Exemple #1
0
void HypreSolver2D::build_solver()
{

	HYPRE_BoomerAMGCreate(&solver);
	//HYPRE_BoomerAMGSetPrintLevel(solver, 3);  /* print solve info + parameters */
	HYPRE_BoomerAMGSetCoarsenType(solver, 6); /* Falgout coarsening */
	HYPRE_BoomerAMGSetRelaxType(solver, 3);   /* G-S/Jacobi hybrid relaxation */
	HYPRE_BoomerAMGSetNumSweeps(solver, 1);   /* Sweeeps on each level */
	HYPRE_BoomerAMGSetMaxLevels(solver, 20);  /* maximum number of levels */
	HYPRE_BoomerAMGSetTol(solver, 1e-7);      /* conv. tolerance */

	HYPRE_BoomerAMGSetup(solver, parcsr_A, par_b, par_x);
	
}
Exemple #2
0
HYPRE_Int hypre_seqAMGSetup( hypre_ParAMGData *amg_data,
                      HYPRE_Int p_level,
                      HYPRE_Int coarse_threshold)


{

   /* Par Data Structure variables */
   hypre_ParCSRMatrix **Par_A_array = hypre_ParAMGDataAArray(amg_data);

   MPI_Comm 	      comm = hypre_ParCSRMatrixComm(Par_A_array[0]); 
   MPI_Comm 	      new_comm, seq_comm;

   hypre_ParCSRMatrix   *A_seq = NULL;
   hypre_CSRMatrix  *A_seq_diag;
   hypre_CSRMatrix  *A_seq_offd;
   hypre_ParVector   *F_seq = NULL;
   hypre_ParVector   *U_seq = NULL;

   hypre_ParCSRMatrix *A;

   HYPRE_Int               **dof_func_array;   
   HYPRE_Int                num_procs, my_id;

   HYPRE_Int                not_finished_coarsening;
   HYPRE_Int                level;

   HYPRE_Solver  coarse_solver;

   /* misc */
   dof_func_array = hypre_ParAMGDataDofFuncArray(amg_data);

   /*MPI Stuff */
   hypre_MPI_Comm_size(comm, &num_procs);   
   hypre_MPI_Comm_rank(comm,&my_id);
  
   /*initial */
   level = p_level;
   
   not_finished_coarsening = 1;
  
   /* convert A at this level to sequential */
   A = Par_A_array[level];

   {
      double *A_seq_data = NULL;
      HYPRE_Int *A_seq_i = NULL;
      HYPRE_Int *A_seq_offd_i = NULL;
      HYPRE_Int *A_seq_j = NULL;

      double *A_tmp_data = NULL;
      HYPRE_Int *A_tmp_i = NULL;
      HYPRE_Int *A_tmp_j = NULL;

      HYPRE_Int *info, *displs, *displs2;
      HYPRE_Int i, j, size, num_nonzeros, total_nnz, cnt;
  
      hypre_CSRMatrix *A_diag = hypre_ParCSRMatrixDiag(A);
      hypre_CSRMatrix *A_offd = hypre_ParCSRMatrixOffd(A);
      HYPRE_Int *col_map_offd = hypre_ParCSRMatrixColMapOffd(A);
      HYPRE_Int *A_diag_i = hypre_CSRMatrixI(A_diag);
      HYPRE_Int *A_offd_i = hypre_CSRMatrixI(A_offd);
      HYPRE_Int *A_diag_j = hypre_CSRMatrixJ(A_diag);
      HYPRE_Int *A_offd_j = hypre_CSRMatrixJ(A_offd);
      double *A_diag_data = hypre_CSRMatrixData(A_diag);
      double *A_offd_data = hypre_CSRMatrixData(A_offd);
      HYPRE_Int num_rows = hypre_CSRMatrixNumRows(A_diag);
      HYPRE_Int first_row_index = hypre_ParCSRMatrixFirstRowIndex(A);

      hypre_MPI_Group orig_group, new_group; 
      HYPRE_Int *ranks, new_num_procs, *row_starts;

      info = hypre_CTAlloc(HYPRE_Int, num_procs);

      hypre_MPI_Allgather(&num_rows, 1, HYPRE_MPI_INT, info, 1, HYPRE_MPI_INT, comm);

      ranks = hypre_CTAlloc(HYPRE_Int, num_procs);

      new_num_procs = 0;
      for (i=0; i < num_procs; i++)
         if (info[i]) 
         {
            ranks[new_num_procs] = i;
            info[new_num_procs++] = info[i];
         }

      MPI_Comm_group(comm, &orig_group);
      hypre_MPI_Group_incl(orig_group, new_num_procs, ranks, &new_group);
      MPI_Comm_create(comm, new_group, &new_comm);
      hypre_MPI_Group_free(&new_group);
      hypre_MPI_Group_free(&orig_group);

      if (num_rows)
      {
         /* alloc space in seq data structure only for participating procs*/
         HYPRE_BoomerAMGCreate(&coarse_solver);
         HYPRE_BoomerAMGSetMaxRowSum(coarse_solver,
		hypre_ParAMGDataMaxRowSum(amg_data)); 
         HYPRE_BoomerAMGSetStrongThreshold(coarse_solver,
		hypre_ParAMGDataStrongThreshold(amg_data)); 
         HYPRE_BoomerAMGSetCoarsenType(coarse_solver,
		hypre_ParAMGDataCoarsenType(amg_data)); 
         HYPRE_BoomerAMGSetInterpType(coarse_solver,
		hypre_ParAMGDataInterpType(amg_data)); 
         HYPRE_BoomerAMGSetTruncFactor(coarse_solver, 
		hypre_ParAMGDataTruncFactor(amg_data)); 
         HYPRE_BoomerAMGSetPMaxElmts(coarse_solver, 
		hypre_ParAMGDataPMaxElmts(amg_data)); 
	 if (hypre_ParAMGDataUserRelaxType(amg_data) > -1) 
            HYPRE_BoomerAMGSetRelaxType(coarse_solver, 
		hypre_ParAMGDataUserRelaxType(amg_data)); 
         HYPRE_BoomerAMGSetRelaxOrder(coarse_solver, 
		hypre_ParAMGDataRelaxOrder(amg_data)); 
         HYPRE_BoomerAMGSetRelaxWt(coarse_solver, 
		hypre_ParAMGDataUserRelaxWeight(amg_data)); 
	 if (hypre_ParAMGDataUserNumSweeps(amg_data) > -1) 
            HYPRE_BoomerAMGSetNumSweeps(coarse_solver, 
		hypre_ParAMGDataUserNumSweeps(amg_data)); 
         HYPRE_BoomerAMGSetNumFunctions(coarse_solver, 
		hypre_ParAMGDataNumFunctions(amg_data)); 
         HYPRE_BoomerAMGSetMaxIter(coarse_solver, 1); 
         HYPRE_BoomerAMGSetTol(coarse_solver, 0); 

         /* Create CSR Matrix, will be Diag part of new matrix */
         A_tmp_i = hypre_CTAlloc(HYPRE_Int, num_rows+1);

         A_tmp_i[0] = 0;
         for (i=1; i < num_rows+1; i++)
            A_tmp_i[i] = A_diag_i[i]-A_diag_i[i-1]+A_offd_i[i]-A_offd_i[i-1];

         num_nonzeros = A_offd_i[num_rows]+A_diag_i[num_rows];

         A_tmp_j = hypre_CTAlloc(HYPRE_Int, num_nonzeros);
         A_tmp_data = hypre_CTAlloc(double, num_nonzeros);

         cnt = 0;
         for (i=0; i < num_rows; i++)
         {
            for (j=A_diag_i[i]; j < A_diag_i[i+1]; j++)
	    {
	       A_tmp_j[cnt] = A_diag_j[j]+first_row_index;
	       A_tmp_data[cnt++] = A_diag_data[j];
	    }
            for (j=A_offd_i[i]; j < A_offd_i[i+1]; j++)
	    {
	       A_tmp_j[cnt] = col_map_offd[A_offd_j[j]];
	       A_tmp_data[cnt++] = A_offd_data[j];
	    }
         }

         displs = hypre_CTAlloc(HYPRE_Int, new_num_procs+1);
         displs[0] = 0;
         for (i=1; i < new_num_procs+1; i++)
            displs[i] = displs[i-1]+info[i-1];
         size = displs[new_num_procs];
  
         A_seq_i = hypre_CTAlloc(HYPRE_Int, size+1);
         A_seq_offd_i = hypre_CTAlloc(HYPRE_Int, size+1);

         hypre_MPI_Allgatherv ( &A_tmp_i[1], num_rows, HYPRE_MPI_INT, &A_seq_i[1], info, 
			displs, HYPRE_MPI_INT, new_comm );

         displs2 = hypre_CTAlloc(HYPRE_Int, new_num_procs+1);

         A_seq_i[0] = 0;
         displs2[0] = 0;
         for (j=1; j < displs[1]; j++)
            A_seq_i[j] = A_seq_i[j]+A_seq_i[j-1];
         for (i=1; i < new_num_procs; i++)
         {
            for (j=displs[i]; j < displs[i+1]; j++)
            {
               A_seq_i[j] = A_seq_i[j]+A_seq_i[j-1];
            }
         }
         A_seq_i[size] = A_seq_i[size]+A_seq_i[size-1];
         displs2[new_num_procs] = A_seq_i[size];
         for (i=1; i < new_num_procs+1; i++)
         {
            displs2[i] = A_seq_i[displs[i]];
            info[i-1] = displs2[i] - displs2[i-1];
         }

         total_nnz = displs2[new_num_procs];
         A_seq_j = hypre_CTAlloc(HYPRE_Int, total_nnz);
         A_seq_data = hypre_CTAlloc(double, total_nnz);

         hypre_MPI_Allgatherv ( A_tmp_j, num_nonzeros, HYPRE_MPI_INT,
                       A_seq_j, info, displs2,
                       HYPRE_MPI_INT, new_comm );

         hypre_MPI_Allgatherv ( A_tmp_data, num_nonzeros, hypre_MPI_DOUBLE,
                       A_seq_data, info, displs2,
                       hypre_MPI_DOUBLE, new_comm );

         hypre_TFree(displs);
         hypre_TFree(displs2);
         hypre_TFree(A_tmp_i);
         hypre_TFree(A_tmp_j);
         hypre_TFree(A_tmp_data);
   
         row_starts = hypre_CTAlloc(HYPRE_Int,2);
         row_starts[0] = 0; 
         row_starts[1] = size;
 
         /* Create 1 proc communicator */
         seq_comm = hypre_MPI_COMM_SELF;

         A_seq = hypre_ParCSRMatrixCreate(seq_comm,size,size,
					  row_starts, row_starts,
						0,total_nnz,0); 

         A_seq_diag = hypre_ParCSRMatrixDiag(A_seq);
         A_seq_offd = hypre_ParCSRMatrixOffd(A_seq);

         hypre_CSRMatrixData(A_seq_diag) = A_seq_data;
         hypre_CSRMatrixI(A_seq_diag) = A_seq_i;
         hypre_CSRMatrixJ(A_seq_diag) = A_seq_j;
         hypre_CSRMatrixI(A_seq_offd) = A_seq_offd_i;

