Пример #1
0
Файл: ml.c Проект: Kun-Qu/petsc
PetscErrorCode PCSetUp_ML(PC pc)
{
  PetscErrorCode  ierr;
  PetscMPIInt     size;
  FineGridCtx     *PetscMLdata;
  ML              *ml_object;
  ML_Aggregate    *agg_object;
  ML_Operator     *mlmat;
  PetscInt        nlocal_allcols,Nlevels,mllevel,level,level1,m,fine_level,bs;
  Mat             A,Aloc; 
  GridCtx         *gridctx; 
  PC_MG           *mg = (PC_MG*)pc->data;
  PC_ML           *pc_ml = (PC_ML*)mg->innerctx;
  PetscBool       isSeq, isMPI;
  KSP             smoother;
  PC              subpc;
  PetscInt        mesh_level, old_mesh_level;

  PetscFunctionBegin;
  A = pc->pmat;
  ierr = MPI_Comm_size(((PetscObject)A)->comm,&size);CHKERRQ(ierr);

  if (pc->setupcalled) {
    if (pc->flag == SAME_NONZERO_PATTERN && pc_ml->reuse_interpolation) {
      /*
       Reuse interpolaton instead of recomputing aggregates and updating the whole hierarchy. This is less expensive for
       multiple solves in which the matrix is not changing too quickly.
       */
      ml_object = pc_ml->ml_object;
      gridctx = pc_ml->gridctx;
      Nlevels = pc_ml->Nlevels;
      fine_level = Nlevels - 1;
      gridctx[fine_level].A = A;

      ierr = PetscObjectTypeCompare((PetscObject) A, MATSEQAIJ, &isSeq);CHKERRQ(ierr);
      ierr = PetscObjectTypeCompare((PetscObject) A, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
      if (isMPI){
        ierr = MatConvert_MPIAIJ_ML(A,PETSC_NULL,MAT_INITIAL_MATRIX,&Aloc);CHKERRQ(ierr);
      } else if (isSeq) {
        Aloc = A;
        ierr = PetscObjectReference((PetscObject)Aloc);CHKERRQ(ierr);
      } else SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONG, "Matrix type '%s' cannot be used with ML. ML can only handle AIJ matrices.",((PetscObject)A)->type_name);

      ierr = MatGetSize(Aloc,&m,&nlocal_allcols);CHKERRQ(ierr);
      PetscMLdata = pc_ml->PetscMLdata;
      ierr = MatDestroy(&PetscMLdata->Aloc);CHKERRQ(ierr);
      PetscMLdata->A    = A;
      PetscMLdata->Aloc = Aloc;
      ML_Init_Amatrix(ml_object,0,m,m,PetscMLdata);
      ML_Set_Amatrix_Matvec(ml_object,0,PetscML_matvec);

      mesh_level = ml_object->ML_finest_level;
      while (ml_object->SingleLevel[mesh_level].Rmat->to) {
        old_mesh_level = mesh_level;
        mesh_level = ml_object->SingleLevel[mesh_level].Rmat->to->levelnum;

        /* clean and regenerate A */
        mlmat = &(ml_object->Amat[mesh_level]);
        ML_Operator_Clean(mlmat);
        ML_Operator_Init(mlmat,ml_object->comm);
        ML_Gen_AmatrixRAP(ml_object, old_mesh_level, mesh_level);
      }

      level = fine_level - 1;
      if (size == 1) { /* convert ML P, R and A into seqaij format */
        for (mllevel=1; mllevel<Nlevels; mllevel++){
          mlmat = &(ml_object->Amat[mllevel]);
          ierr = MatWrapML_SeqAIJ(mlmat,MAT_REUSE_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
          level--;
        }
      } else { /* convert ML P and R into shell format, ML A into mpiaij format */
        for (mllevel=1; mllevel<Nlevels; mllevel++){
          mlmat  = &(ml_object->Amat[mllevel]);
          ierr = MatWrapML_MPIAIJ(mlmat,MAT_REUSE_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
          level--;
        }
      }

      for (level=0; level<fine_level; level++) {
        if (level > 0){
          ierr = PCMGSetResidual(pc,level,PCMGDefaultResidual,gridctx[level].A);CHKERRQ(ierr);
        }
        ierr = KSPSetOperators(gridctx[level].ksp,gridctx[level].A,gridctx[level].A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
      }
      ierr = PCMGSetResidual(pc,fine_level,PCMGDefaultResidual,gridctx[fine_level].A);CHKERRQ(ierr);
      ierr = KSPSetOperators(gridctx[fine_level].ksp,gridctx[level].A,gridctx[fine_level].A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);

      ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
      PetscFunctionReturn(0);
    } else {
      /* since ML can change the size of vectors/matrices at any level we must destroy everything */
      ierr = PCReset_ML(pc);CHKERRQ(ierr);
      ierr = PCReset_MG(pc);CHKERRQ(ierr);
    }
  }

  /* setup special features of PCML */
  /*--------------------------------*/
  /* covert A to Aloc to be used by ML at fine grid */
  pc_ml->size = size;
  ierr = PetscObjectTypeCompare((PetscObject) A, MATSEQAIJ, &isSeq);CHKERRQ(ierr);
  ierr = PetscObjectTypeCompare((PetscObject) A, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
  if (isMPI){ 
    ierr = MatConvert_MPIAIJ_ML(A,PETSC_NULL,MAT_INITIAL_MATRIX,&Aloc);CHKERRQ(ierr);
  } else if (isSeq) {
    Aloc = A;
    ierr = PetscObjectReference((PetscObject)Aloc);CHKERRQ(ierr);
  } else SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_WRONG, "Matrix type '%s' cannot be used with ML. ML can only handle AIJ matrices.",((PetscObject)A)->type_name);

