Date: 2015-10-02T22:19:21+00:00

Actual source code: gamg.c
petsc-3.6.2 2015-10-02
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      1: /*
      2:  GAMG geometric-algebric multigrid PC - Mark Adams 2011
      3:  */
      4: #include <petsc/private/matimpl.h>
      5: #include <../src/ksp/pc/impls/gamg/gamg.h>           /*I "petscpc.h" I*/
      6: #include <petsc/private/kspimpl.h>
      7: #include <../src/ksp/pc/impls/bjacobi/bjacobi.h> /* Hack to access same_local_solves */

      9: #if defined PETSC_GAMG_USE_LOG
     10: PetscLogEvent petsc_gamg_setup_events[NUM_SET];
     11: #endif

     13: #if defined PETSC_USE_LOG
     14: PetscLogEvent PC_GAMGGraph_AGG;
     15: PetscLogEvent PC_GAMGGraph_GEO;
     16: PetscLogEvent PC_GAMGCoarsen_AGG;
     17: PetscLogEvent PC_GAMGCoarsen_GEO;
     18: PetscLogEvent PC_GAMGProlongator_AGG;
     19: PetscLogEvent PC_GAMGProlongator_GEO;
     20: PetscLogEvent PC_GAMGOptProlongator_AGG;
     21: #endif

     23: #define GAMG_MAXLEVELS 30

     25: /* #define GAMG_STAGES */
     26: #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
     27: static PetscLogStage gamg_stages[GAMG_MAXLEVELS];
     28: #endif

     30: static PetscFunctionList GAMGList = 0;
     31: static PetscBool PCGAMGPackageInitialized;

     33: /* ----------------------------------------------------------------------------- */
     36: PetscErrorCode PCReset_GAMG(PC pc)
     37: {
     39:   PC_MG          *mg      = (PC_MG*)pc->data;
     40:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

     43:   if (pc_gamg->data) { /* this should not happen, cleaned up in SetUp */
     44:     PetscPrintf(PetscObjectComm((PetscObject)pc),"***[%d]%s this should not happen, cleaned up in SetUp\n",0,__FUNCT__);
     45:     PetscFree(pc_gamg->data);
     46:   }
     47:   pc_gamg->data_sz = 0;
     48:   PetscFree(pc_gamg->orig_data);
     49:   return(0);
     50: }

     52: /* -------------------------------------------------------------------------- */
     53: /*
     54:    PCGAMGCreateLevel_GAMG: create coarse op with RAP.  repartition and/or reduce number
     55:      of active processors.

     57:    Input Parameter:
     58:    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
     59:           'pc_gamg->data_sz' are changed via repartitioning/reduction.
     60:    . Amat_fine - matrix on this fine (k) level
     61:    . cr_bs - coarse block size
     62:    In/Output Parameter:
     63:    . a_P_inout - prolongation operator to the next level (k-->k-1)
     64:    . a_nactive_proc - number of active procs
     65:    Output Parameter:
     66:    . a_Amat_crs - coarse matrix that is created (k-1)
     67: */

     71: static PetscErrorCode PCGAMGCreateLevel_GAMG(PC pc,Mat Amat_fine,PetscInt cr_bs,
     72:                                   Mat *a_P_inout,Mat *a_Amat_crs,PetscMPIInt *a_nactive_proc,
     73:                                   IS * Pcolumnperm)
     74: {
     75:   PetscErrorCode  ierr;
     76:   PC_MG           *mg         = (PC_MG*)pc->data;
     77:   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
     78:   Mat             Cmat,Pold=*a_P_inout;
     79:   MPI_Comm        comm;
     80:   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
     81:   PetscInt        ncrs_eq,ncrs,f_bs;

     84:   PetscObjectGetComm((PetscObject)Amat_fine,&comm);
     85:   MPI_Comm_rank(comm, &rank);
     86:   MPI_Comm_size(comm, &size);
     87:   MatGetBlockSize(Amat_fine, &f_bs);
     88:   MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);

     90:   /* set 'ncrs' (nodes), 'ncrs_eq' (equations)*/
     91:   MatGetLocalSize(Cmat, &ncrs_eq, NULL);
     92:   if (pc_gamg->data_cell_rows>0) {
     93:     ncrs = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
     94:   } else {
     95:     PetscInt  bs;
     96:     MatGetBlockSize(Cmat, &bs);
     97:     ncrs = ncrs_eq/bs;
     98:   }

    100:   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
    101:   {
    102:     PetscInt ncrs_eq_glob;
    103:     MatGetSize(Cmat, &ncrs_eq_glob, NULL);
    104:     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)pc_gamg->min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
    105:     if (new_size == 0) new_size = 1; /* not likely, posible? */
    106:     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
    107:   }

    109:   if (Pcolumnperm) *Pcolumnperm = NULL;

    111:   if (!pc_gamg->repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
    112:   else {
    113:     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_new,ncrs_eq_new,nloc_old;
    114:     IS             is_eq_newproc,is_eq_num,is_eq_num_prim,new_eq_indices;

    116:     nloc_old = ncrs_eq/cr_bs;
    117:     if (ncrs_eq % cr_bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ncrs_eq %D not divisible by cr_bs %D",ncrs_eq,cr_bs);
    118: #if defined PETSC_GAMG_USE_LOG
    119:     PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);
    120: #endif
    121:     /* make 'is_eq_newproc' */
    122:     PetscMalloc1(size, &counts);
    123:     if (pc_gamg->repart) {
    124:       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
    125:       Mat adj;

    127:      PetscInfo3(pc,"Repartition: size (active): %D --> %D, neq = %D\n",*a_nactive_proc,new_size,ncrs_eq);

    129:       /* get 'adj' */
    130:       if (cr_bs == 1) {
    131:         MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);
    132:       } else {
    133:         /* make a scalar matrix to partition (no Stokes here) */
    134:         Mat               tMat;
    135:         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
    136:         const PetscScalar *vals;
    137:         const PetscInt    *idx;
    138:         PetscInt          *d_nnz, *o_nnz, M, N;
    139:         static PetscInt   llev = 0;
    140:         MatType           mtype;

    142:         PetscMalloc2(ncrs, &d_nnz,ncrs, &o_nnz);
    143:         MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);
    144:         MatGetSize(Cmat, &M, &N);
    145:         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
    146:           MatGetRow(Cmat,Ii,&ncols,0,0);
    147:           d_nnz[jj] = ncols/cr_bs;
    148:           o_nnz[jj] = ncols/cr_bs;
    149:           MatRestoreRow(Cmat,Ii,&ncols,0,0);
    150:           if (d_nnz[jj] > ncrs) d_nnz[jj] = ncrs;
    151:           if (o_nnz[jj] > (M/cr_bs-ncrs)) o_nnz[jj] = M/cr_bs-ncrs;
    152:         }