         F_seq = hypre_ParVectorCreate(seq_comm, size, row_starts);
         U_seq = hypre_ParVectorCreate(seq_comm, size, row_starts);
         hypre_ParVectorOwnsPartitioning(F_seq) = 0;
         hypre_ParVectorOwnsPartitioning(U_seq) = 0;
         hypre_ParVectorInitialize(F_seq);
         hypre_ParVectorInitialize(U_seq);

         hypre_BoomerAMGSetup(coarse_solver,A_seq,F_seq,U_seq);

         hypre_ParAMGDataCoarseSolver(amg_data) = coarse_solver;
         hypre_ParAMGDataACoarse(amg_data) = A_seq;
         hypre_ParAMGDataFCoarse(amg_data) = F_seq;
         hypre_ParAMGDataUCoarse(amg_data) = U_seq;
         hypre_ParAMGDataNewComm(amg_data) = new_comm;
      }
      hypre_TFree(info);
      hypre_TFree(ranks);
   }
 
   return 0;
   
   
}
Exemple #3
0
HYPRE_Int hypre_BlockTridiagSetup(void *data, hypre_ParCSRMatrix *A,
                            hypre_ParVector *b, hypre_ParVector *x) 
{
   HYPRE_Int                i, j, *index_set1, print_level, nsweeps, relax_type;
   HYPRE_Int                nrows, nrows1, nrows2, start1, start2, *index_set2;
   HYPRE_Int                count, ierr;
   double             threshold;
   hypre_ParCSRMatrix **submatrices;
   HYPRE_Solver       precon1;
   HYPRE_Solver       precon2;
   HYPRE_IJVector     ij_u1, ij_u2, ij_f1, ij_f2;
   hypre_ParVector    *vector;
   MPI_Comm           comm;
   hypre_BlockTridiagData *b_data = (hypre_BlockTridiagData *) data;

   HYPRE_ParCSRMatrixGetComm((HYPRE_ParCSRMatrix) A, &comm);
   index_set1 = b_data->index_set1;
   nrows1 = index_set1[0];
   nrows  = hypre_ParCSRMatrixNumRows(A);
   nrows2 = nrows - nrows1;
   b_data->index_set2 = hypre_CTAlloc(HYPRE_Int, nrows2+1);
   index_set2 = b_data->index_set2;
   index_set2[0] = nrows2;
   count = 1;
   for (i = 0; i < index_set1[1]; i++) index_set2[count++] = i;
   for (i = 1; i < nrows1; i++) 
      for (j = index_set1[i]+1; j < index_set1[i+1]; j++) 
         index_set2[count++] = j;
   for (i = index_set1[nrows1]+1; i < nrows; i++) index_set2[count++] = i;

   submatrices = hypre_CTAlloc(hypre_ParCSRMatrix *, 4);
   hypre_ParCSRMatrixExtractSubmatrices(A, index_set1, &submatrices);

   nrows1 = hypre_ParCSRMatrixNumRows(submatrices[0]);
   nrows2 = hypre_ParCSRMatrixNumRows(submatrices[3]); 
   start1 = hypre_ParCSRMatrixFirstRowIndex(submatrices[0]);
   start2 = hypre_ParCSRMatrixFirstRowIndex(submatrices[3]);
   HYPRE_IJVectorCreate(comm, start1, start1+nrows1-1, &ij_u1);
   HYPRE_IJVectorSetObjectType(ij_u1, HYPRE_PARCSR);
   ierr  = HYPRE_IJVectorInitialize(ij_u1);
   ierr += HYPRE_IJVectorAssemble(ij_u1);
   hypre_assert(!ierr);
   HYPRE_IJVectorCreate(comm, start1, start1+nrows1-1, &ij_f1);
   HYPRE_IJVectorSetObjectType(ij_f1, HYPRE_PARCSR);
   ierr  = HYPRE_IJVectorInitialize(ij_f1);
   ierr += HYPRE_IJVectorAssemble(ij_f1);
   hypre_assert(!ierr);
   HYPRE_IJVectorCreate(comm, start2, start2+nrows2-1, &ij_u2);
   HYPRE_IJVectorSetObjectType(ij_u2, HYPRE_PARCSR);
   ierr  = HYPRE_IJVectorInitialize(ij_u2);
   ierr += HYPRE_IJVectorAssemble(ij_u2);
   hypre_assert(!ierr);
   HYPRE_IJVectorCreate(comm, start2, start2+nrows1-1, &ij_f2);
   HYPRE_IJVectorSetObjectType(ij_f2, HYPRE_PARCSR);
   ierr  = HYPRE_IJVectorInitialize(ij_f2);
   ierr += HYPRE_IJVectorAssemble(ij_f2);
   hypre_assert(!ierr);
   HYPRE_IJVectorGetObject(ij_f1, (void **) &vector);
   b_data->F1 = vector;
   HYPRE_IJVectorGetObject(ij_u1, (void **) &vector);
   b_data->U1 = vector;
   HYPRE_IJVectorGetObject(ij_f2, (void **) &vector);
   b_data->F2 = vector;
   HYPRE_IJVectorGetObject(ij_u2, (void **) &vector);
   b_data->U2 = vector;

   print_level = b_data->print_level;
   threshold   = b_data->threshold;
   nsweeps     = b_data->num_sweeps;
   relax_type  = b_data->relax_type;
   threshold = b_data->threshold;
   HYPRE_BoomerAMGCreate(&precon1);
   HYPRE_BoomerAMGSetMaxIter(precon1, 1);
   HYPRE_BoomerAMGSetCycleType(precon1, 1);
   HYPRE_BoomerAMGSetPrintLevel(precon1, print_level);
   HYPRE_BoomerAMGSetMaxLevels(precon1, 25);
   HYPRE_BoomerAMGSetMeasureType(precon1, 0);
   HYPRE_BoomerAMGSetCoarsenType(precon1, 0);
   HYPRE_BoomerAMGSetStrongThreshold(precon1, threshold);
   HYPRE_BoomerAMGSetNumFunctions(precon1, 1);
   HYPRE_BoomerAMGSetNumSweeps(precon1, nsweeps);
   HYPRE_BoomerAMGSetRelaxType(precon1, relax_type);
   hypre_BoomerAMGSetup(precon1, submatrices[0], b_data->U1, b_data->F1);

   HYPRE_BoomerAMGCreate(&precon2);
   HYPRE_BoomerAMGSetMaxIter(precon2, 1);
   HYPRE_BoomerAMGSetCycleType(precon2, 1);
   HYPRE_BoomerAMGSetPrintLevel(precon2, print_level);
   HYPRE_BoomerAMGSetMaxLevels(precon2, 25);
   HYPRE_BoomerAMGSetMeasureType(precon2, 0);
   HYPRE_BoomerAMGSetCoarsenType(precon2, 0);
   HYPRE_BoomerAMGSetMeasureType(precon2, 1);
   HYPRE_BoomerAMGSetStrongThreshold(precon2, threshold);
   HYPRE_BoomerAMGSetNumFunctions(precon2, 1);
   HYPRE_BoomerAMGSetNumSweeps(precon2, nsweeps);
   HYPRE_BoomerAMGSetRelaxType(precon2, relax_type);
   hypre_BoomerAMGSetup(precon2, submatrices[3], NULL, NULL);

   b_data->precon1 = precon1;
   b_data->precon2 = precon2;

   b_data->A11 = submatrices[0];
   hypre_ParCSRMatrixDestroy(submatrices[1]);
   b_data->A21 = submatrices[2];
   b_data->A22 = submatrices[3];

   hypre_TFree(submatrices);
   return (0);
}
Exemple #4
0
 inline void numfact(unsigned int ncol, int* I, int* loc2glob, int* J, K* C) {
     static_assert(std::is_same<double, K>::value, "Hypre only supports double-precision floating-point real numbers");
     static_assert(S == 'G', "Hypre only supports nonsymmetric matrices");
     HYPRE_IJMatrixCreate(DMatrix::_communicator, loc2glob[0], loc2glob[1], loc2glob[0], loc2glob[1], &_A);
     HYPRE_IJMatrixSetObjectType(_A, HYPRE_PARCSR);
     HYPRE_IJMatrixSetRowSizes(_A, I + 1);
     _local = ncol;
     int* rows = new int[3 * _local]();
     int* diag_sizes = rows + _local;
     int* offdiag_sizes = diag_sizes + _local;
     rows[0] = I[0];
     for(unsigned int i = 0; i < _local; ++i) {
         std::for_each(J + rows[0], J + rows[0] + I[i + 1], [&](int& j) { (j < loc2glob[0] || loc2glob[1] < j) ? ++offdiag_sizes[i] : ++diag_sizes[i]; });
         rows[0] += I[i + 1];
     }
     HYPRE_IJMatrixSetDiagOffdSizes(_A, diag_sizes, offdiag_sizes);
     HYPRE_IJMatrixSetMaxOffProcElmts(_A, 0);
     HYPRE_IJMatrixInitialize(_A);
     std::iota(rows, rows + _local, loc2glob[0]);
     HYPRE_IJMatrixSetValues(_A, _local, I + 1, rows, J, C);
     HYPRE_IJMatrixAssemble(_A);
     HYPRE_IJVectorCreate(DMatrix::_communicator, loc2glob[0], loc2glob[1], &_b);
     HYPRE_IJVectorSetObjectType(_b, HYPRE_PARCSR);
     HYPRE_IJVectorInitialize(_b);
     HYPRE_IJVectorCreate(DMatrix::_communicator, loc2glob[0], loc2glob[1], &_x);
     HYPRE_IJVectorSetObjectType(_x, HYPRE_PARCSR);
     HYPRE_IJVectorInitialize(_x);
     delete [] rows;
     delete [] I;
     delete [] loc2glob;
     HYPRE_BoomerAMGCreate(_strategy == 1 ? &_solver : &_precond);
     HYPRE_BoomerAMGSetCoarsenType(_strategy == 1 ? _solver : _precond, 6); /* Falgout coarsening */
     HYPRE_BoomerAMGSetRelaxType(_strategy == 1 ? _solver : _precond, 6);   /* G-S/Jacobi hybrid relaxation */
     HYPRE_BoomerAMGSetNumSweeps(_strategy == 1 ? _solver : _precond, 1);   /* sweeps on each level */
     HYPRE_BoomerAMGSetMaxLevels(_strategy == 1 ? _solver : _precond, 10);  /* maximum number of levels */
     HYPRE_ParCSRMatrix parcsr_A;
     HYPRE_IJMatrixGetObject(_A, reinterpret_cast<void**>(&parcsr_A));
     HYPRE_ParVector par_b;
     HYPRE_IJVectorGetObject(_b, reinterpret_cast<void**>(&par_b));
     HYPRE_ParVector par_x;
     HYPRE_IJVectorGetObject(_x, reinterpret_cast<void**>(&par_x));
     if(_strategy == 1) {
         HYPRE_BoomerAMGSetTol(_solver, 1.0e-8);
         HYPRE_BoomerAMGSetMaxIter(_solver, 1000);
         HYPRE_BoomerAMGSetPrintLevel(_solver, 1);
         HYPRE_BoomerAMGSetup(_solver, parcsr_A, nullptr, nullptr);
     }
     else {
         HYPRE_BoomerAMGSetTol(_precond, 0.0);
         HYPRE_BoomerAMGSetMaxIter(_precond, 1);
         HYPRE_BoomerAMGSetPrintLevel(_precond, 1);
         if(_strategy == 2) {
             HYPRE_ParCSRPCGCreate(DMatrix::_communicator, &_solver);
             HYPRE_PCGSetMaxIter(_solver, 500);
             HYPRE_PCGSetTol(_solver, 1.0e-8);
             HYPRE_PCGSetTwoNorm(_solver, 1);
             HYPRE_PCGSetPrintLevel(_solver, 1);
             HYPRE_PCGSetLogging(_solver, 1);
             HYPRE_PCGSetPrecond(_solver, reinterpret_cast<HYPRE_PtrToSolverFcn>(HYPRE_BoomerAMGSolve), reinterpret_cast<HYPRE_PtrToSolverFcn>(HYPRE_BoomerAMGSetup), _precond);
             HYPRE_ParCSRPCGSetup(_solver, parcsr_A, par_b, par_x);
         }
         else {
             HYPRE_ParCSRFlexGMRESCreate(DMatrix::_communicator, &_solver);
             HYPRE_FlexGMRESSetKDim(_solver, 50);
             HYPRE_FlexGMRESSetMaxIter(_solver, 500);
             HYPRE_FlexGMRESSetTol(_solver, 1.0e-8);
             HYPRE_FlexGMRESSetPrintLevel(_solver, 1);
             HYPRE_FlexGMRESSetLogging(_solver, 1);
             HYPRE_FlexGMRESSetPrecond(_solver, reinterpret_cast<HYPRE_PtrToSolverFcn>(HYPRE_BoomerAMGSolve), reinterpret_cast<HYPRE_PtrToSolverFcn>(HYPRE_BoomerAMGSetup), _precond);
             HYPRE_ParCSRFlexGMRESSetup(_solver, parcsr_A, par_b, par_x);
         }
     }
 }
Exemple #5
0
int main (int argc, char *argv[])
{
   HYPRE_Int i;
   int myid, num_procs;
   int N, n;