  /* create and initialize struct 'PetscMLdata' */
  ierr = PetscNewLog(pc,FineGridCtx,&PetscMLdata);CHKERRQ(ierr); 
  pc_ml->PetscMLdata = PetscMLdata;
  ierr = PetscMalloc((Aloc->cmap->n+1)*sizeof(PetscScalar),&PetscMLdata->pwork);CHKERRQ(ierr); 

  ierr = VecCreate(PETSC_COMM_SELF,&PetscMLdata->x);CHKERRQ(ierr);   
  ierr = VecSetSizes(PetscMLdata->x,Aloc->cmap->n,Aloc->cmap->n);CHKERRQ(ierr);
  ierr = VecSetType(PetscMLdata->x,VECSEQ);CHKERRQ(ierr); 

  ierr = VecCreate(PETSC_COMM_SELF,&PetscMLdata->y);CHKERRQ(ierr); 
  ierr = VecSetSizes(PetscMLdata->y,A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
  ierr = VecSetType(PetscMLdata->y,VECSEQ);CHKERRQ(ierr);
  PetscMLdata->A    = A;
  PetscMLdata->Aloc = Aloc;
   
  /* create ML discretization matrix at fine grid */
  /* ML requires input of fine-grid matrix. It determines nlevels. */
  ierr = MatGetSize(Aloc,&m,&nlocal_allcols);CHKERRQ(ierr);
  ierr = MatGetBlockSize(A,&bs);CHKERRQ(ierr);
  ML_Create(&ml_object,pc_ml->MaxNlevels);
  ML_Comm_Set_UsrComm(ml_object->comm,((PetscObject)A)->comm);
  pc_ml->ml_object = ml_object;
  ML_Init_Amatrix(ml_object,0,m,m,PetscMLdata);
  ML_Set_Amatrix_Getrow(ml_object,0,PetscML_getrow,PetscML_comm,nlocal_allcols); 
  ML_Set_Amatrix_Matvec(ml_object,0,PetscML_matvec);

  ML_Set_Symmetrize(ml_object,pc_ml->Symmetrize ? ML_YES : ML_NO);

  /* aggregation */
  ML_Aggregate_Create(&agg_object); 
  pc_ml->agg_object = agg_object;

  {
    MatNullSpace mnull;
    ierr = MatGetNearNullSpace(A,&mnull);CHKERRQ(ierr);
    if (pc_ml->nulltype == PCML_NULLSPACE_AUTO) {
      if (mnull) pc_ml->nulltype = PCML_NULLSPACE_USER;
      else if (bs > 1) pc_ml->nulltype = PCML_NULLSPACE_BLOCK;
      else pc_ml->nulltype = PCML_NULLSPACE_SCALAR;
    }
    switch (pc_ml->nulltype) {
    case PCML_NULLSPACE_USER: {
      PetscScalar *nullvec;
      const PetscScalar *v;
      PetscBool has_const;
      PetscInt i,j,mlocal,nvec,M;
      const Vec *vecs;
      if (!mnull) SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_USER,"Must provide explicit null space using MatSetNearNullSpace() to use user-specified null space");
      ierr = MatGetSize(A,&M,PETSC_NULL);CHKERRQ(ierr);
      ierr = MatGetLocalSize(Aloc,&mlocal,PETSC_NULL);CHKERRQ(ierr);
      ierr = MatNullSpaceGetVecs(mnull,&has_const,&nvec,&vecs);CHKERRQ(ierr);
      ierr = PetscMalloc((nvec+!!has_const)*mlocal*sizeof *nullvec,&nullvec);CHKERRQ(ierr);
      if (has_const) for (i=0; i<mlocal; i++) nullvec[i] = 1.0/M;
      for (i=0; i<nvec; i++) {
        ierr = VecGetArrayRead(vecs[i],&v);CHKERRQ(ierr);
        for (j=0; j<mlocal; j++) nullvec[(i+!!has_const)*mlocal + j] = v[j];
        ierr = VecRestoreArrayRead(vecs[i],&v);CHKERRQ(ierr);
      }
      ierr = ML_Aggregate_Set_NullSpace(agg_object,bs,nvec+!!has_const,nullvec,mlocal);CHKERRQ(ierr);
      ierr = PetscFree(nullvec);CHKERRQ(ierr);
    } break;
    case PCML_NULLSPACE_BLOCK:
      ierr = ML_Aggregate_Set_NullSpace(agg_object,bs,bs,0,0);CHKERRQ(ierr);
      break;
    case PCML_NULLSPACE_SCALAR:
      break;
    default: SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_SUP,"Unknown null space type");
    }
  }
  ML_Aggregate_Set_MaxCoarseSize(agg_object,pc_ml->MaxCoarseSize);
  /* set options */
  switch (pc_ml->CoarsenScheme) { 
  case 1:  
    ML_Aggregate_Set_CoarsenScheme_Coupled(agg_object);break;
  case 2:
    ML_Aggregate_Set_CoarsenScheme_MIS(agg_object);break;
  case 3:
    ML_Aggregate_Set_CoarsenScheme_METIS(agg_object);break;
  }
  ML_Aggregate_Set_Threshold(agg_object,pc_ml->Threshold); 
  ML_Aggregate_Set_DampingFactor(agg_object,pc_ml->DampingFactor); 
  if (pc_ml->SpectralNormScheme_Anorm){
    ML_Set_SpectralNormScheme_Anorm(ml_object);
  }
  agg_object->keep_agg_information      = (int)pc_ml->KeepAggInfo;
  agg_object->keep_P_tentative          = (int)pc_ml->Reusable;
  agg_object->block_scaled_SA           = (int)pc_ml->BlockScaling;
  agg_object->minimizing_energy         = (int)pc_ml->EnergyMinimization;
  agg_object->minimizing_energy_droptol = (double)pc_ml->EnergyMinimizationDropTol;
  agg_object->cheap_minimizing_energy   = (int)pc_ml->EnergyMinimizationCheap;

