[Osi] memory leaks in OSI/CLP

[John J Forrest]

Thanks - patch will go in.


                                                                                                   
  From:       Renaud Lepere <Renaud.Lepere at alma.fr>                                                
                                                                                                   
  To:         "osi at list.coin-or.org" <osi at list.coin-or.org>                                        
                                                                                                   
  Date:       09/15/2009 10:17 AM                                                                  
                                                                                                   
  Subject:    [Osi] memory leaks in OSI/CLP                                                        
                                                                                                   
  Sent by:    osi-bounces at list.coin-or.org                                                         
                                                                                                   






Hello,

 I am using OSI/CLP to solve a lot of linear programs, some of them
are impossible, but i have found some memory leaks on some problems.
I have instrumented my code to produce a standalone program that
reproduce the leak, apparently the leak is within Clp code.
I have gone a bit further i think leak.patch should solve the
problem.

Renaud,


Roughly my code is something like :
 void test_xx() {
		 OsiSolverInterface * solver(new OsiClpSolverInterface());
		 solver->reset();

		 solver->addCol(0, 0, 0, lb1, ub1, obj1);
		 ...
		 solver->addRow(...);

		 solver->initialSolve();
      delete solver;
 }

The complete and standalone program is test_osi.cpp with includes
osi_16_9433435.inl, this file is a sort of log of the call i'm
doing to osi (double values are encoded exactly using long long).

test_osi.cpp contains also a small memory leak detector. The output
of the program on

Clp0024I Matrix will be packed to eliminate 307 small elements
Coin0506I Presolve 892 (-770) rows, 228 (-88) columns and 1784 (-1161)
elements
Clp0009I 1 infeasibilities
Clp3003W Analysis indicates model infeasible or unbounded
Clp0006I 0  Obj 9726.95 Primal inf 203.146 (9)
Clp0006I 27  Obj 9738.14 Primal inf 168.766 (27)
Clp0001I Primal infeasible - objective value 9738.14
Clp0032I PrimalInfeasible objective 9738.139668 - 27 iterations time 0.082
Clp0006I 0  Obj 9738.14 Primal inf 168.766 (27)
Clp0006I 4  Obj 9738.14 Primal inf 185.375 (37)
Clp0001I Primal infeasible - objective value 9738.14
nbLeak: 43, nbAlloc: 21072

Using mmgr i located more precisely the leak, here is the call stack
>		 test_osid.exe!ClpPresolve::gutsOfPresolvedModel(ClpSimplex *
originalModel=0x0032b850, double
feasibilityTolerance=1.0000000000000000e-008, bool keepIntegers=false, int
numberPasses=5, bool dropNames=true, bool doRowObjective=false)  Ligne 1521
+ 0xa octets		 C++
 		 test_osid.exe!ClpPresolve::presolvedModel(ClpSimplex & si=
{...}, double feasibilityTolerance=1.0000000000000000e-008, bool
keepIntegers=false, int numberPasses=5, bool dropNames=true, bool
doRowObjective=false)  Ligne 105		 C++
 		 test_osid.exe!ClpSimplex::initialSolve(ClpSolve & options=
{...})  Ligne 485 + 0x33 octets		 C++
 		 test_osid.exe!OsiClpSolverInterface::initialSolve()  Ligne 694
	 C++

Apparently the memory is lost when  model2 = this; line 906 in clpsolve.cpp

i just added delete model2 line to fix the problem.
                handler_->message(CLP_INFEASIBLE,messages_)
<<CoinMessageEol;
->              delete model2;
                model2 = this;

[attachment "leak.patch" deleted by John J Forrest/Watson/IBM] [attachment
"osi_16_9433435.inl.gz" deleted by John J Forrest/Watson/IBM] [attachment
"test_osi.cpp" deleted by John J Forrest/Watson/IBM]
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