   HYPRE_Int ilower, iupper;
   HYPRE_Int local_size, extra;

   int solver_id;
   int print_solution, print_system;

   double h, h2;

   HYPRE_IJMatrix A;
   HYPRE_ParCSRMatrix parcsr_A;
   HYPRE_IJVector b;
   HYPRE_ParVector par_b;
   HYPRE_IJVector x;
   HYPRE_ParVector par_x;

   HYPRE_Solver solver, precond;

   /* Initialize MPI */
   MPI_Init(&argc, &argv);
   MPI_Comm_rank(MPI_COMM_WORLD, &myid);
   MPI_Comm_size(MPI_COMM_WORLD, &num_procs);

   /* Default problem parameters */
   n = 33;
   solver_id = 0;
   print_solution  = 0;
   print_system = 0;


   /* Parse command line */
   {
      int arg_index = 0;
      int print_usage = 0;

      while (arg_index < argc)
      {
         if ( strcmp(argv[arg_index], "-n") == 0 )
         {
            arg_index++;
            n = atoi(argv[arg_index++]);
         }
         else if ( strcmp(argv[arg_index], "-solver") == 0 )
         {
            arg_index++;
            solver_id = atoi(argv[arg_index++]);
         }
         else if ( strcmp(argv[arg_index], "-print_solution") == 0 )
         {
            arg_index++;
            print_solution = 1;
         }
         else if ( strcmp(argv[arg_index], "-print_system") == 0 )
         {
            arg_index++;
            print_system = 1;
         }


         else if ( strcmp(argv[arg_index], "-help") == 0 )
         {
            print_usage = 1;
            break;
         }
         else
         {
            arg_index++;
         }
      }

      if ((print_usage) && (myid == 0))
      {
         printf("\n");
         printf("Usage: %s [<options>]\n", argv[0]);
         printf("\n");
         printf("  -n <n>              : problem size in each direction (default: 33)\n");
         printf("  -solver <ID>        : solver ID\n");
         printf("                        0  - AMG (default) \n");
         printf("                        1  - AMG-PCG\n");
         printf("                        8  - ParaSails-PCG\n");
         printf("                        50 - PCG\n");
         printf("                        61 - AMG-FlexGMRES\n");
         printf("  -print_solution     : print the solution vector\n");
         printf("  -print_system       : print the matrix and rhs\n");
         printf("\n");
      }

      if (print_usage)
      {
         MPI_Finalize();
         return (0);
      }
   }

   /* Preliminaries: want at least one processor per row */
   if (n*n < num_procs) n = sqrt(num_procs) + 1;
   N = n*n; /* global number of rows */
   h = 1.0/(n+1); /* mesh size*/
   h2 = h*h;

   /* Each processor knows only of its own rows - the range is denoted by ilower
      and upper.  Here we partition the rows. We account for the fact that
      N may not divide evenly by the number of processors. */
   local_size = N/num_procs;
   extra = N - local_size*num_procs;

   ilower = local_size*myid;
   ilower += hypre_min(myid, extra);

   iupper = local_size*(myid+1);
   iupper += hypre_min(myid+1, extra);
   iupper = iupper - 1;

   /* How many rows do I have? */
   local_size = iupper - ilower + 1;

   /* Create the matrix.
      Note that this is a square matrix, so we indicate the row partition
      size twice (since number of rows = number of cols) */
   HYPRE_IJMatrixCreate(MPI_COMM_WORLD, ilower, iupper, ilower, iupper, &A);

   /* Choose a parallel csr format storage (see the User's Manual) */
   HYPRE_IJMatrixSetObjectType(A, HYPRE_PARCSR);

   /* Initialize before setting coefficients */
   HYPRE_IJMatrixInitialize(A);

   /* Now go through my local rows and set the matrix entries.
      Each row has at most 5 entries. For example, if n=3:

      A = [M -I 0; -I M -I; 0 -I M]
      M = [4 -1 0; -1 4 -1; 0 -1 4]

      Note that here we are setting one row at a time, though
      one could set all the rows together (see the User's Manual).
   */
   {
      HYPRE_Int nnz;
      double values[5];
      HYPRE_Int cols[5];

      for (i = ilower; i <= iupper; i++)
      {
         nnz = 0;

         /* The left identity block:position i-n */
         if ((i-n)>=0)
         {
            cols[nnz] = i-n;
            values[nnz] = -1.0;
            nnz++;
         }

         /* The left -1: position i-1 */
         if (i%n)
         {
            cols[nnz] = i-1;
            values[nnz] = -1.0;
            nnz++;
         }

         /* Set the diagonal: position i */
         cols[nnz] = i;
         values[nnz] = 4.0;
         nnz++;

         /* The right -1: position i+1 */
         if ((i+1)%n)
         {
            cols[nnz] = i+1;
            values[nnz] = -1.0;
            nnz++;
         }

         /* The right identity block:position i+n */
         if ((i+n)< N)
         {
            cols[nnz] = i+n;
            values[nnz] = -1.0;
            nnz++;
         }

         /* Set the values for row i */
         HYPRE_IJMatrixSetValues(A, 1, &nnz, &i, cols, values);
      }
   }

   /* Assemble after setting the coefficients */
   HYPRE_IJMatrixAssemble(A);

   /* Note: for the testing of small problems, one may wish to read
      in a matrix in IJ format (for the format, see the output files
      from the -print_system option).
      In this case, one would use the following routine:
      HYPRE_IJMatrixRead( <filename>, MPI_COMM_WORLD,
                          HYPRE_PARCSR, &A );
      <filename>  = IJ.A.out to read in what has been printed out
      by -print_system (processor numbers are omitted).
      A call to HYPRE_IJMatrixRead is an *alternative* to the
      following sequence of HYPRE_IJMatrix calls:
      Create, SetObjectType, Initialize, SetValues, and Assemble
   */


   /* Get the parcsr matrix object to use */
   HYPRE_IJMatrixGetObject(A, (void**) &parcsr_A);


   /* Create the rhs and solution */
   HYPRE_IJVectorCreate(MPI_COMM_WORLD, ilower, iupper,&b);
   HYPRE_IJVectorSetObjectType(b, HYPRE_PARCSR);
   HYPRE_IJVectorInitialize(b);

   HYPRE_IJVectorCreate(MPI_COMM_WORLD, ilower, iupper,&x);
   HYPRE_IJVectorSetObjectType(x, HYPRE_PARCSR);
   HYPRE_IJVectorInitialize(x);

   /* Set the rhs values to h^2 and the solution to zero */
   {
      double *rhs_values, *x_values;
      HYPRE_Int *rows;

      rhs_values = calloc(local_size, sizeof(double));
      x_values = calloc(local_size, sizeof(double));
      rows = calloc(local_size, sizeof(HYPRE_Int));

      for (i=0; i<local_size; i++)
      {
         rhs_values[i] = h2;
         x_values[i] = 0.0;
         rows[i] = ilower + i;
      }

      HYPRE_IJVectorSetValues(b, local_size, rows, rhs_values);
      HYPRE_IJVectorSetValues(x, local_size, rows, x_values);

      free(x_values);
      free(rhs_values);
      free(rows);
   }


   HYPRE_IJVectorAssemble(b);
   /*  As with the matrix, for testing purposes, one may wish to read in a rhs:
       HYPRE_IJVectorRead( <filename>, MPI_COMM_WORLD,
                                 HYPRE_PARCSR, &b );
       as an alternative to the
       following sequence of HYPRE_IJVectors calls:
       Create, SetObjectType, Initialize, SetValues, and Assemble
   */
   HYPRE_IJVectorGetObject(b, (void **) &par_b);

   HYPRE_IJVectorAssemble(x);
   HYPRE_IJVectorGetObject(x, (void **) &par_x);


  /*  Print out the system  - files names will be IJ.out.A.XXXXX
       and IJ.out.b.XXXXX, where XXXXX = processor id */
   if (print_system)
   {
      HYPRE_IJMatrixPrint(A, "IJ.out.A");
      HYPRE_IJVectorPrint(b, "IJ.out.b");
   }


   /* Choose a solver and solve the system */

   /* AMG */
   if (solver_id == 0)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
      HYPRE_BoomerAMGCreate(&solver);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_BoomerAMGSetPrintLevel(solver, 3);  /* print solve info + parameters */
      HYPRE_BoomerAMGSetCoarsenType(solver, 6); /* Falgout coarsening */
      HYPRE_BoomerAMGSetRelaxType(solver, 3);   /* G-S/Jacobi hybrid relaxation */
      HYPRE_BoomerAMGSetNumSweeps(solver, 1);   /* Sweeeps on each level */
      HYPRE_BoomerAMGSetMaxLevels(solver, 20);  /* maximum number of levels */
      HYPRE_BoomerAMGSetTol(solver, 1e-7);      /* conv. tolerance */

      /* Now setup and solve! */
      HYPRE_BoomerAMGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_BoomerAMGSolve(solver, parcsr_A, par_b, par_x);

      /* Run info - needed logging turned on */
      HYPRE_BoomerAMGGetNumIterations(solver, &num_iterations);
      HYPRE_BoomerAMGGetFinalRelativeResidualNorm(solver, &final_res_norm);
      if (myid == 0)
      {
         printf("\n");
         printf("Iterations = %lld\n", num_iterations);
         printf("Final Relative Residual Norm = %e\n", final_res_norm);
         printf("\n");
      }

