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