  if (pc_ml->OldHierarchy) {
    Nlevels = ML_Gen_MGHierarchy_UsingAggregation(ml_object,0,ML_INCREASING,agg_object);
  } else {
    Nlevels = ML_Gen_MultiLevelHierarchy_UsingAggregation(ml_object,0,ML_INCREASING,agg_object);
  }
  if (Nlevels<=0) SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_ARG_OUTOFRANGE,"Nlevels %d must > 0",Nlevels);
  pc_ml->Nlevels = Nlevels;
  fine_level = Nlevels - 1;

  ierr = PCMGSetLevels(pc,Nlevels,PETSC_NULL);CHKERRQ(ierr); 
  /* set default smoothers */
  for (level=1; level<=fine_level; level++){
    if (size == 1){
      ierr = PCMGGetSmoother(pc,level,&smoother);CHKERRQ(ierr);
      ierr = KSPSetType(smoother,KSPRICHARDSON);CHKERRQ(ierr);
      ierr = KSPGetPC(smoother,&subpc);CHKERRQ(ierr);
      ierr = PCSetType(subpc,PCSOR);CHKERRQ(ierr);
    } else {
      ierr = PCMGGetSmoother(pc,level,&smoother);CHKERRQ(ierr);
      ierr = KSPSetType(smoother,KSPRICHARDSON);CHKERRQ(ierr);
      ierr = KSPGetPC(smoother,&subpc);CHKERRQ(ierr);
      ierr = PCSetType(subpc,PCSOR);CHKERRQ(ierr);
    }
  }
  ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
  ierr = PCSetFromOptions_MG(pc);CHKERRQ(ierr); /* should be called in PCSetFromOptions_ML(), but cannot be called prior to PCMGSetLevels() */
  ierr = PetscOptionsEnd();CHKERRQ(ierr);

  ierr = PetscMalloc(Nlevels*sizeof(GridCtx),&gridctx);CHKERRQ(ierr);
  pc_ml->gridctx = gridctx;

  /* wrap ML matrices by PETSc shell matrices at coarsened grids.
     Level 0 is the finest grid for ML, but coarsest for PETSc! */
  gridctx[fine_level].A = A;

  level = fine_level - 1;
  if (size == 1){ /* convert ML P, R and A into seqaij format */
    for (mllevel=1; mllevel<Nlevels; mllevel++){ 
      mlmat = &(ml_object->Pmat[mllevel]);
      ierr  = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].P);CHKERRQ(ierr);
      mlmat = &(ml_object->Rmat[mllevel-1]);
      ierr  = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].R);CHKERRQ(ierr);
      
      mlmat = &(ml_object->Amat[mllevel]);
      ierr  = MatWrapML_SeqAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].A);CHKERRQ(ierr);
      level--;
    }
  } else { /* convert ML P and R into shell format, ML A into mpiaij format */
    for (mllevel=1; mllevel<Nlevels; mllevel++){ 
      mlmat  = &(ml_object->Pmat[mllevel]);
      ierr = MatWrapML_SHELL(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].P);CHKERRQ(ierr);
      mlmat  = &(ml_object->Rmat[mllevel-1]);
      ierr = MatWrapML_SHELL(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].R);CHKERRQ(ierr);

      mlmat  = &(ml_object->Amat[mllevel]);
      ierr = MatWrapML_MPIAIJ(mlmat,MAT_INITIAL_MATRIX,&gridctx[level].A);CHKERRQ(ierr);  
      level--;
    }
  }

  /* create vectors and ksp at all levels */
  for (level=0; level<fine_level; level++){  
    level1 = level + 1;
    ierr = VecCreate(((PetscObject)gridctx[level].A)->comm,&gridctx[level].x);CHKERRQ(ierr); 
    ierr = VecSetSizes(gridctx[level].x,gridctx[level].A->cmap->n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetType(gridctx[level].x,VECMPI);CHKERRQ(ierr); 
    ierr = PCMGSetX(pc,level,gridctx[level].x);CHKERRQ(ierr); 
   
    ierr = VecCreate(((PetscObject)gridctx[level].A)->comm,&gridctx[level].b);CHKERRQ(ierr); 
    ierr = VecSetSizes(gridctx[level].b,gridctx[level].A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetType(gridctx[level].b,VECMPI);CHKERRQ(ierr); 
    ierr = PCMGSetRhs(pc,level,gridctx[level].b);CHKERRQ(ierr); 
    
    ierr = VecCreate(((PetscObject)gridctx[level1].A)->comm,&gridctx[level1].r);CHKERRQ(ierr); 
    ierr = VecSetSizes(gridctx[level1].r,gridctx[level1].A->rmap->n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetType(gridctx[level1].r,VECMPI);CHKERRQ(ierr); 
    ierr = PCMGSetR(pc,level1,gridctx[level1].r);CHKERRQ(ierr);

    if (level == 0){
      ierr = PCMGGetCoarseSolve(pc,&gridctx[level].ksp);CHKERRQ(ierr);
    } else {
      ierr = PCMGGetSmoother(pc,level,&gridctx[level].ksp);CHKERRQ(ierr);
    }  
  }
  ierr = PCMGGetSmoother(pc,fine_level,&gridctx[fine_level].ksp);CHKERRQ(ierr);