    154:         MatGetType(Amat_fine,&mtype);
    155:         MatCreate(comm, &tMat);
    156:         MatSetSizes(tMat, ncrs, ncrs,PETSC_DETERMINE, PETSC_DETERMINE);
    157:         MatSetType(tMat,mtype);
    158:         MatSeqAIJSetPreallocation(tMat,0,d_nnz);
    159:         MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);
    160:         PetscFree2(d_nnz,o_nnz);

    162:         for (ii = Istart_crs; ii < Iend_crs; ii++) {
    163:           PetscInt dest_row = ii/cr_bs;
    164:           MatGetRow(Cmat,ii,&ncols,&idx,&vals);
    165:           for (jj = 0; jj < ncols; jj++) {
    166:             PetscInt    dest_col = idx[jj]/cr_bs;
    167:             PetscScalar v        = 1.0;
    168:             MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);
    169:           }
    170:           MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);
    171:         }
    172:         MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);
    173:         MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);

    175:         if (llev++ == -1) {
    176:           PetscViewer viewer; char fname[32];
    177:           PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);
    178:           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
    179:           MatView(tMat, viewer);
    180:           PetscViewerDestroy(&viewer);
    181:         }

    183:         MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);

    185:         MatDestroy(&tMat);
    186:       } /* create 'adj' */

    188:       { /* partition: get newproc_idx */
    189:         char            prefix[256];
    190:         const char      *pcpre;
    191:         const PetscInt  *is_idx;
    192:         MatPartitioning mpart;
    193:         IS              proc_is;
    194:         PetscInt        targetPE;

    196:         MatPartitioningCreate(comm, &mpart);
    197:         MatPartitioningSetAdjacency(mpart, adj);
    198:         PCGetOptionsPrefix(pc, &pcpre);
    199:         PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");
    200:         PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);
    201:         MatPartitioningSetFromOptions(mpart);
    202:         MatPartitioningSetNParts(mpart, new_size);
    203:         MatPartitioningApply(mpart, &proc_is);
    204:         MatPartitioningDestroy(&mpart);

    206:         /* collect IS info */
    207:         PetscMalloc1(ncrs_eq, &newproc_idx);
    208:         ISGetIndices(proc_is, &is_idx);
    209:         targetPE = 1; /* bring to "front" of machine */
    210:         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
    211:         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
    212:           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
    213:             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
    214:           }
    215:         }
    216:         ISRestoreIndices(proc_is, &is_idx);
    217:         ISDestroy(&proc_is);
    218:       }
    219:       MatDestroy(&adj);

    221:       ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);
    222:       PetscFree(newproc_idx);
    223:     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */

    225:       PetscInt rfactor,targetPE;
    226:       /* find factor */
    227:       if (new_size == 1) rfactor = size; /* easy */
    228:       else {
    229:         PetscReal best_fact = 0.;
    230:         jj = -1;
    231:         for (kk = 1 ; kk <= size ; kk++) {
    232:           if (size%kk==0) { /* a candidate */
    233:             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
    234:             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
    235:             if (fact > best_fact) {
    236:               best_fact = fact; jj = kk;
    237:             }
    238:           }
    239:         }
    240:         if (jj != -1) rfactor = jj;
    241:         else rfactor = 1; /* does this happen .. a prime */
    242:       }
    243:       new_size = size/rfactor;

    245:       if (new_size==nactive) {
    246:         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
    247:         PetscFree(counts);
    248:         PetscInfo2(pc,"Aggregate processors noop: new_size=%D, neq(loc)=%D\n",new_size,ncrs_eq);
    249:         return(0);
    250:       }

    252:       PetscInfo1(pc,"Number of equations (loc) %D with simple aggregation\n",ncrs_eq);
    253:       targetPE = rank/rfactor;
    254:       ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);
    255:     } /* end simple 'is_eq_newproc' */

    257:     /*
    258:      Create an index set from the is_eq_newproc index set to indicate the mapping TO
    259:      */
    260:     ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);
    261:     is_eq_num_prim = is_eq_num;
    262:     /*
    263:       Determine how many equations/vertices are assigned to each processor
    264:      */
    265:     ISPartitioningCount(is_eq_newproc, size, counts);
    266:     ncrs_eq_new = counts[rank];
    267:     ISDestroy(&is_eq_newproc);
    268:     ncrs_new = ncrs_eq_new/cr_bs; /* eqs */

    270:     PetscFree(counts);
    271: #if defined PETSC_GAMG_USE_LOG
    272:     PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);
    273: #endif
    274:     /* data movement scope -- this could be moved to subclasses so that we don't try to cram all auxilary data into some complex abstracted thing */
    275:     {
    276:     Vec            src_crd, dest_crd;
    277:     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
    278:     VecScatter     vecscat;
    279:     PetscScalar    *array;
    280:     IS isscat;

    282:     /* move data (for primal equations only) */
    283:     /* Create a vector to contain the newly ordered element information */
    284:     VecCreate(comm, &dest_crd);
    285:     VecSetSizes(dest_crd, node_data_sz*ncrs_new, PETSC_DECIDE);
    286:     VecSetType(dest_crd,VECSTANDARD); /* this is needed! */
    287:     /*
    288:      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
    289:      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
    290:      */
    291:     PetscMalloc1(ncrs*node_data_sz, &tidx);
    292:     ISGetIndices(is_eq_num_prim, &idx);
    293:     for (ii=0,jj=0; ii<ncrs; ii++) {
    294:       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
    295:       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
    296:     }
    297:     ISRestoreIndices(is_eq_num_prim, &idx);
    298:     ISCreateGeneral(comm, node_data_sz*ncrs, tidx, PETSC_COPY_VALUES, &isscat);
    299:     PetscFree(tidx);
    300:     /*
    301:      Create a vector to contain the original vertex information for each element
    302:      */
    303:     VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs, &src_crd);
    304:     for (jj=0; jj<ndata_cols; jj++) {
    305:       const PetscInt stride0=ncrs*pc_gamg->data_cell_rows;
    306:       for (ii=0; ii<ncrs; ii++) {
    307:         for (kk=0; kk<ndata_rows; kk++) {
    308:           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
    309:           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
    310:           VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);
    311:         }
    312:       }
    313:     }
    314:     VecAssemblyBegin(src_crd);
    315:     VecAssemblyEnd(src_crd);
    316:     /*
    317:       Scatter the element vertex information (still in the original vertex ordering)
    318:       to the correct processor
    319:     */
    320:     VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);
    321:     ISDestroy(&isscat);
    322:     VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);
    323:     VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);
    324:     VecScatterDestroy(&vecscat);
    325:     VecDestroy(&src_crd);
    326:     /*
    327:       Put the element vertex data into a new allocation of the gdata->ele
    328:     */
    329:     PetscFree(pc_gamg->data);
    330:     PetscMalloc1(node_data_sz*ncrs_new, &pc_gamg->data);

