Exemple #1
0
// ====================================================================== 
double MaxEigPowerMethod(const Operator& Op, const bool DiagonalScaling) 
{

  ML_Krylov *kdata;
  double MaxEigen;

    kdata = ML_Krylov_Create(GetML_Comm());
    if (DiagonalScaling == false)
      kdata->ML_dont_scale_by_diag = ML_TRUE;
    else
      kdata->ML_dont_scale_by_diag = ML_FALSE;
    ML_Krylov_Set_PrintFreq(kdata, 0);
    ML_Krylov_Set_ComputeNonSymEigenvalues(kdata);
    ML_Krylov_Set_Amatrix(kdata, Op.GetML_Operator());
    ML_Krylov_Solve(kdata, Op.GetML_Operator()->outvec_leng, NULL, NULL);
    MaxEigen = ML_Krylov_Get_MaxEigenvalue(kdata);
  ML_Krylov_Destroy(&kdata);

  return(MaxEigen);
}
Exemple #2
0
int main(int argc, char *argv[]){


   ML *ml_object;
   int i, N_grids = 3, N_levels;
   double sol[129], rhs[129];
   ML_Aggregate *agg_object;
   ML_Operator *data;
   ML_Krylov *kdata;

#ifdef ML_MPI
   MPI_Init(&argc,&argv);
#endif
   for (i = 0; i < 129; i++) sol[i] = 0.;
   for (i = 0; i < 129; i++) rhs[i] = 2.;


   ML_Create         (&ml_object, N_grids);

   ML_Init_Amatrix      (ml_object, 0,  129, 129, NULL);
   ML_Set_Amatrix_Getrow(ml_object, 0,  Poisson_getrow, NULL, 129);
   ML_Set_Amatrix_Matvec(ml_object, 0,  Poisson_matvec);
   ML_Set_PrintLevel(10);

   ML_Aggregate_Create(&agg_object);
   ML_Aggregate_Set_MaxCoarseSize(agg_object,1);
   N_levels = ML_Gen_MGHierarchy_UsingAggregation(ml_object, 0,
                                                  ML_INCREASING, agg_object);
   /******** Begin code to set a Jacobi smoother ******

   ML_Gen_Smoother_Jacobi(ml_object, ML_ALL_LEVELS, ML_PRESMOOTHER, 1, ML_DEFAULT);

    ******** End code to set a Jacobi smoother ******/

   /******** Begin code to set a user-defined smoother ******/
   ML_Get_Amatrix(ml_object, 0, &data);
   ML_Set_Smoother(ml_object, 0, ML_BOTH, data, user_smoothing,"mine");
   ML_Get_Amatrix(ml_object, 1, &data);
   ML_Set_Smoother(ml_object, 1, ML_BOTH, data, user_smoothing,"mine");
   ML_Get_Amatrix(ml_object, 2, &data);
   ML_Set_Smoother(ml_object, 2, ML_BOTH, data, user_smoothing,"mine");
   ML_Gen_Solver    (ml_object, ML_MGV, 0, N_levels-1);

   /* This example uses an internal CG solver within ML     */
   /* ML has limited Krylov methods support. It is intended */
   /* that ML be used with another package that supplies    */
   /* more sophisticated Krylov solver options (such as those */
   /* found in the Trilinos or Aztec packages.              */

   kdata = ML_Krylov_Create(ml_object->comm);
   ML_Krylov_Set_PrintFreq( kdata, 1 );
   ML_Krylov_Set_Method(kdata, ML_CG);
   ML_Krylov_Set_Amatrix(kdata, &(ml_object->Amat[0]));
   ML_Krylov_Set_PreconFunc(kdata, ML_MGVSolve_Wrapper);
   ML_Krylov_Set_Precon(kdata, ml_object);
   ML_Krylov_Set_Tolerance(kdata, 1.e-7);
   ML_Krylov_Solve(kdata, 129, rhs, sol);
   ML_Krylov_Destroy( &kdata );

   ML_Aggregate_Destroy(&agg_object);
   ML_Destroy(&ml_object);
   /******** End code to set a user-defined smoother ******/

   printf("answer is %e %e %e %e %e\n",sol[0],sol[1],sol[2],sol[3],sol[4]);

#ifdef ML_MPI
  MPI_Finalize();
#endif
  exit(EXIT_SUCCESS);
}