  /* create coarse level and the interpolation between the levels */
  for (level=0; level<fine_level; level++){  
    level1 = level + 1;
    ierr = PCMGSetInterpolation(pc,level1,gridctx[level].P);CHKERRQ(ierr);
    ierr = PCMGSetRestriction(pc,level1,gridctx[level].R);CHKERRQ(ierr);     
    if (level > 0){
      ierr = PCMGSetResidual(pc,level,PCMGDefaultResidual,gridctx[level].A);CHKERRQ(ierr);
    }    
    ierr = KSPSetOperators(gridctx[level].ksp,gridctx[level].A,gridctx[level].A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);      
  }  
  ierr = PCMGSetResidual(pc,fine_level,PCMGDefaultResidual,gridctx[fine_level].A);CHKERRQ(ierr); 
  ierr = KSPSetOperators(gridctx[fine_level].ksp,gridctx[level].A,gridctx[fine_level].A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);

  /* setupcalled is set to 0 so that MG is setup from scratch */
  pc->setupcalled = 0;  
  ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
Пример #2
0
int main(int argc, char *argv[])
{
  int num_PDE_eqns=1, N_levels=3, nsmooth=2;

  int leng, level, N_grid_pts, coarsest_level;
  int leng1,leng2;
  /* See Aztec User's Guide for more information on the */
  /* variables that follow.                             */

  int    proc_config[AZ_PROC_SIZE], options[AZ_OPTIONS_SIZE];
  double params[AZ_PARAMS_SIZE], status[AZ_STATUS_SIZE];

  /* data structure for matrix corresponding to the fine grid */

  double *val = NULL, *xxx, *rhs, solve_time, setup_time, start_time;
  AZ_MATRIX *Amat;
  AZ_PRECOND *Pmat = NULL;
  ML *ml;
  FILE *fp;
  int i, j, Nrigid, *garbage, nblocks=0, *blocks = NULL, *block_pde=NULL;
  struct AZ_SCALING *scaling;
  ML_Aggregate *ag;
  double *mode, *rigid=NULL, alpha; 
  char filename[80];
  int    one = 1;
  int    proc,nprocs;
  char pathfilename[100];

#ifdef ML_MPI
  MPI_Init(&argc,&argv);
  /* get number of processors and the name of this processor */
  AZ_set_proc_config(proc_config, MPI_COMM_WORLD);
  proc   = proc_config[AZ_node];
  nprocs = proc_config[AZ_N_procs];
#else
  AZ_set_proc_config(proc_config, AZ_NOT_MPI);
  proc   = 0;
  nprocs = 1;
#endif

   if (proc_config[AZ_node] == 0) {
      sprintf(pathfilename,"%s/inputfile",argv[1]);
      ML_Reader_ReadInput(pathfilename, &context);
   }
   else context = (struct reader_context *) ML_allocate(sizeof(struct reader_context));
   AZ_broadcast((char *) context,  sizeof(struct reader_context), proc_config,
                AZ_PACK);
   AZ_broadcast((char *) NULL        ,   0          , proc_config, AZ_SEND);

   N_levels = context->N_levels;
   printf("N_levels %d\n",N_levels);
   nsmooth   = context->nsmooth;
   num_PDE_eqns = context->N_dofPerNode;
   printf("num_PDE_eqns %d\n",num_PDE_eqns);

   ML_Set_PrintLevel(context->output_level);

  /* read in the number of matrix equations */
  leng = 0;
  if (proc_config[AZ_node] == 0) {
        sprintf(pathfilename,"%s/data_matrix.txt",argv[1]);
        fp=fopen(pathfilename,"r");
     if (fp==NULL) {
        printf("**ERR** couldn't open file data_matrix.txt\n");
        exit(1);
     }
        fscanf(fp,"%d",&leng);
     fclose(fp);
  }
  leng = AZ_gsum_int(leng, proc_config);

  N_grid_pts=leng/num_PDE_eqns;


  /* initialize the list of global indices. NOTE: the list of global */
  /* indices must be in ascending order so that subsequent calls to  */
  /* AZ_find_index() will function properly. */
#if 0
  if (proc_config[AZ_N_procs] == 1) i = AZ_linear;
  else i = AZ_file;
#endif
  i = AZ_linear;

  /* cannot use AZ_input_update for variable blocks (forgot why, but debugged through it)*/
  /* make a linear distribution of the matrix       */
  /* if the linear distribution does not align with the blocks, */
  /* this is corrected in ML_AZ_Reader_ReadVariableBlocks */
  leng1 = leng/nprocs;
  leng2 = leng-leng1*nprocs;
  if (proc >= leng2)
  {
     leng2 += (proc*leng1);
  }
  else
  {
     leng1++;
     leng2 = proc*leng1;
  }
  N_update = leng1;
  update = (int*)AZ_allocate((N_update+1)*sizeof(int));
  if (update==NULL)
  {
      (void) fprintf (stderr, "Not enough space to allocate 'update'\n");
      fflush(stderr); exit(EXIT_FAILURE);
  }
  for (i=0; i<N_update; i++) update[i] = i+leng2;
  