    332:     pc_gamg->data_sz = node_data_sz*ncrs_new;
    333:     strideNew        = ncrs_new*ndata_rows;

    335:     VecGetArray(dest_crd, &array);
    336:     for (jj=0; jj<ndata_cols; jj++) {
    337:       for (ii=0; ii<ncrs_new; ii++) {
    338:         for (kk=0; kk<ndata_rows; kk++) {
    339:           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
    340:           pc_gamg->data[ix] = PetscRealPart(array[jx]);
    341:         }
    342:       }
    343:     }
    344:     VecRestoreArray(dest_crd, &array);
    345:     VecDestroy(&dest_crd);
    346:     }
    347:     /* move A and P (columns) with new layout */
    348: #if defined PETSC_GAMG_USE_LOG
    349:     PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);
    350: #endif

    352:     /*
    353:       Invert for MatGetSubMatrix
    354:     */
    355:     ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);
    356:     ISSort(new_eq_indices); /* is this needed? */
    357:     ISSetBlockSize(new_eq_indices, cr_bs);
    358:     if (is_eq_num != is_eq_num_prim) {
    359:       ISDestroy(&is_eq_num_prim); /* could be same as 'is_eq_num' */
    360:     }
    361:     if (Pcolumnperm) {
    362:       PetscObjectReference((PetscObject)new_eq_indices);
    363:       *Pcolumnperm = new_eq_indices;
    364:     }
    365:     ISDestroy(&is_eq_num);
    366: #if defined PETSC_GAMG_USE_LOG
    367:     PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);
    368:     PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);
    369: #endif
    370:     /* 'a_Amat_crs' output */
    371:     {
    372:       Mat mat;
    373:       MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);
    374:       *a_Amat_crs = mat;

    376:       if (!PETSC_TRUE) {
    377:         PetscInt cbs, rbs;
    378:         MatGetBlockSizes(Cmat, &rbs, &cbs);
    379:         PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);
    380:         MatGetBlockSizes(mat, &rbs, &cbs);
    381:         PetscPrintf(MPI_COMM_SELF,"[%d]%s New Mat rbs=%d cbs=%d cr_bs=%d\n",rank,__FUNCT__,rbs,cbs,cr_bs);
    382:       }
    383:     }
    384:     MatDestroy(&Cmat);

    386: #if defined PETSC_GAMG_USE_LOG
    387:     PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);
    388: #endif
    389:     /* prolongator */
    390:     {
    391:       IS       findices;
    392:       PetscInt Istart,Iend;
    393:       Mat      Pnew;
    394:       MatGetOwnershipRange(Pold, &Istart, &Iend);
    395: #if defined PETSC_GAMG_USE_LOG
    396:       PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);
    397: #endif
    398:       ISCreateStride(comm,Iend-Istart,Istart,1,&findices);
    399:       ISSetBlockSize(findices,f_bs);
    400:       MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);
    401:       ISDestroy(&findices);

    403:       if (!PETSC_TRUE) {
    404:         PetscInt cbs, rbs;
    405:         MatGetBlockSizes(Pold, &rbs, &cbs);
    406:         PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);
    407:         MatGetBlockSizes(Pnew, &rbs, &cbs);
    408:         PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);
    409:       }
    410: #if defined PETSC_GAMG_USE_LOG
    411:       PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);
    412: #endif
    413:       MatDestroy(a_P_inout);

    415:       /* output - repartitioned */
    416:       *a_P_inout = Pnew;
    417:     }
    418:     ISDestroy(&new_eq_indices);

    420:     *a_nactive_proc = new_size; /* output */
    421:   }

    423:   /* outout matrix data */
    424:   if (!PETSC_TRUE) {
    425:     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
    426:     if (llev==0) {
    427:       sprintf(fname,"Cmat_%d.m",llev++);
    428:       PetscViewerASCIIOpen(comm,fname,&viewer);
    429:       PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);
    430:       MatView(Amat_fine, viewer);
    431:       PetscViewerDestroy(&viewer);
    432:     }
    433:     sprintf(fname,"Cmat_%d.m",llev++);
    434:     PetscViewerASCIIOpen(comm,fname,&viewer);
    435:     PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);
    436:     MatView(Cmat, viewer);
    437:     PetscViewerDestroy(&viewer);
    438:   }
    439:   return(0);
    440: }

    442: /* -------------------------------------------------------------------------- */
    443: /*
    444:    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
    445:                     by setting data structures and options.

    447:    Input Parameter:
    448: .  pc - the preconditioner context

    450: */
    453: PetscErrorCode PCSetUp_GAMG(PC pc)
    454: {
    456:   PC_MG          *mg      = (PC_MG*)pc->data;
    457:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
    458:   Mat            Pmat     = pc->pmat;
    459:   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
    460:   MPI_Comm       comm;
    461:   PetscMPIInt    rank,size,nactivepe;
    462:   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
    463:   PetscReal      emaxs[GAMG_MAXLEVELS];
    464:   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
    465:   PetscLogDouble nnz0=0.,nnztot=0.;
    466:   MatInfo        info;

    469:   PetscObjectGetComm((PetscObject)pc,&comm);
    470:   MPI_Comm_rank(comm,&rank);
    471:   MPI_Comm_size(comm,&size);

    473:   if (pc_gamg->setup_count++ > 0) {
    474:     if ((PetscBool)(!pc_gamg->reuse_prol)) {
    475:       /* reset everything */
    476:       PCReset_MG(pc);
    477:       pc->setupcalled = 0;
    478:     } else {
    479:       PC_MG_Levels **mglevels = mg->levels;
    480:       /* just do Galerkin grids */
    481:       Mat          B,dA,dB;

