[Coin-discuss] OsiSolverInterface use and in particularOsiClpSolverInterface

[Jonathan Eckstein]

One thing that has come up in the past in our MIP heuristic is 

   <starting with non-empty model>
   Add some empty columns
   Add new rows with coefficients in these columns
     (including some with coefs in the prior columns as well)

It would be nice if this and vice versa would work.  We've run into
trouble because some solvers won't let you add empty rows or columns.

   Jonathan


John J Forrest wrote:
> 
> I am going to make sure that the following works in Clp:
> 
> empty model
> add rows (with no elements)
> add columns (with elements)
> 
> and the other way round.  I don't like the idea of implicitly adding
> columns by adding rows.
> 
> I have modified unitTest.cpp but I have not checked it in - should I as it
> may break other solvers?  For instance it semi-broke Osl  (it complained
> about rows with no elements).  At present Clp does fail ungracefully.  I
> should have that fixed in a few hours.
> 
> John
> 
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-- 

Associate Professor Jonathan Eckstein
MSIS Department, Rutgers Business School, Rutgers University

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