      /* Destroy solver */
      HYPRE_BoomerAMGDestroy(solver);
   }
   /* PCG */
   else if (solver_id == 50)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
      HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, &solver);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* prints out the iteration info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */

      /* Now setup and solve! */
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);

      /* Run info - needed logging turned on */
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
      if (myid == 0)
      {
         printf("\n");
         printf("Iterations = %lld\n", num_iterations);
         printf("Final Relative Residual Norm = %e\n", final_res_norm);
         printf("\n");
      }

      /* Destroy solver */
      HYPRE_ParCSRPCGDestroy(solver);
   }
   /* PCG with AMG preconditioner */
   else if (solver_id == 1)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
      HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, &solver);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* print solve info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */

      /* Now set up the AMG preconditioner and specify any parameters */
      HYPRE_BoomerAMGCreate(&precond);
      HYPRE_BoomerAMGSetPrintLevel(precond, 1); /* print amg solution info */
      HYPRE_BoomerAMGSetCoarsenType(precond, 6);
      HYPRE_BoomerAMGSetRelaxType(precond, 6); /* Sym G.S./Jacobi hybrid */
      HYPRE_BoomerAMGSetNumSweeps(precond, 1);
      HYPRE_BoomerAMGSetTol(precond, 0.0); /* conv. tolerance zero */
      HYPRE_BoomerAMGSetMaxIter(precond, 1); /* do only one iteration! */

      /* Set the PCG preconditioner */
      HYPRE_PCGSetPrecond(solver, (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSetup, precond);

      /* Now setup and solve! */
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);

      /* Run info - needed logging turned on */
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
      if (myid == 0)
      {
         printf("\n");
         printf("Iterations = %lld\n", num_iterations);
         printf("Final Relative Residual Norm = %e\n", final_res_norm);
         printf("\n");
      }

      /* Destroy solver and preconditioner */
      HYPRE_ParCSRPCGDestroy(solver);
      HYPRE_BoomerAMGDestroy(precond);
   }
   /* PCG with Parasails Preconditioner */
   else if (solver_id == 8)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      int      sai_max_levels = 1;
      double   sai_threshold = 0.1;
      double   sai_filter = 0.05;
      int      sai_sym = 1;

      /* Create solver */
      HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, &solver);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* print solve info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */

      /* Now set up the ParaSails preconditioner and specify any parameters */
      HYPRE_ParaSailsCreate(MPI_COMM_WORLD, &precond);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_ParaSailsSetParams(precond, sai_threshold, sai_max_levels);
      HYPRE_ParaSailsSetFilter(precond, sai_filter);
      HYPRE_ParaSailsSetSym(precond, sai_sym);
      HYPRE_ParaSailsSetLogging(precond, 3);

      /* Set the PCG preconditioner */
      HYPRE_PCGSetPrecond(solver, (HYPRE_PtrToSolverFcn) HYPRE_ParaSailsSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_ParaSailsSetup, precond);

      /* Now setup and solve! */
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);


      /* Run info - needed logging turned on */
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
      if (myid == 0)
      {
         printf("\n");
         printf("Iterations = %lld\n", num_iterations);
         printf("Final Relative Residual Norm = %e\n", final_res_norm);
         printf("\n");
      }

      /* Destory solver and preconditioner */
      HYPRE_ParCSRPCGDestroy(solver);
      HYPRE_ParaSailsDestroy(precond);
   }
   /* Flexible GMRES with  AMG Preconditioner */
   else if (solver_id == 61)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;
      int    restart = 30;
      int    modify = 1;


      /* Create solver */
      HYPRE_ParCSRFlexGMRESCreate(MPI_COMM_WORLD, &solver);

      /* Set some parameters (See Reference Manual for more parameters) */
      HYPRE_FlexGMRESSetKDim(solver, restart);
      HYPRE_FlexGMRESSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_FlexGMRESSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_FlexGMRESSetPrintLevel(solver, 2); /* print solve info */
      HYPRE_FlexGMRESSetLogging(solver, 1); /* needed to get run info later */


      /* Now set up the AMG preconditioner and specify any parameters */
      HYPRE_BoomerAMGCreate(&precond);
      HYPRE_BoomerAMGSetPrintLevel(precond, 1); /* print amg solution info */
      HYPRE_BoomerAMGSetCoarsenType(precond, 6);
      HYPRE_BoomerAMGSetRelaxType(precond, 6); /* Sym G.S./Jacobi hybrid */
      HYPRE_BoomerAMGSetNumSweeps(precond, 1);
      HYPRE_BoomerAMGSetTol(precond, 0.0); /* conv. tolerance zero */
      HYPRE_BoomerAMGSetMaxIter(precond, 1); /* do only one iteration! */

      /* Set the FlexGMRES preconditioner */
      HYPRE_FlexGMRESSetPrecond(solver, (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSetup, precond);


      if (modify)
      /* this is an optional call  - if you don't call it, hypre_FlexGMRESModifyPCDefault
         is used - which does nothing.  Otherwise, you can define your own, similar to
         the one used here */
         HYPRE_FlexGMRESSetModifyPC( solver,
                                     (HYPRE_PtrToModifyPCFcn) hypre_FlexGMRESModifyPCAMGExample);


      /* Now setup and solve! */
      HYPRE_ParCSRFlexGMRESSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRFlexGMRESSolve(solver, parcsr_A, par_b, par_x);

      /* Run info - needed logging turned on */
      HYPRE_FlexGMRESGetNumIterations(solver, &num_iterations);
      HYPRE_FlexGMRESGetFinalRelativeResidualNorm(solver, &final_res_norm);
      if (myid == 0)
      {
         printf("\n");
         printf("Iterations = %lld\n", num_iterations);
         printf("Final Relative Residual Norm = %e\n", final_res_norm);
         printf("\n");
      }

      /* Destory solver and preconditioner */
      HYPRE_ParCSRFlexGMRESDestroy(solver);
      HYPRE_BoomerAMGDestroy(precond);

   }
   else
   {
      if (myid ==0) printf("Invalid solver id specified.\n");
   }

   /* Print the solution */
   if (print_solution)
      HYPRE_IJVectorPrint(x, "ij.out.x");

   /* Clean up */
   HYPRE_IJMatrixDestroy(A);
   HYPRE_IJVectorDestroy(b);
   HYPRE_IJVectorDestroy(x);

   /* Finalize MPI*/
   MPI_Finalize();

   return(0);
}
Exemple #6
0
HYPRE_Int hypre_AMESetup(void *esolver)
{
   HYPRE_Int ne, *edge_bc;

   hypre_AMEData *ame_data = esolver;
   hypre_AMSData *ams_data = ame_data -> precond;

   if (ams_data -> beta_is_zero)
   {
      ame_data -> t1 = hypre_ParVectorInDomainOf(ams_data -> G);
      ame_data -> t2 = hypre_ParVectorInDomainOf(ams_data -> G);
   }
   else
   {
      ame_data -> t1 = ams_data -> r1;
      ame_data -> t2 = ams_data -> g1;
   }
   ame_data -> t3 = ams_data -> r0;

   /* Eliminate boundary conditions in G = [Gii, Gib; 0, Gbb], i.e.,
      compute [Gii, 0; 0, 0] */
   {
      HYPRE_Int i, j, k, nv;
      HYPRE_Int *offd_edge_bc;

      hypre_ParCSRMatrix *Gt;

      nv = hypre_ParCSRMatrixNumCols(ams_data -> G);
      ne = hypre_ParCSRMatrixNumRows(ams_data -> G);

      edge_bc = hypre_TAlloc(HYPRE_Int, ne);
      for (i = 0; i < ne; i++)
         edge_bc[i] = 0;

      /* Find boundary (eliminated) edges */
      {
         hypre_CSRMatrix *Ad = hypre_ParCSRMatrixDiag(ams_data -> A);
         HYPRE_Int *AdI = hypre_CSRMatrixI(Ad);
         HYPRE_Int *AdJ = hypre_CSRMatrixJ(Ad);
         HYPRE_Real *AdA = hypre_CSRMatrixData(Ad);
         hypre_CSRMatrix *Ao = hypre_ParCSRMatrixOffd(ams_data -> A);
         HYPRE_Int *AoI = hypre_CSRMatrixI(Ao);
         HYPRE_Real *AoA = hypre_CSRMatrixData(Ao);
         HYPRE_Real l1_norm;

         /* A row (edge) is boundary if its off-diag l1 norm is less than eps */
         HYPRE_Real eps = DBL_EPSILON * 1e+4;

         for (i = 0; i < ne; i++)
         {
            l1_norm = 0.0;
            for (j = AdI[i]; j < AdI[i+1]; j++)
               if (AdJ[j] != i)
                  l1_norm += fabs(AdA[j]);
            if (AoI)
               for (j = AoI[i]; j < AoI[i+1]; j++)
                  l1_norm += fabs(AoA[j]);
            if (l1_norm < eps)
               edge_bc[i] = 1;
         }
      }

      hypre_ParCSRMatrixTranspose(ams_data -> G, &Gt, 1);

      /* Use a Matvec communication to find which of the edges
         connected to local vertices are on the boundary */
      {
         hypre_ParCSRCommHandle *comm_handle;
         hypre_ParCSRCommPkg *comm_pkg;
         HYPRE_Int num_sends, *int_buf_data;
         HYPRE_Int index, start;

         offd_edge_bc = hypre_CTAlloc(HYPRE_Int, hypre_CSRMatrixNumCols(hypre_ParCSRMatrixOffd(Gt)));

         hypre_MatvecCommPkgCreate(Gt);
         comm_pkg = hypre_ParCSRMatrixCommPkg(Gt);

         num_sends = hypre_ParCSRCommPkgNumSends(comm_pkg);
         int_buf_data = hypre_CTAlloc(HYPRE_Int,
                                      hypre_ParCSRCommPkgSendMapStart(comm_pkg,
                                                                      num_sends));
         index = 0;
         for (i = 0; i < num_sends; i++)
         {
            start = hypre_ParCSRCommPkgSendMapStart(comm_pkg, i);
            for (j = start; j < hypre_ParCSRCommPkgSendMapStart(comm_pkg, i+1); j++)
            {
               k = hypre_ParCSRCommPkgSendMapElmt(comm_pkg,j);
               int_buf_data[index++] = edge_bc[k];
            }
         }
         comm_handle = hypre_ParCSRCommHandleCreate(11, comm_pkg,
                                                    int_buf_data, offd_edge_bc);
         hypre_ParCSRCommHandleDestroy(comm_handle);
         hypre_TFree(int_buf_data);
      }

      /* Eliminate boundary vertex entries in G^t */
      {
         hypre_CSRMatrix *Gtd = hypre_ParCSRMatrixDiag(Gt);
         HYPRE_Int *GtdI = hypre_CSRMatrixI(Gtd);
         HYPRE_Int *GtdJ = hypre_CSRMatrixJ(Gtd);
         HYPRE_Real *GtdA = hypre_CSRMatrixData(Gtd);
         hypre_CSRMatrix *Gto = hypre_ParCSRMatrixOffd(Gt);
         HYPRE_Int *GtoI = hypre_CSRMatrixI(Gto);
         HYPRE_Int *GtoJ = hypre_CSRMatrixJ(Gto);
         HYPRE_Real *GtoA = hypre_CSRMatrixData(Gto);