    483:      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
    484:       if (pc_gamg->Nlevels > 1) {
    485:         /* currently only handle case where mat and pmat are the same on coarser levels */
    486:         KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB);
    487:         /* (re)set to get dirty flag */
    488:         KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB);

    490:         for (level=pc_gamg->Nlevels-2; level>=0; level--) {
    491:           /* the first time through the matrix structure has changed from repartitioning */
    492:           if (pc_gamg->setup_count==2) {
    493:             MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);
    494:             MatDestroy(&mglevels[level]->A);

    496:             mglevels[level]->A = B;
    497:           } else {
    498:             KSPGetOperators(mglevels[level]->smoothd,NULL,&B);
    499:             MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);
    500:           }
    501:           KSPSetOperators(mglevels[level]->smoothd,B,B);
    502:           dB   = B;
    503:         }
    504:       }

    506:       PCSetUp_MG(pc);

    508:       return(0);
    509:     }
    510:   }

    512:   if (!pc_gamg->data) {
    513:     if (pc_gamg->orig_data) {
    514:       MatGetBlockSize(Pmat, &bs);
    515:       MatGetLocalSize(Pmat, &qq, NULL);

    517:       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
    518:       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
    519:       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;

    521:       PetscMalloc1(pc_gamg->data_sz, &pc_gamg->data);
    522:       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
    523:     } else {
    524:       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
    525:       pc_gamg->ops->createdefaultdata(pc,Pmat);
    526:     }
    527:   }

    529:   /* cache original data for reuse */
    530:   if (!pc_gamg->orig_data && (PetscBool)(!pc_gamg->reuse_prol)) {
    531:     PetscMalloc1(pc_gamg->data_sz, &pc_gamg->orig_data);
    532:     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
    533:     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
    534:     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
    535:   }

    537:   /* get basic dims */
    538:   MatGetBlockSize(Pmat, &bs);
    539:   MatGetSize(Pmat, &M, &qq);

    541:   MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info); /* global reduction */
    542:   nnz0   = info.nz_used;
    543:   nnztot = info.nz_used;
    544:   PetscInfo6(pc,"level %d) N=%D, n data rows=%d, n data cols=%d, nnz/row (ave)=%d, np=%d\n",
    545:                     0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
    546:                     (int)(nnz0/(PetscReal)M+0.5),size);
    547:

    549:   /* Get A_i and R_i */
    550:   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
    551:        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);
    552:        level++) {
    553:     pc_gamg->current_level = level;
    554:     level1 = level + 1;
    555: #if defined PETSC_GAMG_USE_LOG
    556:     PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);
    557: #if (defined GAMG_STAGES)
    558:     PetscLogStagePush(gamg_stages[level]);
    559: #endif
    560: #endif
    561:     { /* construct prolongator */
    562:       Mat              Gmat;
    563:       PetscCoarsenData *agg_lists;
    564:       Mat              Prol11;

    566:       pc_gamg->ops->graph(pc,Aarr[level], &Gmat);
    567:       pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);
    568:       pc_gamg->ops->prolongator(pc,Aarr[level],Gmat,agg_lists,&Prol11);

    570:       /* could have failed to create new level */
    571:       if (Prol11) {
    572:         /* get new block size of coarse matrices */
    573:         MatGetBlockSizes(Prol11, NULL, &bs);

    575:         if (pc_gamg->ops->optprolongator) {
    576:           /* smooth */
    577:           pc_gamg->ops->optprolongator(pc, Aarr[level], &Prol11);
    578:         }

    580:         Parr[level1] = Prol11;
    581:       } else Parr[level1] = NULL;

    583:       if (pc_gamg->use_aggs_in_gasm) {
    584:         PetscInt bs;
    585:         MatGetBlockSizes(Prol11, &bs, NULL);
    586:         PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);
    587:       }

    589:       MatDestroy(&Gmat);
    590:       PetscCDDestroy(agg_lists);
    591:     } /* construct prolongator scope */
    592: #if defined PETSC_GAMG_USE_LOG
    593:     PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);
    594: #endif
    595:     /* cache eigen estimate */
    596:     if (pc_gamg->emax_id != -1) {
    597:       PetscBool flag;
    598:       PetscObjectComposedDataGetReal((PetscObject)Aarr[level], pc_gamg->emax_id, emaxs[level], flag);
    599:       if (!flag) emaxs[level] = -1.;
    600:     } else emaxs[level] = -1.;
    601:     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
    602:     if (!Parr[level1]) {
    603:        PetscInfo1(pc,"Stop gridding, level %D\n",level);
    604: #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
    605:       PetscLogStagePop();
    606: #endif
    607:       break;
    608:     }
    609: #if defined PETSC_GAMG_USE_LOG
    610:     PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);
    611: #endif

    613:     pc_gamg->ops->createlevel(pc, Aarr[level], bs,&Parr[level1], &Aarr[level1], &nactivepe, NULL);

    615: #if defined PETSC_GAMG_USE_LOG
    616:     PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);
    617: #endif
    618:     MatGetSize(Aarr[level1], &M, &qq);

    620:     MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);
    621:     nnztot += info.nz_used;
    622:     PetscInfo5(pc,"%d) N=%D, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",level1,M,pc_gamg->data_cell_cols,(int)(info.nz_used/(PetscReal)M),nactivepe);

    624: #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
    625:     PetscLogStagePop();
    626: #endif
    627:     /* stop if one node or one proc -- could pull back for singular problems */
    628:     if ( (pc_gamg->data_cell_cols && M/pc_gamg->data_cell_cols < 2) || (!pc_gamg->data_cell_cols && M/bs < 2) ) {
    629:        PetscInfo2(pc,"HARD stop of coarsening on level %D.  Grid too small: %D block nodes\n",level,M/bs);
    630:       level++;
    631:       break;
    632:     }
    633:   } /* levels */
    634:   PetscFree(pc_gamg->data);

    636:   PetscInfo2(pc,"%D levels, grid complexity = %g\n",level+1,nnztot/nnz0);
    637:   pc_gamg->Nlevels = level + 1;
    638:   fine_level       = level;
    639:   PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);

    641:   /* simple setup */
    642:   if (!PETSC_TRUE) {
    643:     PC_MG_Levels **mglevels = mg->levels;
    644:     for (lidx=0,level=pc_gamg->Nlevels-1;
    645:          lidx<fine_level;
    646:          lidx++, level--) {
    647:       PCMGSetInterpolation(pc, lidx+1, Parr[level]);
    648:       KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level]);
    649:       MatDestroy(&Parr[level]);
    650:       MatDestroy(&Aarr[level]);
    651:     }
    652:     KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0]);

