[Coin-lpsolver] providing a basis for Clp

[John J Forrest]

Richard,

Yes.  Although the C interface is a bit rudimentary there are getRowStatus 
and getColumnStatus which return ints which correspond to the enum in 
ClpSimplex.hpp (and also given in C header file).  I noticed that there 
was no setRow/ColumnStatus so have written but not tested them.

One can give a partial basis.  If there are too many basic Clp throws rest 
out so it may be a good idea to set all/some row slacks non basic.  There 
can be too few basic.  After a factorization Clp will throw out singular 
variables and then re-fill basis using slacks. 

If you have trouble (especially with the setStatus I just wrote), please 
tell me.

John Forrest





Richard Waltz <rwaltz at ece.northwestern.edu> 
Sent by: coin-lpsolver-bounces at list.coin-or.org
05/30/2005 10:28 AM
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[Coin-lpsolver] providing a basis for Clp






Can one specify an initial basis for the Clp solver to speed up the 
solution?  If so, can it be done through the C interface?  Also, more 
specifically, can one provide a partial basis if a complete basis is not 
know?  What will Clp do in this case?

-Richard Waltz

-- 
=======================================
Richard A. Waltz
Assistant Research Professor
Electrical & Computer Engineering Dept.
Northwestern University
rwaltz at ece.northwestern.edu
www.ece.northwestern.edu/~rwaltz/

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