Пример #1
0
void sample1(struct data *Afine_data, struct data *Acoarse_data,
	     struct data  *Rmat_data, struct data    *Pmat_data,
	     double *sol, double *rhs )
{
   ML  *my_ml;
   int i;
   int fine_grid, output_level = 10, N_grids = 2, grid0 = 0, grid1 = 1;
   int Nfine, Ncoarse;
   double *diagonal;

   Nfine    = Rmat_data->from_size;
   Ncoarse  = Rmat_data->to_size;
   diagonal = (double *) malloc(Nfine*sizeof(double));
   for (i = 0; i < Nfine; i++) diagonal[i] = 2.;

   fine_grid   = grid1;
   ML_Create         (&my_ml, N_grids);
   ML_Set_OutputLevel( my_ml, output_level);

   ML_Init_Amatrix      (my_ml, grid1,  Nfine, Nfine,(void *) Afine_data);
   ML_Set_Amatrix_Getrow(my_ml, grid1,  myAgetrow, my_comm, Nfine+1);
   ML_Set_Amatrix_Matvec(my_ml, grid1,  mymatvec);
   ML_Set_Amatrix_Diag  (my_ml, grid1,  Nfine, diagonal);
   ML_Gen_Smoother_Jacobi(my_ml, grid1,  ML_PRESMOOTHER, 2, ML_DEFAULT);

   ML_Init_Prolongator(my_ml, grid0, grid1, Ncoarse,Nfine,(void *)Pmat_data);
   ML_Set_Prolongator_Getrow(my_ml,  grid0, myPgetrow, my_comm, Ncoarse+1);
   ML_Set_Prolongator_Matvec(my_ml,  grid0, myinterp);

   ML_Init_Restrictor(my_ml, grid1, grid0, Nfine, Ncoarse,(void *)Rmat_data);
   ML_Set_Restrictor_Getrow(my_ml,  grid1, myRgetrow, my_comm, Nfine+1);
   ML_Set_Restrictor_Matvec(my_ml,  grid1, myrestrict);


   ML_Gen_AmatrixRAP(my_ml,grid1, grid0);
#ifdef SUPERLU
   ML_Gen_CoarseSolverSuperLU(my_ml, grid0);
#else
   ML_Gen_Smoother_Jacobi(my_ml, grid0,  ML_PRESMOOTHER, 100, ML_DEFAULT);
#endif

/* ML_Gen_Smoother_Jacobi(my_ml, grid0, ML_PRESMOOTHER, 200, ML_DEFAULT); */
/* ML_Gen_Smoother_GaussSeidel(my_ml, grid0, ML_PRESMOOTHER, 200, 1.);    */
   ML_Gen_Solver    (my_ml, 0, fine_grid, grid0);
   ML_Iterate(my_ml, sol, rhs);
   ML_Destroy(&my_ml);
   ML_free(diagonal);

}
Пример #2
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);
}