[Osi-tickets] [COIN-OR Open Solver Interface] #69: Positivity box constraints on the variables are in even if they should not...

[COIN-OR Open Solver Interface]

#69: Positivity box constraints on the variables are in even if they should
not...
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 Reporter:  coniglio        |       Owner:  mjs 
     Type:  defect          |      Status:  new 
 Priority:  major           |   Milestone:      
Component:  Osi Base Class  |     Version:  0.96
 Keywords:                  |  
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 After loading a .mps or .lp instance, with a plain:
     OsiClpSolverInterface solver;
     if (extention == "lp") solver.readLp(filename.c_str());
     else solver.readMps(filename.c_str());
 when checking the lower and upper bounds on the variables, with:
     const double* clb = solver.getColLower();
     const double* cub = solver.getColUpper();
 I am finding the lower bounds in clb to be always set to 0, even if the
 variables in the instance file were unbounded.

 Simple example: I get a (0,0) solution to the problem:
   Minimize
   obj:  x0 + x1
   Subject To
   c0:  x0 + x1 >= -1
   End
 whereas the optimum should be attained at (-0.5, -0.5).

-- 
Ticket URL: <https://projects.coin-or.org/Osi/ticket/69>
COIN-OR Open Solver Interface <http://projects.coin-or.org/Osi>
An API for a variety of LP and MIP solvers (and more).