#if 0 /* debug */
  printf("proc %d N_update %d\n",proc_config[AZ_node],N_update);
  fflush(stdout);                   
#endif
  sprintf(pathfilename,"%s/data_vblocks.txt",argv[1]);
  ML_AZ_Reader_ReadVariableBlocks(pathfilename,&nblocks,&blocks,&block_pde,
                                  &N_update,&update,proc_config);
#if 0 /* debug */
  printf("proc %d N_update %d\n",proc_config[AZ_node],N_update);
  fflush(stdout);                   
#endif

  sprintf(pathfilename,"%s/data_matrix.txt",argv[1]);
  AZ_input_msr_matrix(pathfilename,update, &val, &bindx, N_update, proc_config);

  /* This code is to fix things up so that we are sure we have   */ 
  /* all blocks (including the ghost nodes) the same size.       */
  /* not sure, whether this is a good idea with variable blocks  */
  /* the examples inpufiles (see top of this file) don't need it */
  /* anyway                                                      */
  /*
  AZ_block_MSR(&bindx, &val, N_update, num_PDE_eqns, update);
  */
  AZ_transform_norowreordering(proc_config, &external, bindx, val,  update, &update_index,
	       &extern_index, &data_org, N_update, 0, 0, 0, &cpntr,
	       AZ_MSR_MATRIX);
	
  Amat = AZ_matrix_create( leng );

  AZ_set_MSR(Amat, bindx, val, data_org, 0, NULL, AZ_LOCAL);

  Amat->matrix_type  = data_org[AZ_matrix_type];
	
  data_org[AZ_N_rows]  = data_org[AZ_N_internal] + data_org[AZ_N_border];
			
  start_time = AZ_second();

  options[AZ_scaling] = AZ_none;

  ML_Create(&ml, N_levels);
			
			
  /* set up discretization matrix and matrix vector function */
  AZ_ML_Set_Amat(ml, 0, N_update, N_update, Amat, proc_config);

  ML_Set_ResidualOutputFrequency(ml, context->output);
  ML_Set_Tolerance(ml, context->tol);
  ML_Aggregate_Create( &ag );
  if (ML_strcmp(context->agg_coarsen_scheme,"Mis") == 0) {
     ML_Aggregate_Set_CoarsenScheme_MIS(ag);
  }
  else if (ML_strcmp(context->agg_coarsen_scheme,"Uncoupled") == 0) {
     ML_Aggregate_Set_CoarsenScheme_Uncoupled(ag);
  }
  else if (ML_strcmp(context->agg_coarsen_scheme,"Coupled") == 0) {
     ML_Aggregate_Set_CoarsenScheme_Coupled(ag);
  }
  else if (ML_strcmp(context->agg_coarsen_scheme,"Metis") == 0) {
     ML_Aggregate_Set_CoarsenScheme_METIS(ag);
     for (i=0; i<N_levels; i++)
        ML_Aggregate_Set_NodesPerAggr(ml,ag,i,9);
  }
  else if (ML_strcmp(context->agg_coarsen_scheme,"VBMetis") == 0) {
     /* when no blocks read, use standard metis assuming constant block sizes */
     if (!blocks) 
        ML_Aggregate_Set_CoarsenScheme_METIS(ag);
     else {
        ML_Aggregate_Set_CoarsenScheme_VBMETIS(ag);
        ML_Aggregate_Set_Vblocks_CoarsenScheme_VBMETIS(ag,0,N_levels,nblocks,
                                                       blocks,block_pde,N_update);
     }
     for (i=0; i<N_levels; i++)
        ML_Aggregate_Set_NodesPerAggr(ml,ag,i,9);
  }
  else {
     printf("**ERR** ML: Unknown aggregation scheme %s\n",context->agg_coarsen_scheme);
     exit(-1);
  }
  ML_Aggregate_Set_DampingFactor(ag, context->agg_damping);
  ML_Aggregate_Set_MaxCoarseSize( ag, context->maxcoarsesize);
  ML_Aggregate_Set_Threshold(ag, context->agg_thresh);

  if (ML_strcmp(context->agg_spectral_norm,"Calc") == 0) {
     ML_Set_SpectralNormScheme_Calc(ml);
  }
  else if (ML_strcmp(context->agg_spectral_norm,"Anorm") == 0) {
     ML_Set_SpectralNormScheme_Anorm(ml);
  }
  else {
     printf("**WRN** ML: Unknown spectral norm scheme %s\n",context->agg_spectral_norm);
  }

  /* read in the rigid body modes */

   Nrigid = 0;
   if (proc_config[AZ_node] == 0) {
      sprintf(filename,"data_nullsp%d.txt",Nrigid);
      sprintf(pathfilename,"%s/%s",argv[1],filename);
      while( (fp = fopen(pathfilename,"r")) != NULL) {
          fclose(fp);
          Nrigid++;
          sprintf(filename,"data_nullsp%d.txt",Nrigid);
          sprintf(pathfilename,"%s/%s",argv[1],filename);
      }
    }
    Nrigid = AZ_gsum_int(Nrigid,proc_config);

    if (Nrigid != 0) {
       rigid = (double *) ML_allocate( sizeof(double)*Nrigid*(N_update+1) );
       if (rigid == NULL) {
          printf("Error: Not enough space for rigid body modes\n");
       }
    }