         HYPRE_Int bdr;

         for (i = 0; i < nv; i++)
         {
            bdr = 0;
            /* A vertex is boundary if it belongs to a boundary edge */
            for (j = GtdI[i]; j < GtdI[i+1]; j++)
               if (edge_bc[GtdJ[j]]) { bdr = 1; break; }
            if (!bdr && GtoI)
               for (j = GtoI[i]; j < GtoI[i+1]; j++)
                  if (offd_edge_bc[GtoJ[j]]) { bdr = 1; break; }

            if (bdr)
            {
               for (j = GtdI[i]; j < GtdI[i+1]; j++)
                  /* if (!edge_bc[GtdJ[j]]) */
                  GtdA[j] = 0.0;
               if (GtoI)
                  for (j = GtoI[i]; j < GtoI[i+1]; j++)
                     /* if (!offd_edge_bc[GtoJ[j]]) */
                     GtoA[j] = 0.0;
            }
         }
      }

      hypre_ParCSRMatrixTranspose(Gt, &ame_data -> G, 1);

      hypre_ParCSRMatrixDestroy(Gt);
      hypre_TFree(offd_edge_bc);
   }

   /* Compute G^t M G */
   {
      if (!hypre_ParCSRMatrixCommPkg(ame_data -> G))
         hypre_MatvecCommPkgCreate(ame_data -> G);

      if (!hypre_ParCSRMatrixCommPkg(ame_data -> M))
         hypre_MatvecCommPkgCreate(ame_data -> M);

      hypre_BoomerAMGBuildCoarseOperator(ame_data -> G,
                                         ame_data -> M,
                                         ame_data -> G,
                                         &ame_data -> A_G);

      hypre_ParCSRMatrixFixZeroRows(ame_data -> A_G);
   }

   /* Create AMG preconditioner and PCG-AMG solver for G^tMG */
   {
      HYPRE_BoomerAMGCreate(&ame_data -> B1_G);
      HYPRE_BoomerAMGSetCoarsenType(ame_data -> B1_G, ams_data -> B_G_coarsen_type);
      HYPRE_BoomerAMGSetAggNumLevels(ame_data -> B1_G, ams_data -> B_G_agg_levels);
      HYPRE_BoomerAMGSetRelaxType(ame_data -> B1_G, ams_data -> B_G_relax_type);
      HYPRE_BoomerAMGSetNumSweeps(ame_data -> B1_G, 1);
      HYPRE_BoomerAMGSetMaxLevels(ame_data -> B1_G, 25);
      HYPRE_BoomerAMGSetTol(ame_data -> B1_G, 0.0);
      HYPRE_BoomerAMGSetMaxIter(ame_data -> B1_G, 1);
      HYPRE_BoomerAMGSetStrongThreshold(ame_data -> B1_G, ams_data -> B_G_theta);
      /* don't use exact solve on the coarsest level (matrix may be singular) */
      HYPRE_BoomerAMGSetCycleRelaxType(ame_data -> B1_G,
                                       ams_data -> B_G_relax_type,
                                       3);

      HYPRE_ParCSRPCGCreate(hypre_ParCSRMatrixComm(ame_data->A_G),
                            &ame_data -> B2_G);
      HYPRE_PCGSetPrintLevel(ame_data -> B2_G, 0);
      HYPRE_PCGSetTol(ame_data -> B2_G, 1e-12);
      HYPRE_PCGSetMaxIter(ame_data -> B2_G, 20);

      HYPRE_PCGSetPrecond(ame_data -> B2_G,
                          (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSetup,
                          ame_data -> B1_G);

      HYPRE_ParCSRPCGSetup(ame_data -> B2_G,
                           (HYPRE_ParCSRMatrix)ame_data->A_G,
                           (HYPRE_ParVector)ame_data->t1,
                           (HYPRE_ParVector)ame_data->t2);
   }

   /* Setup LOBPCG */
   {
      HYPRE_Int seed = 75;
      mv_InterfaceInterpreter* interpreter;
      mv_MultiVectorPtr eigenvectors;

      ame_data -> interpreter = hypre_CTAlloc(mv_InterfaceInterpreter,1);
      interpreter = (mv_InterfaceInterpreter*) ame_data -> interpreter;
      HYPRE_ParCSRSetupInterpreter(interpreter);

      ame_data -> eigenvalues = hypre_CTAlloc(HYPRE_Real, ame_data -> block_size);

      ame_data -> eigenvectors =
         mv_MultiVectorCreateFromSampleVector(interpreter,
                                              ame_data -> block_size,
                                              ame_data -> t3);
      eigenvectors = (mv_MultiVectorPtr) ame_data -> eigenvectors;

      mv_MultiVectorSetRandom (eigenvectors, seed);

      /* Make the initial vectors discretely divergence free */
      {
         HYPRE_Int i, j;
         HYPRE_Real *data;

         mv_TempMultiVector* tmp = mv_MultiVectorGetData(eigenvectors);
         HYPRE_ParVector *v = (HYPRE_ParVector*)(tmp -> vector);
         hypre_ParVector *vi;

         for (i = 0; i < ame_data -> block_size; i++)
         {
            vi = (hypre_ParVector*) v[i];
            data = hypre_VectorData(hypre_ParVectorLocalVector(vi));
            for (j = 0; j < ne; j++)
               if (edge_bc[j])
                  data[j] = 0.0;
            hypre_AMEDiscrDivFreeComponent(esolver, vi);
         }
      }
   }

   hypre_TFree(edge_bc);

   return hypre_error_flag;
}
HYPRE_Int main (HYPRE_Int argc, char *argv[])
{
   HYPRE_Int i;
   HYPRE_Int myid, num_procs;
   HYPRE_Int N, n;

   HYPRE_Int ilower, iupper;
   HYPRE_Int local_size, extra;

   HYPRE_Int solver_id;
   HYPRE_Int print_solution;

   double h, h2;

#ifdef HYPRE_FORTRAN
   hypre_F90_Obj A;
   hypre_F90_Obj parcsr_A;
   hypre_F90_Obj b;
   hypre_F90_Obj par_b;
   hypre_F90_Obj x;
   hypre_F90_Obj par_x;

   hypre_F90_Obj solver, precond;

   hypre_F90_Obj long_temp_COMM;
        HYPRE_Int temp_COMM;
        HYPRE_Int precond_id;

        HYPRE_Int one = 1;
        HYPRE_Int two = 2;
        HYPRE_Int three = 3;
        HYPRE_Int six = 6;
        HYPRE_Int twenty = 20;
        HYPRE_Int thousand = 1000;
        HYPRE_Int hypre_type = HYPRE_PARCSR;

     double oo1 = 1.e-3;
     double tol = 1.e-7;
#else
   HYPRE_IJMatrix A;
   HYPRE_ParCSRMatrix parcsr_A;
   HYPRE_IJVector b;
   HYPRE_ParVector par_b;
   HYPRE_IJVector x;
   HYPRE_ParVector par_x;

   HYPRE_Solver solver, precond;
#endif

   /* Initialize MPI */
   hypre_MPI_Init(&argc, &argv);
   hypre_MPI_Comm_rank(hypre_MPI_COMM_WORLD, &myid);
   hypre_MPI_Comm_size(hypre_MPI_COMM_WORLD, &num_procs);

   /* Default problem parameters */
   n = 33;
   solver_id = 0;
   print_solution  = 0;

   /* Parse command line */
   {
      HYPRE_Int arg_index = 0;
      HYPRE_Int print_usage = 0;

      while (arg_index < argc)
      {
         if ( strcmp(argv[arg_index], "-n") == 0 )
         {
            arg_index++;
            n = atoi(argv[arg_index++]);
         }
         else if ( strcmp(argv[arg_index], "-solver") == 0 )
         {
            arg_index++;
            solver_id = atoi(argv[arg_index++]);
         }
         else if ( strcmp(argv[arg_index], "-print_solution") == 0 )
         {
            arg_index++;
            print_solution = 1;
         }
         else if ( strcmp(argv[arg_index], "-help") == 0 )
         {
            print_usage = 1;
            break;
         }
         else
         {
            arg_index++;
         }
      }

      if ((print_usage) && (myid == 0))
      {
         hypre_printf("\n");
         hypre_printf("Usage: %s [<options>]\n", argv[0]);
         hypre_printf("\n");
         hypre_printf("  -n <n>              : problem size in each direction (default: 33)\n");
         hypre_printf("  -solver <ID>        : solver ID\n");
         hypre_printf("                        0  - AMG (default) \n");
         hypre_printf("                        1  - AMG-PCG\n");
         hypre_printf("                        8  - ParaSails-PCG\n");
         hypre_printf("                        50 - PCG\n");
         hypre_printf("  -print_solution     : print the solution vector\n");
         hypre_printf("\n");
      }

      if (print_usage)
      {
         hypre_MPI_Finalize();
         return (0);
      }
   }

   /* Preliminaries: want at least one processor per row */
   if (n*n < num_procs) n = sqrt(num_procs) + 1;
   N = n*n; /* global number of rows */
   h = 1.0/(n+1); /* mesh size*/
   h2 = h*h;

   /* Each processor knows only of its own rows - the range is denoted by ilower
      and upper.  Here we partition the rows. We account for the fact that
      N may not divide evenly by the number of processors. */
   local_size = N/num_procs;
   extra = N - local_size*num_procs;

   ilower = local_size*myid;
   ilower += hypre_min(myid, extra);

   iupper = local_size*(myid+1);
   iupper += hypre_min(myid+1, extra);
   iupper = iupper - 1;

   /* How many rows do I have? */
   local_size = iupper - ilower + 1;

   /* Create the matrix.
      Note that this is a square matrix, so we indicate the row partition
      size twice (since number of rows = number of cols) */
#ifdef HYPRE_FORTRAN
   long_temp_COMM = (hypre_F90_Obj) hypre_MPI_COMM_WORLD;
   temp_COMM = (HYPRE_Int) hypre_MPI_COMM_WORLD;
   HYPRE_IJMatrixCreate(&long_temp_COMM, &ilower, &iupper, &ilower, &iupper, &A);
#else
   HYPRE_IJMatrixCreate(hypre_MPI_COMM_WORLD, ilower, iupper, ilower, iupper, &A);
#endif

   /* Choose a parallel csr format storage (see the User's Manual) */
#ifdef HYPRE_FORTRAN
   HYPRE_IJMatrixSetObjectType(&A, &hypre_type);
#else
   HYPRE_IJMatrixSetObjectType(A, HYPRE_PARCSR);
#endif

   /* Initialize before setting coefficients */
#ifdef HYPRE_FORTRAN
   HYPRE_IJMatrixInitialize(&A);
#else
   HYPRE_IJMatrixInitialize(A);
#endif

   /* Now go through my local rows and set the matrix entries.
      Each row has at most 5 entries. For example, if n=3:

      A = [M -I 0; -I M -I; 0 -I M]
      M = [4 -1 0; -1 4 -1; 0 -1 4]