    654:     PCSetUp_MG(pc);
    655:   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
    656:     /* set default smoothers & set operators */
    657:     for (lidx = 1, level = pc_gamg->Nlevels-2;
    658:          lidx <= fine_level;
    659:          lidx++, level--) {
    660:       KSP smoother;
    661:       PC  subpc;

    663:       PCMGGetSmoother(pc, lidx, &smoother);
    664:       KSPGetPC(smoother, &subpc);

    666:       KSPSetNormType(smoother, KSP_NORM_NONE);
    667:       /* set ops */
    668:       KSPSetOperators(smoother, Aarr[level], Aarr[level]);
    669:       PCMGSetInterpolation(pc, lidx, Parr[level+1]);

    671:       /* set defaults */
    672:       KSPSetType(smoother, KSPCHEBYSHEV);

    674:       /* set blocks for GASM smoother that uses the 'aggregates' */
    675:       if (pc_gamg->use_aggs_in_gasm) {
    676:         PetscInt sz;
    677:         IS       *is;

    679:         sz   = nASMBlocksArr[level];
    680:         is   = ASMLocalIDsArr[level];
    681:         PCSetType(subpc, PCGASM);
    682:         PCGASMSetOverlap(subpc, 0);
    683:         if (sz==0) {
    684:           IS       is;
    685:           PetscInt my0,kk;
    686:           MatGetOwnershipRange(Aarr[level], &my0, &kk);
    687:           ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);
    688:           PCGASMSetSubdomains(subpc, 1, &is, NULL);
    689:           ISDestroy(&is);
    690:         } else {
    691:           PetscInt kk;
    692:           PCGASMSetSubdomains(subpc, sz, is, NULL);
    693:           for (kk=0; kk<sz; kk++) {
    694:             ISDestroy(&is[kk]);
    695:           }
    696:           PetscFree(is);
    697:         }
    698:         ASMLocalIDsArr[level] = NULL;
    699:         nASMBlocksArr[level]  = 0;
    700:         PCGASMSetType(subpc, PC_GASM_BASIC);
    701:       } else {
    702:         PCSetType(subpc, PCSOR);
    703:       }
    704:     }
    705:     {
    706:       /* coarse grid */
    707:       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
    708:       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
    709:       PCMGGetSmoother(pc, lidx, &smoother);
    710:       KSPSetOperators(smoother, Lmat, Lmat);
    711:       KSPSetNormType(smoother, KSP_NORM_NONE);
    712:       KSPGetPC(smoother, &subpc);
    713:       PCSetType(subpc, PCBJACOBI);
    714:       PCSetUp(subpc);
    715:       PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);
    716:       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
    717:       KSPGetPC(k2[0],&pc2);
    718:       PCSetType(pc2, PCLU);
    719:       PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);
    720:       KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);
    721:       /* This flag gets reset by PCBJacobiGetSubKSP(), but our BJacobi really does the same algorithm everywhere (and in
    722:        * fact, all but one process will have zero dofs), so we reset the flag to avoid having PCView_BJacobi attempt to
    723:        * view every subdomain as though they were different. */
    724:       ((PC_BJacobi*)subpc->data)->same_local_solves = PETSC_TRUE;
    725:     }

    727:     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
    728:     PetscObjectOptionsBegin((PetscObject)pc);
    729:     PCSetFromOptions_MG(PetscOptionsObject,pc);
    730:     PetscOptionsEnd();
    731:     if (!mg->galerkin) SETERRQ(comm,PETSC_ERR_USER,"PCGAMG must use Galerkin for coarse operators.");
    732:     if (mg->galerkin == 1) mg->galerkin = 2;

    734:     /* create cheby smoothers */
    735:     for (lidx = 1, level = pc_gamg->Nlevels-2; lidx <= fine_level; lidx++, level--) {
    736:       KSP       smoother;
    737:       PetscBool flag,flag2;
    738:       PC        subpc;

    740:       PCMGGetSmoother(pc, lidx, &smoother);
    741:       KSPGetPC(smoother, &subpc);

    743:       /* do my own cheby */
    744:       PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);
    745:       if (0 && flag) {
    746:         PetscReal emax, emin;
    747:         PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);
    748:         PetscObjectTypeCompare((PetscObject)subpc, PCSOR, &flag2);
    749:         /* eigen estimate only for diagnal PC but lets acccept SOR because it is close and safe (always lower) */
    750:         if ((flag||flag2) && (emax=emaxs[level]) > 0.0) {
    751:           PetscInt N1, N0;
    752:           emax=emaxs[level];
    753:           MatGetSize(Aarr[level], &N1, NULL);
    754:           MatGetSize(Aarr[level+1], &N0, NULL);
    755:           emin  = emax * pc_gamg->eigtarget[0];
    756:           emax *= pc_gamg->eigtarget[1];
    757:           KSPChebyshevSetEigenvalues(smoother, emax, emin);
    758:         }
    759:       } /* setup checby flag */
    760:     } /* non-coarse levels */

    762:     /* clean up */
    763:     for (level=1; level<pc_gamg->Nlevels; level++) {
    764:       MatDestroy(&Parr[level]);
    765:       MatDestroy(&Aarr[level]);
    766:     }

    768:     PCSetUp_MG(pc);
    769:   } else {
    770:     KSP smoother;
    771:     PetscInfo(pc,"One level solver used (system is seen as DD). Using default solver.\n");
    772:     PCMGGetSmoother(pc, 0, &smoother);
    773:     KSPSetOperators(smoother, Aarr[0], Aarr[0]);
    774:     KSPSetType(smoother, KSPPREONLY);
    775:     PCSetUp_MG(pc);
    776:   }
    777:   return(0);
    778: }

    780: /* ------------------------------------------------------------------------- */
    781: /*
    782:  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
    783:    that was created with PCCreate_GAMG().

    785:    Input Parameter:
    786: .  pc - the preconditioner context

    788:    Application Interface Routine: PCDestroy()
    789: */
    792: PetscErrorCode PCDestroy_GAMG(PC pc)
    793: {
    795:   PC_MG          *mg     = (PC_MG*)pc->data;
    796:   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;

    799:   PCReset_GAMG(pc);
    800:   if (pc_gamg->ops->destroy) {
    801:     (*pc_gamg->ops->destroy)(pc);
    802:   }
    803:   PetscFree(pc_gamg->ops);
    804:   PetscFree(pc_gamg->gamg_type_name);
    805:   PetscFree(pc_gamg);
    806:   PCDestroy_MG(pc);
    807:   return(0);
    808: }

    813: /*@
    814:    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via processor reduction.