   /* Set rhs */
   sprintf(pathfilename,"%s/data_rhs.txt",argv[1]);
   fp = fopen(pathfilename,"r");
   if (fp == NULL) {
      rhs=(double *)ML_allocate(leng*sizeof(double));
      if (proc_config[AZ_node] == 0) printf("taking linear vector for rhs\n");
      for (i = 0; i < N_update; i++) rhs[i] = (double) update[i];
   }
   else {
      fclose(fp);
      if (proc_config[AZ_node] == 0) printf("reading rhs from a file\n");
      AZ_input_msr_matrix(pathfilename, update, &rhs, &garbage, N_update, 
                          proc_config);
   }
   AZ_reorder_vec(rhs, data_org, update_index, NULL);

   for (i = 0; i < Nrigid; i++) {
      sprintf(filename,"data_nullsp%d.txt",i);
      sprintf(pathfilename,"%s/%s",argv[1],filename);
      AZ_input_msr_matrix(pathfilename, update, &mode, &garbage, N_update, 
                          proc_config);
      AZ_reorder_vec(mode, data_org, update_index, NULL);

#if 0 /* test the given rigid body mode, output-vector should be ~0 */
       Amat->matvec(mode, rigid, Amat, proc_config);
       for (j = 0; j < N_update; j++) printf("this is %d %e\n",j,rigid[j]);
#endif

    for (j = 0; j < i; j++) {
       alpha = -AZ_gdot(N_update, mode, &(rigid[j*N_update]), proc_config)/
                  AZ_gdot(N_update, &(rigid[j*N_update]), &(rigid[j*N_update]), 
                               proc_config);
       DAXPY_F77(&N_update, &alpha,  &(rigid[j*N_update]),  &one, mode, &one);
    }
   
    /* rhs orthogonalization */

    alpha = -AZ_gdot(N_update, mode, rhs, proc_config)/
                    AZ_gdot(N_update, mode, mode, proc_config);
    DAXPY_F77(&N_update, &alpha,  mode,  &one, rhs, &one);

    for (j = 0; j < N_update; j++) rigid[i*N_update+j] = mode[j];
    free(mode);
    free(garbage);
  }

  for (j = 0; j < Nrigid; j++) {
     alpha = -AZ_gdot(N_update, rhs, &(rigid[j*N_update]), proc_config)/
              AZ_gdot(N_update, &(rigid[j*N_update]), &(rigid[j*N_update]), 
                      proc_config);
     DAXPY_F77(&N_update, &alpha,  &(rigid[j*N_update]),  &one, rhs, &one);
  }

#if 0 /* for testing the default nullsp */
  ML_Aggregate_Set_NullSpace(ag, num_PDE_eqns, 6, NULL, N_update);
#else
  if (Nrigid != 0) {
     ML_Aggregate_Set_NullSpace(ag, num_PDE_eqns, Nrigid, rigid, N_update);
  }
#endif
  if (rigid) ML_free(rigid);

  ag->keep_agg_information = 1;
  coarsest_level = ML_Gen_MGHierarchy_UsingAggregation(ml, 0, 
                                            ML_INCREASING, ag);
  coarsest_level--;                                            

  if ( proc_config[AZ_node] == 0 )
	printf("Coarse level = %d \n", coarsest_level);
	
#if 0
  /* set up smoothers */
  if (!blocks)
     blocks = (int *) ML_allocate(sizeof(int)*N_update);
#endif

  for (level = 0; level < coarsest_level; level++) {

      num_PDE_eqns = ml->Amat[level].num_PDEs;
		
     /*  Sparse approximate inverse smoother that acutally does both */
     /*  pre and post smoothing.                                     */

     if (ML_strcmp(context->smoother,"Parasails") == 0) {
        ML_Gen_Smoother_ParaSails(ml , level, ML_PRESMOOTHER, nsmooth, 
                                parasails_sym, parasails_thresh, 
                                parasails_nlevels, parasails_filter,
                                (int) parasails_loadbal, parasails_factorized);
     }

     /* This is the symmetric Gauss-Seidel smoothing that we usually use. */
     /* In parallel, it is not a true Gauss-Seidel in that each processor */
     /* does a Gauss-Seidel on its local submatrix independent of the     */
     /* other processors.                                                 */

     else if (ML_strcmp(context->smoother,"GaussSeidel") == 0) {
       ML_Gen_Smoother_GaussSeidel(ml , level, ML_BOTH, nsmooth,1.);
     }
     else if (ML_strcmp(context->smoother,"SymGaussSeidel") == 0) {
       ML_Gen_Smoother_SymGaussSeidel(ml , level, ML_BOTH, nsmooth,1.);
     }
     else if (ML_strcmp(context->smoother,"Poly") == 0) {
       ML_Gen_Smoother_Cheby(ml, level, ML_BOTH, 30., nsmooth);
     }
     else if (ML_strcmp(context->smoother,"BlockGaussSeidel") == 0) {
       ML_Gen_Smoother_BlockGaussSeidel(ml , level, ML_BOTH, nsmooth,1.,
					 num_PDE_eqns);
     }
     else if (ML_strcmp(context->smoother,"VBSymGaussSeidel") == 0) {
         if (blocks)    ML_free(blocks);
         if (block_pde) ML_free(block_pde);
         blocks    = NULL;
         block_pde = NULL;
         nblocks   = 0;
         ML_Aggregate_Get_Vblocks_CoarsenScheme_VBMETIS(ag,level,N_levels,&nblocks,
                                                        &blocks,&block_pde);
         if (blocks==NULL) ML_Gen_Blocks_Aggregates(ag, level, &nblocks, &blocks);
         ML_Gen_Smoother_VBlockSymGaussSeidel(ml , level, ML_BOTH, nsmooth,1.,
                                              nblocks, blocks);
     }