      Note that here we are setting one row at a time, though
      one could set all the rows together (see the User's Manual).
   */
   {
      HYPRE_Int nnz;
      double values[5];
      HYPRE_Int cols[5];

      for (i = ilower; i <= iupper; i++)
      {
         nnz = 0;

         /* The left identity block:position i-n */
         if ((i-n)>=0)
         {
	    cols[nnz] = i-n;
	    values[nnz] = -1.0;
	    nnz++;
         }

         /* The left -1: position i-1 */
         if (i%n)
         {
            cols[nnz] = i-1;
            values[nnz] = -1.0;
            nnz++;
         }

         /* Set the diagonal: position i */
         cols[nnz] = i;
         values[nnz] = 4.0;
         nnz++;

         /* The right -1: position i+1 */
         if ((i+1)%n)
         {
            cols[nnz] = i+1;
            values[nnz] = -1.0;
            nnz++;
         }

         /* The right identity block:position i+n */
         if ((i+n)< N)
         {
            cols[nnz] = i+n;
            values[nnz] = -1.0;
            nnz++;
         }

         /* Set the values for row i */
#ifdef HYPRE_FORTRAN
         HYPRE_IJMatrixSetValues(&A, &one, &nnz, &i, &cols[0], &values[0]);
#else
         HYPRE_IJMatrixSetValues(A, 1, &nnz, &i, cols, values);
#endif
      }
   }

   /* Assemble after setting the coefficients */
#ifdef HYPRE_FORTRAN
   HYPRE_IJMatrixAssemble(&A);
#else
   HYPRE_IJMatrixAssemble(A);
#endif
   /* Get the parcsr matrix object to use */
#ifdef HYPRE_FORTRAN
   HYPRE_IJMatrixGetObject(&A, &parcsr_A);
   HYPRE_IJMatrixGetObject(&A, &parcsr_A);
#else
   HYPRE_IJMatrixGetObject(A, (void**) &parcsr_A);
   HYPRE_IJMatrixGetObject(A, (void**) &parcsr_A);
#endif

   /* Create the rhs and solution */
#ifdef HYPRE_FORTRAN
   HYPRE_IJVectorCreate(&temp_COMM, &ilower, &iupper, &b);
   HYPRE_IJVectorSetObjectType(&b, &hypre_type);
   HYPRE_IJVectorInitialize(&b);
#else
   HYPRE_IJVectorCreate(hypre_MPI_COMM_WORLD, ilower, iupper,&b);
   HYPRE_IJVectorSetObjectType(b, HYPRE_PARCSR);
   HYPRE_IJVectorInitialize(b);
#endif

#ifdef HYPRE_FORTRAN
   HYPRE_IJVectorCreate(&temp_COMM, &ilower, &iupper, &x);
   HYPRE_IJVectorSetObjectType(&x, &hypre_type);
   HYPRE_IJVectorInitialize(&x);
#else
   HYPRE_IJVectorCreate(hypre_MPI_COMM_WORLD, ilower, iupper,&x);
   HYPRE_IJVectorSetObjectType(x, HYPRE_PARCSR);
   HYPRE_IJVectorInitialize(x);
#endif

   /* Set the rhs values to h^2 and the solution to zero */
   {
      double *rhs_values, *x_values;
      HYPRE_Int    *rows;

      rhs_values = calloc(local_size, sizeof(double));
      x_values = calloc(local_size, sizeof(double));
      rows = calloc(local_size, sizeof(HYPRE_Int));

      for (i=0; i<local_size; i++)
      {
         rhs_values[i] = h2;
         x_values[i] = 0.0;
         rows[i] = ilower + i;
      }
#ifdef HYPRE_FORTRAN
      HYPRE_IJVectorSetValues(&b, &local_size, &rows[0], &rhs_values[0]);
      HYPRE_IJVectorSetValues(&x, &local_size, &rows[0], &x_values[0]);
#else
      HYPRE_IJVectorSetValues(b, local_size, rows, rhs_values);
      HYPRE_IJVectorSetValues(x, local_size, rows, x_values);
#endif

      free(x_values);
      free(rhs_values);
      free(rows);
   }

#ifdef HYPRE_FORTRAN
   HYPRE_IJVectorAssemble(&b);
   HYPRE_IJVectorGetObject(&b, &par_b);
#else
   HYPRE_IJVectorAssemble(b);
   HYPRE_IJVectorGetObject(b, (void **) &par_b);
#endif

#ifdef HYPRE_FORTRAN
   HYPRE_IJVectorAssemble(&x);
   HYPRE_IJVectorGetObject(&x, &par_x);
#else
   HYPRE_IJVectorAssemble(x);
   HYPRE_IJVectorGetObject(x, (void **) &par_x);
#endif

   /* Choose a solver and solve the system */

   /* AMG */
   if (solver_id == 0)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGCreate(&solver);
#else
      HYPRE_BoomerAMGCreate(&solver);
#endif

      /* Set some parameters (See Reference Manual for more parameters) */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGSetPrintLevel(&solver, &three);  /* print solve info + parameters */
      HYPRE_BoomerAMGSetCoarsenType(&solver, &six); /* Falgout coarsening */
      HYPRE_BoomerAMGSetRelaxType(&solver, &three);   /* G-S/Jacobi hybrid relaxation */
      HYPRE_BoomerAMGSetNumSweeps(&solver, &one);   /* Sweeeps on each level */
      HYPRE_BoomerAMGSetMaxLevels(&solver, &twenty);  /* maximum number of levels */
      HYPRE_BoomerAMGSetTol(&solver, &tol);      /* conv. tolerance */
#else
      HYPRE_BoomerAMGSetPrintLevel(solver, 3);  /* print solve info + parameters */
      HYPRE_BoomerAMGSetCoarsenType(solver, 6); /* Falgout coarsening */
      HYPRE_BoomerAMGSetRelaxType(solver, 3);   /* G-S/Jacobi hybrid relaxation */
      HYPRE_BoomerAMGSetNumSweeps(solver, 1);   /* Sweeeps on each level */
      HYPRE_BoomerAMGSetMaxLevels(solver, 20);  /* maximum number of levels */
      HYPRE_BoomerAMGSetTol(solver, 1e-7);      /* conv. tolerance */
#endif

      /* Now setup and solve! */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGSetup(&solver, &parcsr_A, &par_b, &par_x);
      HYPRE_BoomerAMGSolve(&solver, &parcsr_A, &par_b, &par_x);
#else
      HYPRE_BoomerAMGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_BoomerAMGSolve(solver, parcsr_A, par_b, par_x);
#endif

      /* Run info - needed logging turned on */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGGetNumIterations(&solver, &num_iterations);
      HYPRE_BoomerAMGGetFinalRelativeResidualNorm(&solver, &final_res_norm);
#else
      HYPRE_BoomerAMGGetNumIterations(solver, &num_iterations);
      HYPRE_BoomerAMGGetFinalRelativeResidualNorm(solver, &final_res_norm);
#endif
      if (myid == 0)
      {
         hypre_printf("\n");
         hypre_printf("Iterations = %d\n", num_iterations);
         hypre_printf("Final Relative Residual Norm = %e\n", final_res_norm);
         hypre_printf("\n");
      }

      /* Destroy solver */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGDestroy(&solver);
#else
      HYPRE_BoomerAMGDestroy(solver);
#endif
   }
   /* PCG */
   else if (solver_id == 50)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGCreate(&temp_COMM, &solver);
#else
      HYPRE_ParCSRPCGCreate(hypre_MPI_COMM_WORLD, &solver);
#endif

      /* Set some parameters (See Reference Manual for more parameters) */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetMaxIter(&solver, &thousand); /* max iterations */
      HYPRE_ParCSRPCGSetTol(&solver, &tol); /* conv. tolerance */
      HYPRE_ParCSRPCGSetTwoNorm(&solver, &one); /* use the two norm as the stopping criteria */
      HYPRE_ParCSRPCGSetPrintLevel(&solver, &two); /* prints out the iteration info */
#else
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* prints out the iteration info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */
#endif

      /* Now setup and solve! */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetup(&solver, &parcsr_A, &par_b, &par_x);
      HYPRE_ParCSRPCGSolve(&solver, &parcsr_A, &par_b, &par_x);
#else
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);
#endif

      /* Run info - needed logging turned on */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGGetNumIterations(&solver, &num_iterations);
      HYPRE_ParCSRPCGGetFinalRelativeResidualNorm(&solver, &final_res_norm);
#else
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
#endif
      if (myid == 0)
      {
         hypre_printf("\n");
         hypre_printf("Iterations = %d\n", num_iterations);
         hypre_printf("Final Relative Residual Norm = %e\n", final_res_norm);
         hypre_printf("\n");
      }

      /* Destroy solver */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGDestroy(&solver);
#else
      HYPRE_ParCSRPCGDestroy(solver);
#endif
   }
   /* PCG with AMG preconditioner */
   else if (solver_id == 1)
   {
      HYPRE_Int num_iterations;
      double final_res_norm;

      /* Create solver */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGCreate(&temp_COMM, &solver);
#else
      HYPRE_ParCSRPCGCreate(hypre_MPI_COMM_WORLD, &solver);
#endif

      /* Set some parameters (See Reference Manual for more parameters) */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetMaxIter(&solver, &thousand); /* max iterations */
      HYPRE_ParCSRPCGSetTol(&solver, &tol); /* conv. tolerance */
      HYPRE_ParCSRPCGSetTwoNorm(&solver, &one); /* use the two norm as the stopping criteria */
      HYPRE_ParCSRPCGSetPrintLevel(&solver, &two); /* print solve info */
#else
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* print solve info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */
#endif

      /* Now set up the AMG preconditioner and specify any parameters */
#ifdef HYPRE_FORTRAN
      HYPRE_BoomerAMGCreate(&precond);
      HYPRE_BoomerAMGSetPrintLevel(&precond, &one); /* print amg solution info*/
      HYPRE_BoomerAMGSetCoarsenType(&precond, &six);
      HYPRE_BoomerAMGSetRelaxType(&precond, &three);
      HYPRE_BoomerAMGSetNumSweeps(&precond, &one);
      HYPRE_BoomerAMGSetTol(&precond, &oo1);
#else
      HYPRE_BoomerAMGCreate(&precond);
      HYPRE_BoomerAMGSetPrintLevel(precond, 1); /* print amg solution info*/
      HYPRE_BoomerAMGSetCoarsenType(precond, 6);
      HYPRE_BoomerAMGSetRelaxType(precond, 3);
      HYPRE_BoomerAMGSetNumSweeps(precond, 1);
      HYPRE_BoomerAMGSetTol(precond, 1e-3);
#endif

      /* Set the PCG preconditioner */
#ifdef HYPRE_FORTRAN
      precond_id = 2;
      HYPRE_ParCSRPCGSetPrecond(&solver, &precond_id, &precond);
#else
      HYPRE_PCGSetPrecond(solver, (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_BoomerAMGSetup, precond);
#endif

      /* Now setup and solve! */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetup(&solver, &parcsr_A, &par_b, &par_x);
      HYPRE_ParCSRPCGSolve(&solver, &parcsr_A, &par_b, &par_x);
#else
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);
#endif

