edu
 anureet at yahoo.com
 
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