    816:    Logically Collective on PC

    818:    Input Parameters:
    819: +  pc - the preconditioner context
    820: -  n - the number of equations

    823:    Options Database Key:
    824: .  -pc_gamg_process_eq_limit <limit>

    826:    Level: intermediate

    828:    Concepts: Unstructured multigrid preconditioner

    830: .seealso: PCGAMGSetCoarseEqLim()
    831: @*/
    832: PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
    833: {

    838:   PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));
    839:   return(0);
    840: }

    844: static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
    845: {
    846:   PC_MG   *mg      = (PC_MG*)pc->data;
    847:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    850:   if (n>0) pc_gamg->min_eq_proc = n;
    851:   return(0);
    852: }

    856: /*@
    857:    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.

    859:  Collective on PC

    861:    Input Parameters:
    862: +  pc - the preconditioner context
    863: -  n - maximum number of equations to aim for

    865:    Options Database Key:
    866: .  -pc_gamg_coarse_eq_limit <limit>

    868:    Level: intermediate

    870:    Concepts: Unstructured multigrid preconditioner

    872: .seealso: PCGAMGSetProcEqLim()
    873: @*/
    874: PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
    875: {

    880:   PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));
    881:   return(0);
    882: }

    886: static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
    887: {
    888:   PC_MG   *mg      = (PC_MG*)pc->data;
    889:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    892:   if (n>0) pc_gamg->coarse_eq_limit = n;
    893:   return(0);
    894: }

    898: /*@
    899:    PCGAMGSetRepartitioning - Repartition the coarse grids

    901:    Collective on PC

    903:    Input Parameters:
    904: +  pc - the preconditioner context
    905: -  n - PETSC_TRUE or PETSC_FALSE

    907:    Options Database Key:
    908: .  -pc_gamg_repartition <true,false>

    910:    Level: intermediate

    912:    Concepts: Unstructured multigrid preconditioner

    914: .seealso: ()
    915: @*/
    916: PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
    917: {

    922:   PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));
    923:   return(0);
    924: }

    928: static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
    929: {
    930:   PC_MG   *mg      = (PC_MG*)pc->data;
    931:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    934:   pc_gamg->repart = n;
    935:   return(0);
    936: }

    940: /*@
    941:    PCGAMGSetReuseInterpolation - Reuse prolongation when rebuilding preconditioner

    943:    Collective on PC

    945:    Input Parameters:
    946: +  pc - the preconditioner context
    947: -  n - PETSC_TRUE or PETSC_FALSE

    949:    Options Database Key:
    950: .  -pc_gamg_reuse_interpolation <true,false>

    952:    Level: intermediate

    954:    Concepts: Unstructured multigrid preconditioner

    956: .seealso: ()
    957: @*/
    958: PetscErrorCode PCGAMGSetReuseInterpolation(PC pc, PetscBool n)
    959: {

    964:   PetscTryMethod(pc,"PCGAMGSetReuseInterpolation_C",(PC,PetscBool),(pc,n));
    965:   return(0);
    966: }

    970: static PetscErrorCode PCGAMGSetReuseInterpolation_GAMG(PC pc, PetscBool n)
    971: {
    972:   PC_MG   *mg      = (PC_MG*)pc->data;
    973:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    976:   pc_gamg->reuse_prol = n;
    977:   return(0);
    978: }

    982: /*@
    983:    PCGAMGSetUseASMAggs -

    985:    Collective on PC

    987:    Input Parameters:
    988: .  pc - the preconditioner context

    991:    Options Database Key:
    992: .  -pc_gamg_use_agg_gasm

    994:    Level: intermediate

    996:    Concepts: Unstructured multigrid preconditioner

    998: .seealso: ()
    999: @*/
    1000: PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
    1001: {

    1006:   PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));
    1007:   return(0);
    1008: }

    1012: static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
    1013: {
    1014:   PC_MG   *mg      = (PC_MG*)pc->data;
    1015:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    1018:   pc_gamg->use_aggs_in_gasm = n;
    1019:   return(0);
    1020: }

    1024: /*@
    1025:    PCGAMGSetNlevels -  Sets the maximum number of levels PCGAMG will use

    1027:    Not collective on PC

    1029:    Input Parameters:
    1030: +  pc - the preconditioner
    1031: -  n - the maximum number of levels to use

    1033:    Options Database Key:
    1034: .  -pc_mg_levels

    1036:    Level: intermediate

    1038:    Concepts: Unstructured multigrid preconditioner

    1040: .seealso: ()
    1041: @*/
    1042: PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
    1043: {

    1048:   PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));
    1049:   return(0);
    1050: }

    1054: static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
    1055: {
    1056:   PC_MG   *mg      = (PC_MG*)pc->data;
    1057:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    1060:   pc_gamg->Nlevels = n;
    1061:   return(0);
    1062: }

    1066: /*@
    1067:    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph

    1069:    Not collective on PC

    1071:    Input Parameters:
    1072: +  pc - the preconditioner context
    1073: -  threshold - the threshold value, 0.0 means keep all nonzero entries in the graph; negative means keep even zero entries in the graph

    1075:    Options Database Key:
    1076: .  -pc_gamg_threshold <threshold>

    1078:    Level: intermediate

    1080:    Concepts: Unstructured multigrid preconditioner

    1082: .seealso: ()
    1083: @*/
    1084: PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
    1085: {

    1090:   PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));
    1091:   return(0);
    1092: }

    1096: static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
    1097: {
    1098:   PC_MG   *mg      = (PC_MG*)pc->data;
    1099:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    1102:   pc_gamg->threshold = n;
    1103:   return(0);
    1104: }

    1108: /*@
    1109:    PCGAMGSetType - Set solution method

    1111:    Collective on PC

    1113:    Input Parameters:
    1114: +  pc - the preconditioner context
    1115: -  type - PCGAMGAGG, PCGAMGGEO, or PCGAMGCLASSICAL

    1117:    Options Database Key:
    1118: .  -pc_gamg_type <agg,geo,classical>

    1120:    Level: intermediate

    1122:    Concepts: Unstructured multigrid preconditioner

    1124: .seealso: PCGAMGGetType(), PCGAMG
    1125: @*/
    1126: PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
    1127: {

    1132:   PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));
    1133:   return(0);
    1134: }