      /* Run info - needed logging turned on */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGGetNumIterations(&solver, &num_iterations);
      HYPRE_ParCSRPCGGetFinalRelativeResidualNorm(&solver, &final_res_norm);
#else
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
#endif
      if (myid == 0)
      {
         hypre_printf("\n");
         hypre_printf("Iterations = %d\n", num_iterations);
         hypre_printf("Final Relative Residual Norm = %e\n", final_res_norm);
         hypre_printf("\n");
      }

      /* Destroy solver and preconditioner */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGDestroy(&solver);
      HYPRE_BoomerAMGDestroy(&precond);
#else
      HYPRE_ParCSRPCGDestroy(solver);
      HYPRE_BoomerAMGDestroy(precond);
#endif
   }
   /* PCG with Parasails Preconditioner */
   else if (solver_id == 8)
   {
      HYPRE_Int    num_iterations;
      double final_res_norm;

      HYPRE_Int      sai_max_levels = 1;
      double   sai_threshold = 0.1;
      double   sai_filter = 0.05;
      HYPRE_Int      sai_sym = 1;

      /* Create solver */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGCreate(&temp_COMM, &solver);
#else
      HYPRE_ParCSRPCGCreate(hypre_MPI_COMM_WORLD, &solver);
#endif

      /* Set some parameters (See Reference Manual for more parameters) */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetMaxIter(&solver, &thousand); /* max iterations */
      HYPRE_ParCSRPCGSetTol(&solver, &tol); /* conv. tolerance */
      HYPRE_ParCSRPCGSetTwoNorm(&solver, &one); /* use the two norm as the stopping criteria */
      HYPRE_ParCSRPCGSetPrintLevel(&solver, &two); /* print solve info */
#else
      HYPRE_PCGSetMaxIter(solver, 1000); /* max iterations */
      HYPRE_PCGSetTol(solver, 1e-7); /* conv. tolerance */
      HYPRE_PCGSetTwoNorm(solver, 1); /* use the two norm as the stopping criteria */
      HYPRE_PCGSetPrintLevel(solver, 2); /* print solve info */
      HYPRE_PCGSetLogging(solver, 1); /* needed to get run info later */
#endif

      /* Now set up the ParaSails preconditioner and specify any parameters */
#ifdef HYPRE_FORTRAN
      HYPRE_ParaSailsCreate(&temp_COMM, &precond);
#else
      HYPRE_ParaSailsCreate(hypre_MPI_COMM_WORLD, &precond);
#endif

      /* Set some parameters (See Reference Manual for more parameters) */
#ifdef HYPRE_FORTRAN
      HYPRE_ParaSailsSetParams(&precond, &sai_threshold, &sai_max_levels);
      HYPRE_ParaSailsSetFilter(&precond, &sai_filter);
      HYPRE_ParaSailsSetSym(&precond, &sai_sym);
      HYPRE_ParaSailsSetLogging(&precond, &three);
#else
      HYPRE_ParaSailsSetParams(precond, sai_threshold, sai_max_levels);
      HYPRE_ParaSailsSetFilter(precond, sai_filter);
      HYPRE_ParaSailsSetSym(precond, sai_sym);
      HYPRE_ParaSailsSetLogging(precond, 3);
#endif

      /* Set the PCG preconditioner */
#ifdef HYPRE_FORTRAN
      precond_id = 4;
      HYPRE_ParCSRPCGSetPrecond(&solver, &precond_id, &precond);
#else
      HYPRE_PCGSetPrecond(solver, (HYPRE_PtrToSolverFcn) HYPRE_ParaSailsSolve,
                          (HYPRE_PtrToSolverFcn) HYPRE_ParaSailsSetup, precond);
#endif

      /* Now setup and solve! */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGSetup(&solver, &parcsr_A, &par_b, &par_x);
      HYPRE_ParCSRPCGSolve(&solver, &parcsr_A, &par_b, &par_x);
#else
      HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b, par_x);
      HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b, par_x);
#endif


      /* Run info - needed logging turned on */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGGetNumIterations(&solver, &num_iterations);
      HYPRE_ParCSRPCGGetFinalRelativeResidualNorm(&solver, &final_res_norm);
#else
      HYPRE_PCGGetNumIterations(solver, &num_iterations);
      HYPRE_PCGGetFinalRelativeResidualNorm(solver, &final_res_norm);
#endif
      if (myid == 0)
      {
         hypre_printf("\n");
         hypre_printf("Iterations = %d\n", num_iterations);
         hypre_printf("Final Relative Residual Norm = %e\n", final_res_norm);
         hypre_printf("\n");
      }

      /* Destory solver and preconditioner */
#ifdef HYPRE_FORTRAN
      HYPRE_ParCSRPCGDestroy(&solver);
      HYPRE_ParaSailsDestroy(&precond);
#else
      HYPRE_ParCSRPCGDestroy(solver);
      HYPRE_ParaSailsDestroy(precond);
#endif
   }
   else
   {
      if (myid ==0) hypre_printf("Invalid solver id specified.\n");
   }

   /* Print the solution */
#ifdef HYPRE_FORTRAN
   if (print_solution)
      HYPRE_IJVectorPrint(&x, "ij.out.x");
#else
   if (print_solution)
      HYPRE_IJVectorPrint(x, "ij.out.x");
#endif

   /* Clean up */
#ifdef HYPRE_FORTRAN
   HYPRE_IJMatrixDestroy(&A);
   HYPRE_IJVectorDestroy(&b);
   HYPRE_IJVectorDestroy(&x);
#else
   HYPRE_IJMatrixDestroy(A);
   HYPRE_IJVectorDestroy(b);
   HYPRE_IJVectorDestroy(x);
#endif

   /* Finalize MPI*/
   hypre_MPI_Finalize();

   return(0);
}
int main(int argc, char *argv[]) {
  // printf("start\n");
  int i, j, pi, pj;
  int myid, num_procs;
  int Nx, Ny, nx, ny;
  //nx and ny are number of mesh cells
  int solver_id;
  int vis;
  int ilower[2], iupper[2];
  int nparts = 1;
  int part = 0;

  double hx, hy;

  HYPRE_SStructGraph graph;
  HYPRE_SStructGrid grid;
  HYPRE_SStructStencil stencil;
  HYPRE_SStructMatrix A;
  HYPRE_ParCSRMatrix parcsr_A;
  HYPRE_SStructVector b;
  HYPRE_ParVector par_b;
  HYPRE_SStructVector x;
  HYPRE_ParVector par_x;

  HYPRE_Solver solver;
  // printf("variables initialized\n");
   
  //Initialize MPI
  MPI_Init(&argc, &argv);
  MPI_Comm_rank(MPI_COMM_WORLD, &myid);
  MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
  // printf("mpi initialized\n");
   
  // Set default problem parameters
  nx = 100;
  ny = 100;
  Nx = 1;
  solver_id = 0;
  vis = 0;
  // printf("defaults set\n");
   
  // Parse command line

  int arg_index = 0;

  while (arg_index < argc) {
    if (strcmp(argv[arg_index], "-nx") == 0) {
      arg_index++;
      nx = atoi(argv[arg_index++]);
      // printf("nx set\n");
    } else if (strcmp(argv[arg_index], "-ny") == 0) {
      arg_index++;
      ny = atoi(argv[arg_index++]);
      // printf("ny set\n");
    } else if (strcmp(argv[arg_index], "-Nx") == 0) {
      arg_index++;
      Nx = atoi(argv[arg_index++]);
      // printf("Nx set\n");
    } else if (strcmp(argv[arg_index], "-solver") == 0) {
      arg_index++;
      solver_id = atoi(argv[arg_index++]);
      // printf("solver set\n");
    } else if (strcmp(argv[arg_index], "-vis") == 0) {
      arg_index++;
      vis = 1;
      // printf("print solution\n");
    } else {
      arg_index++;
      // printf("plus plus\n");
    }
  }

  // printf("command line parsed\n");
   
  // Set up processors in grid 
  Ny = num_procs / Nx;
  hx = 1.0 / (Nx * nx);
  hy = 1.0 / (Ny * ny);

  if (Ny <= Nx) {
    pj = myid / Nx;
    pi = myid - pj * Ny;
  } else {
    pi = myid / Ny;
    pj = myid - pi * Nx;
  }
  // printf("processors assigned\n");

  // Determine each processor's piece of the grid 
  ilower[0] = pi * nx;
  ilower[1] = pj * ny;

  iupper[0] = ilower[0] + nx - 1;
  iupper[1] = ilower[1] + ny - 1;

  // printf("upper and lowers assigned\n");
  HYPRE_SStructGridCreate(MPI_COMM_WORLD, 2, nparts, &grid);
  // printf("grid created\n");
  HYPRE_SStructGridSetExtents(grid, part, ilower, iupper);
  // printf("grid set\n");
  
  int nvars = 1;

  HYPRE_SStructVariable vartypes[1] = { HYPRE_SSTRUCT_VARIABLE_CELL };
  // printf("variable type set\n");
  for (i = 0; i < nparts; i++) {
    HYPRE_SStructGridSetVariables(grid, i, nvars, vartypes);
  }
  // printf("variable type set\n");
  HYPRE_SStructGridAssemble(grid);
  // printf("grid assembled\n");
  
  // Set up the stencil 
  HYPRE_SStructStencilCreate(2, 5, &stencil);
  int entry;
  int offsets[5][2] = { { 0, 0 }, { -1, 0 }, { 1, 0 }, { 0, -1 }, { 0, 1 } };
  int var = 0;

  for (entry = 0; entry < 5; entry++) {
    HYPRE_SStructStencilSetEntry(stencil, entry, offsets[entry], var);
  }

  // Create the graph 
  HYPRE_SStructGraphCreate(MPI_COMM_WORLD, grid, &graph);

  int object_type = HYPRE_PARCSR;

  HYPRE_SStructGraphSetObjectType(graph, object_type);

  HYPRE_SStructGraphSetStencil(graph, part, var, stencil);
  HYPRE_SStructGraphAssemble(graph);

  int nentries = 5;
  int nvalues = nentries * nx * ny;
  double *values;
  int stencil_indices[5];

  // Setup the matrix 
  HYPRE_SStructMatrixCreate(MPI_COMM_WORLD, graph, &A);
  HYPRE_SStructMatrixSetObjectType(A, HYPRE_PARCSR);
  HYPRE_SStructMatrixInitialize(A);

  // Set the matrix coefficients 
  values = calloc(nvalues, sizeof(double));
  for (j = 0; j < nentries; j++) {
    stencil_indices[j] = j;
  }

  // Account for differences in hx and hy 
  double hx2 = hx * hx;
  double hy2 = hy * hy;
  double hx2inv = 1 / hx2;
  double hy2inv = 1 / hy2;

  for (i = 0; i < nvalues; i += nentries) {
    values[i] = -2.0 * hx2inv - 2.0 * hy2inv;
    values[i + 1] = hx2inv;
    values[i + 2] = hx2inv;
    values[i + 3] = hy2inv;
    values[i + 4] = hy2inv;
  }

  HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper, var, nentries,
                                  stencil_indices, values);

