AdaptiveSA.cpp

/* ******************************************************************** */
/* See the file COPYRIGHT for a complete copyright notice, contact      */
/* person and disclaimer.                                               */        
/* ******************************************************************** */

#include "ml_config.h"
#include "ml_common.h"
#ifdef HAVE_ML_MLAPI
#include "MLAPI_Space.h"
#include "MLAPI_Operator.h"
#include "MLAPI_MultiVector.h"
#include "MLAPI_Expressions.h"
#include "MLAPI_MultiLevelAdaptiveSA.h"
#include "MLAPI_DistributedMatrix.h"
#include "MLAPI_Krylov.h"

using namespace Teuchos;
using namespace MLAPI;

// =========== //
// main driver //
// =========== //

int main(int argc, char *argv[])
{

#ifdef HAVE_MPI
  MPI_Init(&argc,&argv);
#endif

  try {

    // Initialize the workspace and set the output level
    Init();

    int NX = 1000;

    // define the space for fine level vectors and operators.
    Space FineSpace(2*NX);

    DistributedMatrix A(FineSpace, FineSpace);

    // assemble the matrix on processor 0 only
    if (GetMyPID() == 0) 
    {
      for (int i = 0 ; i < NX ; ++i) 
      {
        A(2*i, 2*i)     = 2.0;
        A(2*i+1, 2*i+1) = 2.0;
        if (i)
        {
          A(2*i, 2*(i - 1))     = - 1.0;
          A(2*i+1, 2*(i - 1)+1) = - 1.0;
        }
        if (i != NX - 1) 
        {
          A(2*i, 2*(i + 1))     = - 1.0;
          A(2*i+1, 2*(i + 1)+1) = - 1.0;
        }
      }
    }
    A.FillComplete();

    int NumPDEEqns = 2;
    int MaxLevels = 10;

    Teuchos::ParameterList List;
    List.set("additional candidates", 2);
    List.set("use default null space", true);
    List.set("krylov: type", "cg");

    MultiLevelAdaptiveSA Prec(A, List, NumPDEEqns, MaxLevels);

    // =============================================================== //
    // setup the hierarchy:                                            //
    // - `UseDefaultNullSpace' toggles the use of default candidates.  //
    // - AdditionalCandidates = 2' means to compute two additionals.   //
    // - the final null space dimension is 3.                          //
    // =============================================================== //
    
    bool UseDefaultNullSpace = true;
    int AdditionalCandidates = 1;
    Prec.AdaptCompute(UseDefaultNullSpace, AdditionalCandidates);

    MultiVector LHS(A.GetDomainSpace());
    MultiVector RHS(A.GetRangeSpace());

    LHS.Random();
    RHS = 0.0;

    Krylov(A, LHS, RHS, Prec, List);

    Finalize(); 

  }
  catch (const int e) {
    cerr << "Caught integer exception, code = " << e << endl;
  }
  catch (...) {
    cerr << "Caught exception..." << endl;
  }

#ifdef HAVE_MPI
  MPI_Finalize() ;
#endif

  return(0);

}

#else

#include "ml_include.h"

int main(int argc, char *argv[])
{
#ifdef HAVE_MPI
  MPI_Init(&argc,&argv);
#endif

  puts("This MLAPI example requires the following configuration options:");
  puts("\t--enable-epetra");
  puts("\t--enable-teuchos");
  puts("\t--enable-ifpack");
  puts("\t--enable-amesos");
  puts("Please check your configure line.");

#ifdef HAVE_MPI
  MPI_Finalize();
#endif

  return(0);
}
#endif // #if defined(HAVE_ML_MLAPI)