     /* This is a true Gauss Seidel in parallel. This seems to work for  */
     /* elasticity problems.  However, I don't believe that this is very */
     /* efficient in parallel.                                           */       
     /*
      nblocks = ml->Amat[level].invec_leng;
      for (i =0; i < nblocks; i++) blocks[i] = i;
      ML_Gen_Smoother_VBlockSymGaussSeidelSequential(ml , level, ML_PRESMOOTHER,
                                                  nsmooth, 1., nblocks, blocks);
      ML_Gen_Smoother_VBlockSymGaussSeidelSequential(ml, level, ML_POSTSMOOTHER,
                                                  nsmooth, 1., nblocks, blocks);
     */

     /* Jacobi Smoothing                                                 */

     else if (ML_strcmp(context->smoother,"Jacobi") == 0) {
        ML_Gen_Smoother_Jacobi(ml , level, ML_PRESMOOTHER, nsmooth,.4);
        ML_Gen_Smoother_Jacobi(ml , level, ML_POSTSMOOTHER, nsmooth,.4);
     }

     /*  This does a block Gauss-Seidel (not true GS in parallel)        */
     /*  where each processor has 'nblocks' blocks.                      */
     /* */

     else if (ML_strcmp(context->smoother,"Metis") == 0) {
         if (blocks)    ML_free(blocks);
         if (block_pde) ML_free(block_pde);
         nblocks = 250;
         ML_Gen_Blocks_Metis(ml, level, &nblocks, &blocks);
         ML_Gen_Smoother_VBlockSymGaussSeidel(ml , level, ML_BOTH, nsmooth,1.,
                                        nblocks, blocks);
     }
     else {
         printf("unknown smoother %s\n",context->smoother);
         exit(1);
     }
   }
	
   /* set coarse level solver */
   nsmooth   = context->coarse_its;
   /*  Sparse approximate inverse smoother that acutally does both */
   /*  pre and post smoothing.                                     */

   if (ML_strcmp(context->coarse_solve,"Parasails") == 0) {
        ML_Gen_Smoother_ParaSails(ml , coarsest_level, ML_PRESMOOTHER, nsmooth, 
                                parasails_sym, parasails_thresh, 
                                parasails_nlevels, parasails_filter,
                                (int) parasails_loadbal, parasails_factorized);
   }

   else if (ML_strcmp(context->coarse_solve,"GaussSeidel") == 0) {
       ML_Gen_Smoother_GaussSeidel(ml , coarsest_level, ML_BOTH, nsmooth,1.);
   }
   else if (ML_strcmp(context->coarse_solve,"Poly") == 0) {
     ML_Gen_Smoother_Cheby(ml, coarsest_level, ML_BOTH, 30., nsmooth);
   }
   else if (ML_strcmp(context->coarse_solve,"SymGaussSeidel") == 0) {
       ML_Gen_Smoother_SymGaussSeidel(ml , coarsest_level, ML_BOTH, nsmooth,1.);
   }
   else if (ML_strcmp(context->coarse_solve,"BlockGaussSeidel") == 0) {
       ML_Gen_Smoother_BlockGaussSeidel(ml, coarsest_level, ML_BOTH, nsmooth,1.,
					num_PDE_eqns);
   }
   else if (ML_strcmp(context->coarse_solve,"Aggregate") == 0) {
         if (blocks)    ML_free(blocks);
         if (block_pde) ML_free(block_pde);
         ML_Gen_Blocks_Aggregates(ag, coarsest_level, &nblocks, &blocks);
         ML_Gen_Smoother_VBlockSymGaussSeidel(ml , coarsest_level, ML_BOTH, 
                                        nsmooth,1., nblocks, blocks);
   }
   else if (ML_strcmp(context->coarse_solve,"Jacobi") == 0) {
        ML_Gen_Smoother_Jacobi(ml , coarsest_level, ML_BOTH, nsmooth,.5);
   }
   else if (ML_strcmp(context->coarse_solve,"Metis") == 0) {
         if (blocks)    ML_free(blocks);
         if (block_pde) ML_free(block_pde);
         nblocks = 250;
         ML_Gen_Blocks_Metis(ml, coarsest_level, &nblocks, &blocks);
         ML_Gen_Smoother_VBlockSymGaussSeidel(ml , coarsest_level, ML_BOTH, 
                                              nsmooth,1., nblocks, blocks);
   }
   else if (ML_strcmp(context->coarse_solve,"SuperLU") == 0) {
      ML_Gen_CoarseSolverSuperLU( ml, coarsest_level);
   }
   else if (ML_strcmp(context->coarse_solve,"Amesos") == 0) {
      ML_Gen_Smoother_Amesos(ml,coarsest_level,ML_AMESOS_KLU,-1, 0.0);
   }
   else {
         printf("unknown coarse grid solver %s\n",context->coarse_solve);
         exit(1);
   }
		
   ML_Gen_Solver(ml, ML_MGV, 0, coarsest_level); 

   AZ_defaults(options, params);
	
   if (ML_strcmp(context->krylov,"Cg") == 0) {
      options[AZ_solver]   = AZ_cg;
   }
   else if (ML_strcmp(context->krylov,"Bicgstab") == 0) {
      options[AZ_solver]   = AZ_bicgstab;
   }
   else if (ML_strcmp(context->krylov,"Tfqmr") == 0) {
      options[AZ_solver]   = AZ_tfqmr;
   }
   else if (ML_strcmp(context->krylov,"Gmres") == 0) {
      options[AZ_solver]   = AZ_gmres;
   }
   else {
      printf("unknown krylov method %s\n",context->krylov);
   }
   if (blocks)            ML_free(blocks);
   if (block_pde)         ML_free(block_pde);
   options[AZ_scaling]  = AZ_none;
   options[AZ_precond]  = AZ_user_precond;
   options[AZ_conv]     = AZ_r0;
   options[AZ_output]   = 1;
   options[AZ_max_iter] = context->max_outer_its;
   options[AZ_poly_ord] = 5;
   options[AZ_kspace]   = 130;
   params[AZ_tol]       = context->tol;
   options[AZ_output]   = context->output;
   ML_free(context);
	