    1138: /*@
    1139:    PCGAMGGetType - Get solution method

    1141:    Collective on PC

    1143:    Input Parameter:
    1144: .  pc - the preconditioner context

    1146:    Output Parameter:
    1147: .  type - the type of algorithm used

    1149:    Level: intermediate

    1151:    Concepts: Unstructured multigrid preconditioner

    1153: .seealso: PCGAMGSetType(), PCGAMGType
    1154: @*/
    1155: PetscErrorCode PCGAMGGetType(PC pc, PCGAMGType *type)
    1156: {

    1161:   PetscUseMethod(pc,"PCGAMGGetType_C",(PC,PCGAMGType*),(pc,type));
    1162:   return(0);
    1163: }

    1167: static PetscErrorCode PCGAMGGetType_GAMG(PC pc, PCGAMGType *type)
    1168: {
    1169:   PC_MG          *mg      = (PC_MG*)pc->data;
    1170:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1173:   *type = pc_gamg->type;
    1174:   return(0);
    1175: }

    1179: static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
    1180: {
    1181:   PetscErrorCode ierr,(*r)(PC);
    1182:   PC_MG          *mg      = (PC_MG*)pc->data;
    1183:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1186:   pc_gamg->type = type;
    1187:   PetscFunctionListFind(GAMGList,type,&r);
    1188:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
    1189:   if (pc_gamg->ops->destroy) {
    1190:     (*pc_gamg->ops->destroy)(pc);
    1191:     PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));
    1192:     pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
    1193:     /* cleaning up common data in pc_gamg - this should disapear someday */
    1194:     pc_gamg->data_cell_cols = 0;
    1195:     pc_gamg->data_cell_rows = 0;
    1196:     pc_gamg->orig_data_cell_cols = 0;
    1197:     pc_gamg->orig_data_cell_rows = 0;
    1198:     PetscFree(pc_gamg->data);
    1199:     pc_gamg->data_sz = 0;
    1200:   }
    1201:   PetscFree(pc_gamg->gamg_type_name);
    1202:   PetscStrallocpy(type,&pc_gamg->gamg_type_name);
    1203:   (*r)(pc);
    1204:   return(0);
    1205: }

    1209: static PetscErrorCode PCView_GAMG(PC pc,PetscViewer viewer)
    1210: {
    1212:   PC_MG          *mg      = (PC_MG*)pc->data;
    1213:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1216:   PetscViewerASCIIPrintf(viewer,"    GAMG specific options\n");
    1217:   PetscViewerASCIIPrintf(viewer,"      Threshold for dropping small values from graph %g\n",(double)pc_gamg->threshold);
    1218:   if (pc_gamg->ops->view) {
    1219:     (*pc_gamg->ops->view)(pc,viewer);
    1220:   }
    1221:   return(0);
    1222: }

    1226: PetscErrorCode PCSetFromOptions_GAMG(PetscOptions *PetscOptionsObject,PC pc)
    1227: {
    1229:   PC_MG          *mg      = (PC_MG*)pc->data;
    1230:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
    1231:   PetscBool      flag;
    1232:   PetscInt       two   = 2;
    1233:   MPI_Comm       comm;

    1236:   PetscObjectGetComm((PetscObject)pc,&comm);
    1237:   PetscOptionsHead(PetscOptionsObject,"GAMG options");
    1238:   {
    1239:     char tname[256];
    1240:     PetscOptionsFList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, pc_gamg->gamg_type_name, tname, sizeof(tname), &flag);
    1241:     if (flag) {
    1242:       PCGAMGSetType(pc,tname);
    1243:     }
    1244:     PetscOptionsBool("-pc_gamg_repartition","Repartion coarse grids","PCGAMGRepartitioning",pc_gamg->repart,&pc_gamg->repart,NULL);
    1245:     PetscOptionsBool("-pc_gamg_reuse_interpolation","Reuse prolongation operator","PCGAMGReuseInterpolation",pc_gamg->reuse_prol,&pc_gamg->reuse_prol,NULL);
    1246:     PetscOptionsBool("-pc_gamg_use_agg_gasm","Use aggregation agragates for GASM smoother","PCGAMGUseASMAggs",pc_gamg->use_aggs_in_gasm,&pc_gamg->use_aggs_in_gasm,NULL);
    1247:     PetscOptionsInt("-pc_gamg_process_eq_limit","Limit (goal) on number of equations per process on coarse grids","PCGAMGSetProcEqLim",pc_gamg->min_eq_proc,&pc_gamg->min_eq_proc,NULL);
    1248:     PetscOptionsInt("-pc_gamg_coarse_eq_limit","Limit on number of equations for the coarse grid","PCGAMGSetCoarseEqLim",pc_gamg->coarse_eq_limit,&pc_gamg->coarse_eq_limit,NULL);
    1249:     PetscOptionsReal("-pc_gamg_threshold","Relative threshold to use for dropping edges in aggregation graph","PCGAMGSetThreshold",pc_gamg->threshold,&pc_gamg->threshold,&flag);
    1250:     PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);
    1251:     PetscOptionsInt("-pc_mg_levels","Set number of MG levels","PCGAMGSetNlevels",pc_gamg->Nlevels,&pc_gamg->Nlevels,NULL);

    1253:     /* set options for subtype */
    1254:     if (pc_gamg->ops->setfromoptions) {(*pc_gamg->ops->setfromoptions)(PetscOptionsObject,pc);}
    1255:   }
    1256:   PetscOptionsTail();
    1257:   return(0);
    1258: }

    1260: /* -------------------------------------------------------------------------- */
    1261: /*MC
    1262:      PCGAMG - Geometric algebraic multigrid (AMG) preconditioner

    1264:    Options Database Keys:
    1265:    Multigrid options(inherited)
    1266: +  -pc_mg_cycles <v>: v or w (PCMGSetCycleType())
    1267: .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
    1268: .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
    1269: -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade

    1272:   Notes: In order to obtain good performance for PCGAMG for vector valued problems you must
    1273: $       Call MatSetBlockSize() to indicate the number of degrees of freedom per grid point
    1274: $       Call MatSetNearNullSpace() (or PCSetCoordinates() if solving the equations of elasticity) to indicate the near null space of the operator
    1275: $       See the Users Manual Chapter 4 for more details

