[Coin-discuss] Manual copying of an OSI LP object

[Jonathan Eckstein]

Dear COIN/OSIers:

I need to make a copy of an OsiSolverInterface object (specifically an 
OsiClpInterface object).  I tried using the "clone" method, and although 
it works OK on some systems, it did not work properly on one system, the 
weird 9000-processor machine at Sandia that uses the Portland group 
cross-compilers.  On that system, "clone" seems to damage the object 
being copied, so that GetColSolution always returns zero vectors.  I 
suspect it is some kind of compiler bug or obsoleteness.

I guess I could have tried the copy constructor instead, but I first 
tried the following simple kind of workaround:

	  OsiSolverInterface* copy = new OsiClpInterface;
	  copy->loadProblem(*(original->getMatrixByRow()),
			    original->getColLower(),
			    original->getColUpper(),
			    original->getObjCoefficients(),
			    original->getRowLower(),
			    original->getRowUpper());

I can also imagine this kind of thing would be useful if you wanted ot 
copy an LP, but change solvers.  It *seemed* to work, but I am curious 
if there are any important aspects of the problem description that might 
be missed and would still need to be transferred from the original to 
the copy.  I don't care about the solver's internal state etc., just the 
full description of the problem.

Thanks,

    Jonathan