   AZ_set_ML_preconditioner(&Pmat, Amat, ml, options); 
   setup_time = AZ_second() - start_time;
	
   xxx = (double *) malloc( leng*sizeof(double));

   for (iii = 0; iii < leng; iii++) xxx[iii] = 0.0; 
	

   /* Set x */
   /*
   there is no initguess supplied with these examples for the moment....
   */
   fp = fopen("initguessfile","r");
   if (fp != NULL) {
      fclose(fp);
      if (proc_config[AZ_node]== 0) printf("reading initial guess from file\n");
      AZ_input_msr_matrix("data_initguess.txt", update, &xxx, &garbage, N_update, 
                          proc_config);

      options[AZ_conv] = AZ_expected_values;
   }
   else if (proc_config[AZ_node]== 0) printf("taking 0 initial guess \n");

   AZ_reorder_vec(xxx, data_org, update_index, NULL);

   /* if Dirichlet BC ... put the answer in */

   for (i = 0; i < data_org[AZ_N_internal]+data_org[AZ_N_border]; i++) {
      if ( (val[i] > .99999999) && (val[i] < 1.0000001))
         xxx[i] = rhs[i];      
   }

   fp = fopen("AZ_no_multilevel.dat","r");
   scaling = AZ_scaling_create();
   start_time = AZ_second();
   if (fp != NULL) {
      fclose(fp);
      options[AZ_precond] = AZ_none;
      options[AZ_scaling] = AZ_sym_diag;
      options[AZ_ignore_scaling] = AZ_TRUE;

      options[AZ_keep_info] = 1;
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, NULL, scaling); 

/*
      options[AZ_pre_calc] = AZ_reuse;
      options[AZ_conv] = AZ_expected_values;
      if (proc_config[AZ_node] == 0) 
              printf("\n-------- Second solve with improved convergence test -----\n");
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, NULL, scaling); 
      if (proc_config[AZ_node] == 0) 
              printf("\n-------- Third solve with improved convergence test -----\n");
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, NULL, scaling); 
*/
   }
   else {
      options[AZ_keep_info] = 1;
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, Pmat, scaling); 
      options[AZ_pre_calc] = AZ_reuse;
      options[AZ_conv] = AZ_expected_values;
/*
      if (proc_config[AZ_node] == 0) 
              printf("\n-------- Second solve with improved convergence test -----\n");
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, Pmat, scaling); 
      if (proc_config[AZ_node] == 0) 
              printf("\n-------- Third solve with improved convergence test -----\n");
      AZ_iterate(xxx, rhs, options, params, status, proc_config, Amat, Pmat, scaling); 
*/
   }
   solve_time = AZ_second() - start_time;

   if (proc_config[AZ_node] == 0) 
      printf("Solve time = %e, MG Setup time = %e\n", solve_time, setup_time);

   if (proc_config[AZ_node] == 0) 
     printf("Printing out a few entries of the solution ...\n");

   for (j=0;j<Amat->data_org[AZ_N_internal]+ Amat->data_org[AZ_N_border];j++)
     if (update[j] == 7) {printf("solution(gid = %d) = %10.4e\n",
			      update[j],xxx[update_index[j]]); fflush(stdout);}
   j = AZ_gsum_int(7, proc_config); /* sync processors */
   for (j=0;j<Amat->data_org[AZ_N_internal]+ Amat->data_org[AZ_N_border];j++)
     if (update[j] == 23) {printf("solution(gid = %d) = %10.4e\n",
			      update[j],xxx[update_index[j]]); fflush(stdout);}
   j = AZ_gsum_int(7, proc_config); /* sync processors */
   for (j=0;j<Amat->data_org[AZ_N_internal]+ Amat->data_org[AZ_N_border];j++)
     if (update[j] == 47) {printf("solution(gid = %d) = %10.4e\n",
			      update[j],xxx[update_index[j]]); fflush(stdout);}
   j = AZ_gsum_int(7, proc_config); /* sync processors */
   for (j=0;j<Amat->data_org[AZ_N_internal]+ Amat->data_org[AZ_N_border];j++)
     if (update[j] == 101) {printf("solution(gid = %d) = %10.4e\n",
			      update[j],xxx[update_index[j]]); fflush(stdout);}
   j = AZ_gsum_int(7, proc_config); /* sync processors */
   for (j=0;j<Amat->data_org[AZ_N_internal]+ Amat->data_org[AZ_N_border];j++)
     if (update[j] == 171) {printf("solution(gid = %d) = %10.4e\n",
			      update[j],xxx[update_index[j]]); fflush(stdout);}

   ML_Aggregate_Destroy(&ag);
   ML_Destroy(&ml);
   AZ_free((void *) Amat->data_org);
   AZ_free((void *) Amat->val);
   AZ_free((void *) Amat->bindx);
   AZ_free((void *) update);
   AZ_free((void *) external);
   AZ_free((void *) extern_index);
   AZ_free((void *) update_index);
   AZ_scaling_destroy(&scaling);
   if (Amat  != NULL) AZ_matrix_destroy(&Amat);
   if (Pmat  != NULL) AZ_precond_destroy(&Pmat);
   free(xxx);
   free(rhs);

#ifdef ML_MPI
  MPI_Finalize();
#endif
	
  return 0;
	
}