  // Set the dirchelet boundary condition
  {
    int bc_ilower[2];
    int bc_iupper[2];
    int nentries = 1;
    int nvaluesx = nentries * nx; /*  number of stencil entries times the length
                                      of one side of my grid box */
    int nvaluesy = nentries * ny;
    double *valuesx, *valuesy, *center_valuesx, *center_valuesy;
    int stencil_indices[1];
    int center_index[1];
    center_index[0] = 0;

    valuesx = calloc(nvaluesx, sizeof(double));
    center_valuesx = calloc(nvaluesx, sizeof(double));
    for (j = 0; j < nvaluesx; j++){
      valuesx[j] = 0.0;
      center_valuesx[j] = -hx2inv;
    }

    valuesy = calloc(nvaluesy, sizeof(double));
    center_valuesy = calloc(nvaluesy, sizeof(double));
    for (j = 0; j < nvaluesy; j++){
      valuesy[j] = 0.0;
      center_valuesy[j] = -hy2inv;
     }
 

    // Recall: pi and pj describe position in the processor grid 
    if (pj == 0) {
      // Bottom row of grid points 
      bc_ilower[0] = pi * nx;
      bc_ilower[1] = pj * ny;

      bc_iupper[0] = bc_ilower[0] + nx - 1;
      bc_iupper[1] = bc_ilower[1];

      stencil_indices[0] = 3;

      HYPRE_SStructMatrixSetBoxValues(A, part, bc_ilower, bc_iupper, var,
                                      nentries, stencil_indices, valuesy);
      HYPRE_SStructMatrixAddToBoxValues(A, part, bc_ilower, bc_iupper, var, nentries, center_index, center_valuesy);
      // printf("Bottom row zeroed\n");
    }

    if (pj == Ny - 1) {
      // upper row of grid points 
      bc_ilower[0] = pi * nx;
      bc_ilower[1] = pj * ny + ny - 1;

      bc_iupper[0] = bc_ilower[0] + ny - 1;
      bc_iupper[1] = bc_ilower[1];

      stencil_indices[0] = 4;

      HYPRE_SStructMatrixSetBoxValues(A, part, bc_ilower, bc_iupper, var,
                                      nentries, stencil_indices, valuesy);
      HYPRE_SStructMatrixAddToBoxValues(A, part, bc_ilower, bc_iupper, var, nentries, center_index, center_valuesy);
      // printf("Upper row zeroed\n");
    }
    if (pi == 0) {
      // Left row of grid points 
      bc_ilower[0] = pi * nx;
      bc_ilower[1] = pj * ny;

      bc_iupper[0] = bc_ilower[0];
      bc_iupper[1] = bc_ilower[1] + ny - 1;

      stencil_indices[0] = 1;

      HYPRE_SStructMatrixSetBoxValues(A, part, bc_ilower, bc_iupper, var,
                                      nentries, stencil_indices, valuesx);
      HYPRE_SStructMatrixAddToBoxValues(A, part, bc_ilower, bc_iupper, var, nentries, center_index, center_valuesx); 
      // printf("left collumn zeroed\n");
    }

    if (pi == Nx - 1) {
      // Right row of grid points 
      bc_ilower[0] = pi * nx + nx - 1;
      bc_ilower[1] = pj * ny;

      bc_iupper[0] = bc_ilower[0];
      bc_iupper[1] = bc_ilower[1] + ny - 1;

      stencil_indices[0] = 2;

      HYPRE_SStructMatrixSetBoxValues(A, part, bc_ilower, bc_iupper, var,
                                      nentries, stencil_indices, valuesx);
      HYPRE_SStructMatrixAddToBoxValues(A, part, bc_ilower, bc_iupper, var, nentries, center_index, center_valuesx);
      // printf("right collumn zeroed\n");
    }
    free(valuesx);
    free(center_valuesx);
    free(valuesy);
    free(center_valuesy);
  }

  HYPRE_SStructMatrixAssemble(A);
  HYPRE_SStructMatrixGetObject(A, (void **)&parcsr_A);

  // Create the right hand side and solution vectors 
  HYPRE_SStructVectorCreate(MPI_COMM_WORLD, grid, &b);
  HYPRE_SStructVectorSetObjectType(b, HYPRE_PARCSR);
  HYPRE_SStructVectorInitialize(b);

  HYPRE_SStructVectorCreate(MPI_COMM_WORLD, grid, &x);
  HYPRE_SStructVectorSetObjectType(x, HYPRE_PARCSR);
  HYPRE_SStructVectorInitialize(x);

  // Set the right hand side, exact solution, and initial guess values 
  double *rhs_values, *x_values, *exactsolution;
  nvalues = nx * ny;

  rhs_values = calloc(nvalues, sizeof(double));
  x_values = calloc(nvalues, sizeof(double));
  exactsolution = calloc(nvalues, sizeof(double));
  // printf("RHS calculation begin\n");
    for (j = 0; j < ny; j++) {
    double y =  (ilower[1] + j + .5) * hy;
    for (i = 0; i < nx; i++) {
      double x = (ilower[0] + i + .5) * hx;
      rhs_values[i + j * nx] =
          -8. * PI2 * sin(2. * M_PI * x) * sin(2. * M_PI * y);
      exactsolution[i + j * nx] = 1.0 * sin(2. * M_PI * x) * sin(2. * M_PI * y);
      x_values[i + j * nx] = 0.0;
    }
  }
  // printf("RHS calculation ended\n");
  HYPRE_SStructVectorSetBoxValues(b, part, ilower, iupper, var, rhs_values);
  HYPRE_SStructVectorSetBoxValues(x, part, ilower, iupper, var, x_values);


  //printf("%d  %f\n", (ny*nx-1), exactsolution[ny*nx-1]);
  

  free(x_values);
  free(rhs_values);

  HYPRE_SStructVectorAssemble(b);
  // HYPRE_SStructVectorPrint("ss.initial.b", b, 0);
  HYPRE_SStructVectorGetObject(b, (void **)&par_b);
  HYPRE_SStructVectorAssemble(x);
  HYPRE_SStructVectorGetObject(x, (void **)&par_x);

  // Print out initial vectors 
  HYPRE_SStructMatrixPrint("SStructExact/ss.initial.A", A, 0);
  HYPRE_SStructVectorPrint("SStructExact/ss.initial.b", b, 0);
  // printf("About to solve\n");

  // Select a solver 
  if (solver_id == 0) {
    int num_iterations;
    double final_res_norm;

    // Create AMG solver 
    HYPRE_BoomerAMGCreate(&solver);

    // Set solver parameters 
    HYPRE_BoomerAMGSetPrintLevel(solver, 3);
    HYPRE_BoomerAMGSetCoarsenType(solver, 6);
    HYPRE_BoomerAMGSetRelaxType(solver, 3);
    HYPRE_BoomerAMGSetNumSweeps(solver, 1);
    HYPRE_BoomerAMGSetMaxLevels(solver, 20);
    HYPRE_BoomerAMGSetTol(solver, 1e-12);
    HYPRE_BoomerAMGSetMaxIter(solver, 100);
    // Set up and solve 
    HYPRE_BoomerAMGSetup(solver, parcsr_A, par_b, par_x);
    HYPRE_BoomerAMGSolve(solver, parcsr_A, par_b, par_x);
    //printf("solution obtained\n");
  
    // Run information 
    HYPRE_BoomerAMGGetNumIterations(solver, &num_iterations);
    HYPRE_BoomerAMGGetFinalRelativeResidualNorm(solver, &final_res_norm);
    if (myid == 0) {
      printf("\n");
      printf("Iterations = %d\n", num_iterations);
      printf("Final Relative Residual Norm = %e\n", final_res_norm);
      printf("\n");
    }

    // Destroy solver 
    HYPRE_BoomerAMGDestroy(solver);
    // HYPRE_ParVectorPrint(par_x, "SStructExact/ss.final.x");
    char solutionfile[255];
    sprintf(solutionfile, "%s.%06d", "ss.final.x", myid);
    HYPRE_ParVectorPrint(par_x, solutionfile);
  }

  // Save the solution for visualization and L2 norm calculation  
  if (vis) {
    FILE *file;
    FILE *solution;

    char filename[255];
    char solutionfile[255];

    sprintf(solutionfile, "%s.%06d.%d", "ss.final.x", myid, myid);

    int nvalues = nx * ny;

    double sum = 0;
    double diff, diff2, L2;

    // get the localally calculated and exact solutions)
    double *values = calloc(nvalues+1, sizeof(double));

    // Opens the local solution file, reads the solution to the array, values
    // and closes the file. 

    // Opens the solution file 
    if ((solution = fopen(solutionfile, "rt")) == NULL) {
      printf("Error: can't open output file %s\n", solutionfile);
      MPI_Finalize();
      exit(1);
    }

    // Reads the file to the array values 
    for (i = 0; i < nvalues + 1; i++) {
      fscanf(solution, "%lf", &values[i]);
    }

    // Close the file 
    fflush(solution);
    fclose(solution);

    MPI_Barrier(MPI_COMM_WORLD);

    // Calcluates the sum of the squared differences for the exact and numerical solutions on each processor   
  for (i = 1; i < nvalues + 1; i++) {
      diff = values[i] - exactsolution[i-1];
      diff2 = diff * diff;
      if (diff2 > 10){
       printf("%+6f       %+6f     %+6d\n", values[i], exactsolution[i-1],
       i-1);
      }
      sum += diff2;
      }
    //printf("Myid is: %d and mysum is: %f\n", myid, sum);
    
   //  Ensure all processors are caught up 
    MPI_Barrier(MPI_COMM_WORLD);
 
    // Passes the individual sums to processor 0 and sums them. 
    double *sendbuffer, *recvbuffer;
    sendbuffer = calloc(1,  sizeof(double));
    sendbuffer[0] = sum;
    recvbuffer = calloc(1, sizeof(double));
    int root = 0;
    int count = 1;
    MPI_Reduce(sendbuffer, recvbuffer, count, MPI_DOUBLE, MPI_SUM, root, MPI_COMM_WORLD);
    MPI_Barrier(MPI_COMM_WORLD);
 
  // Calculates the L2 norm  
  if (myid == 0){
      //printf("%f\n" , recvbuffer[myid]);
      // nvalues = (nx-2)*(ny-2);      
      double totalvalues = nvalues * num_procs * 1.0; 

      L2 = sqrt(recvbuffer[0] / totalvalues);      
      printf("The L2 norm is %e\n", L2);    
    }
   
    sprintf(filename, "%s.%06d", "vis/ss.sol", myid);

    if ((file = fopen(filename, "w")) == NULL) {
      printf("Error: can't open output file %s\n", filename);
      MPI_Finalize();
      exit(1);
    }

    // Save solution 
    for (i = 1; i < nvalues+1; i++) {
      fprintf(file, "%.14e\n", values[i]);
    }

    // Vis Cleanup
    fflush(file);
    fclose(file);

    free(values);
    free(exactsolution);
    free(sendbuffer);
    free(recvbuffer);

    // save global finite element mesh 
    if (myid == 0) {
      GLVis_PrintGlobalMesh("vis/ss.mesh", Nx, Ny, nx, ny, hx, hy);
    }
 } 

  // Clean up 

  HYPRE_SStructMatrixDestroy(A);
  HYPRE_SStructVectorDestroy(b);
  HYPRE_SStructVectorDestroy(x);

  // Finalize MPI*/
  
  MPI_Finalize();

  return (0);
}