[Coin-lpsolver] ClpSolve problem

[John J Forrest]

Totally my stupidity - is it better now. 

I have added your patches (they broke CBC but I fixed that)

John



François Galea <francois.galea at prism.uvsq.fr> 
Sent by: coin-lpsolver-bounces at list.coin-or.org
06/30/2005 07:01 AM

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coin-lpsolver at list.coin-or.org
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Subject
[Coin-lpsolver] ClpSolve problem






Hello,

I have met several segmentation fault errors, when I use the 
ClpSimplex::initialSolve( ClpSolve & ) method for starting a new solve.

The example attached program doesn't work, if I choose to switch 
presolve off. If I switch it on, everything works (provided the Clp 
sources have been patched with the patch I sent before, otherwise the 
names changes won't work). Some other pieces of code I've got crash even 
if I set presolve on.

I haven't understood enough the internals of ClpSimplex and ClpModel to 
be sure about what is wrong.

Could somebody tell me what's wrong ?

Thanks,

François


-- 
François Galea
Equipe OPALE - Laboratoire PRiSM
Université de Versailles-Saint Quentin en Yvelines
45 av Etats-Unis F-78035 Versailles CEDEX
Tél. : +33 1 39 25 40 50

#include <cstdio>

#include "ClpSimplex.hpp"
#include "CoinBuild.hpp"

int main( int argc, char * argv[] )
{
  const static struct { double a, b, c, d; } p [] =
  {
    { 5.0, 0.0, 7.0, 3.0 },
    { 8.0, 0.0, 7.0, 6.0 },
    { 0.0, 10.0, 3.0, 9.0 },
    { 1.0, 8.0, 5.0, 9.0 },
    { 2.0, 0.0, 0.0, 7.0 },
    { 0.0, 4.0, 5.0, 0.0 },
    { 0.0, 1.0, 6.0, 2.0 },
    { 2.0, 0.0, 8.0, 3.0 }
  };
  const static char * columnNames [2] = { "x", "y" };
  double k, obj;
  char buf[ 10 ];
  char * rowname = buf;
  double val[ 2 ];
  int ind[ 2 ];
  unsigned int i;
  const double * sol;
  ClpSimplex lp;
  CoinBuild * buildObject;
  ClpSolve * solveOptions;

  lp.setStrParam( ClpProbName, "foo" );

  buildObject = new CoinBuild( 1 );
  buildObject->addCol( 0, NULL, NULL, 0.0, +COIN_DBL_MAX, 4 );
  buildObject->addCol( 0, NULL, NULL, 0.0, +COIN_DBL_MAX, 3 );
  lp.addColumns( *buildObject );
  delete buildObject;
  lp.copyColumnNames( columnNames, 0, 2 );

  buildObject = new CoinBuild( 0 );
  ind[ 0 ] = 0;
  ind[ 1 ] = 1;
  for( i = 0; i < (sizeof( p ) / sizeof( p[0] )); i++ )
  {
    k = p[i].a * p[i].d - p[i].c * p[i].b;
    val[0] = (p[i].d-p[i].b)/k;
    val[1] = (p[i].a-p[i].c)/k;
 
    if( ((1.0-val[0]*4.0)/val[1]) > 5.0 )
      buildObject->addRow( 2, ind, val, 0.0, 1.0 );
    else
      buildObject->addRow( 2, ind, val, 1.0, +COIN_DBL_MAX );
  }
  lp.setOptimizationDirection( -1.0 );
  lp.addRows( *buildObject );
  for( i = 0; i < (sizeof( p ) / sizeof( p[0] )); i++ )
  {
    sprintf( buf, "c%d", i );
    lp.copyRowNames( &rowname, i, i+1 );
  }
  delete buildObject;

  solveOptions = new ClpSolve();
  solveOptions->setSolveType( ClpSolve::useDual );
  solveOptions->setPresolveType( ClpSolve::presolveOff, 0 );
  // solveOptions->setPresolveType( ClpSolve::presolveOn, 5 );
  lp.setLogLevel( 1 );
  lp.initialSolve( *solveOptions );
  delete solveOptions;

  lp.writeMps( "foo.mps" );

  obj = -lp.rawObjectiveValue();
  sol = lp.getColSolution();

  printf( "obj = %f\nx = %f\ny = %f\n", obj, sol[ 0 ], sol[ 1 ] );

  return 0;
}
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