[Coin-discuss] OsiClpSolverInterface::modifyCoefficient problems

[James Gibbons]

John,

Thanks for the quick response. You're right just calling initalSolve means the assert message doesn't appear. I also get

Clp0024I Matrix will be packed to eliminate 6965 small elements

Which I guess is to do with writing lots of zeros

James


Seems like you have hit two separate bugs.  I would guess the second one 
is a bug in OsiPresolve.  It looks as if ClpPresolve gets rid of zero 
elements before doing main part of presolve.  What happens if you don't do 
OsiPresolve but just call OsiClpSolverInterface::initialSolve() - it 
should do a ClpPresolve and so should be OK?  I will see if you have given 
enough information for me to track down first bug.  I will try to have 
that fixed by Monday.  If I have the time and energy I may move a function 
- allElementsInRange from ClpPackedMatrix to CoinPackedMatrix and then it 
will be easy to modify OsiPresolve.


John Forrest

-- 
Dr James Gibbons
Research Fellow
Division of Agricultural & Environmental Sciences
School of Biosciences
University of Nottingham
Sutton Bonington Campus
Loughborough
LE12 5RD

direct line: 0115 9516081
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e-mail:       james.gibbons at nottingham.ac.uk

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