    1277:   Level: intermediate

    1279:   Concepts: algebraic multigrid

    1281: .seealso:  PCCreate(), PCSetType(), MatSetBlockSize(), PCMGType, PCSetCoordinates(), MatSetNearNullSpace(), PCGAMGSetType(), PCGAMGAGG, PCGAMGGEO, PCGAMGCLASSICAL, PCGAMGSetProcEqLim(),
    1282:            PCGAMGSetCoarseEqLim(), PCGAMGSetRepartitioning(), PCGAMGRegister(), PCGAMGSetReuseInterpolation(), PCGAMGSetUseASMAggs(), PCGAMGSetNlevels(), PCGAMGSetThreshold(), PCGAMGGetType()
    1283: M*/

    1287: PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
    1288: {
    1290:   PC_GAMG        *pc_gamg;
    1291:   PC_MG          *mg;

    1294:   /* register AMG type */
    1295:   PCGAMGInitializePackage();

    1297:   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
    1298:   PCSetType(pc, PCMG);
    1299:   PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);

    1301:   /* create a supporting struct and attach it to pc */
    1302:   PetscNewLog(pc,&pc_gamg);
    1303:   mg           = (PC_MG*)pc->data;
    1304:   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally from PCMG by GAMG code */
    1305:   mg->innerctx = pc_gamg;

    1307:   PetscNewLog(pc,&pc_gamg->ops);

    1309:   pc_gamg->setup_count = 0;
    1310:   /* these should be in subctx but repartitioning needs simple arrays */
    1311:   pc_gamg->data_sz = 0;
    1312:   pc_gamg->data    = 0;

    1314:   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
    1315:   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
    1316:   pc->ops->setup          = PCSetUp_GAMG;
    1317:   pc->ops->reset          = PCReset_GAMG;
    1318:   pc->ops->destroy        = PCDestroy_GAMG;
    1319:   mg->view                = PCView_GAMG;

    1321:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);
    1322:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);
    1323:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);
    1324:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseInterpolation_C",PCGAMGSetReuseInterpolation_GAMG);
    1325:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);
    1326:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);
    1327:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);
    1328:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGGetType_C",PCGAMGGetType_GAMG);
    1329:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);
    1330:   pc_gamg->repart           = PETSC_FALSE;
    1331:   pc_gamg->reuse_prol       = PETSC_FALSE;
    1332:   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
    1333:   pc_gamg->min_eq_proc      = 50;
    1334:   pc_gamg->coarse_eq_limit  = 50;
    1335:   pc_gamg->threshold        = 0.;
    1336:   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
    1337:   pc_gamg->emax_id          = -1;
    1338:   pc_gamg->current_level    = 0; /* don't need to init really */
    1339:   pc_gamg->eigtarget[0]     = 0.05;
    1340:   pc_gamg->eigtarget[1]     = 1.05;
    1341:   pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;

    1343:   /* PCSetUp_GAMG assumes that the type has been set, so set it to the default now */
    1344:   PCGAMGSetType(pc,PCGAMGAGG);
    1345:   return(0);
    1346: }

    1350: /*@C
    1351:  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
    1352:     from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
    1353:     when using static libraries.

    1355:  Level: developer

    1357:  .keywords: PC, PCGAMG, initialize, package
    1358:  .seealso: PetscInitialize()
    1359: @*/
    1360: PetscErrorCode PCGAMGInitializePackage(void)
    1361: {

    1365:   if (PCGAMGPackageInitialized) return(0);
    1366:   PCGAMGPackageInitialized = PETSC_TRUE;
    1367:   PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);
    1368:   PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);
    1369:   PetscFunctionListAdd(&GAMGList,PCGAMGCLASSICAL,PCCreateGAMG_Classical);
    1370:   PetscRegisterFinalize(PCGAMGFinalizePackage);

    1372:   /* general events */
    1373:   PetscLogEventRegister("PCGAMGGraph_AGG", 0, &PC_GAMGGraph_AGG);
    1374:   PetscLogEventRegister("PCGAMGGraph_GEO", PC_CLASSID, &PC_GAMGGraph_GEO);
    1375:   PetscLogEventRegister("PCGAMGCoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);
    1376:   PetscLogEventRegister("PCGAMGCoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);
    1377:   PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);
    1378:   PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);
    1379:   PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptProlongator_AGG);

    1381: #if defined PETSC_GAMG_USE_LOG
    1382:   PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);
    1383:   PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);
    1384:   /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
    1385:   /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
    1386:   /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
    1387:   PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);
    1388:   PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);
    1389:   PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);
    1390:   PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);
    1391:   PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);
    1392:   PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);
    1393:   PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);
    1394:   PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);
    1395:   PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);
    1396:   PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);
    1397:   PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);
    1398:   PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);

    1400:   /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
    1401:   /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
    1402:   /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
    1403:   /* create timer stages */
    1404: #if defined GAMG_STAGES
    1405:   {
    1406:     char     str[32];
    1407:     PetscInt lidx;
    1408:     sprintf(str,"MG Level %d (finest)",0);
    1409:     PetscLogStageRegister(str, &gamg_stages[0]);
    1410:     for (lidx=1; lidx<9; lidx++) {
    1411:       sprintf(str,"MG Level %d",lidx);
    1412:       PetscLogStageRegister(str, &gamg_stages[lidx]);
    1413:     }
    1414:   }
    1415: #endif
    1416: #endif
    1417:   return(0);
    1418: }

    1422: /*@C
    1423:  PCGAMGFinalizePackage - This function frees everything from the PCGAMG package. It is
    1424:     called from PetscFinalize() automatically.

    1426:  Level: developer

    1428:  .keywords: Petsc, destroy, package
    1429:  .seealso: PetscFinalize()
    1430: @*/
    1431: PetscErrorCode PCGAMGFinalizePackage(void)
    1432: {

    1436:   PCGAMGPackageInitialized = PETSC_FALSE;
    1437:   PetscFunctionListDestroy(&GAMGList);
    1438:   return(0);
    1439: }

    1443: /*@C
    1444:  PCGAMGRegister - Register a PCGAMG implementation.

    1446:  Input Parameters:
    1447:  + type - string that will be used as the name of the GAMG type.
    1448:  - create - function for creating the gamg context.

    1450:   Level: advanced

    1452:  .seealso: PCGAMGType, PCGAMG, PCGAMGSetType()
    1453: @*/
    1454: PetscErrorCode PCGAMGRegister(PCGAMGType type, PetscErrorCode (*create)(PC))
    1455: {

    1459:   PCGAMGInitializePackage();
    1460:   PetscFunctionListAdd(&GAMGList,type,create);
    1461:   return(0);
    1462: }