Date: 2016-07-24T17:04:51+00:00

Actual source code: gamg.c
petsc-3.7.3 2016-07-24
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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) 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)) { /* 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: #if defined PETSC_GAMG_USE_LOG
    250:         PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);
    251: #endif
    252:         return(0);
    253:       }

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

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

    273:     PetscFree(counts);
    274: #if defined PETSC_GAMG_USE_LOG
    275:     PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);
    276: #endif
    277:     /* 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 */
    278:     {
    279:     Vec            src_crd, dest_crd;
    280:     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
    281:     VecScatter     vecscat;
    282:     PetscScalar    *array;
    283:     IS isscat;

    285:     /* move data (for primal equations only) */
    286:     /* Create a vector to contain the newly ordered element information */
    287:     VecCreate(comm, &dest_crd);
    288:     VecSetSizes(dest_crd, node_data_sz*ncrs_new, PETSC_DECIDE);
    289:     VecSetType(dest_crd,VECSTANDARD); /* this is needed! */
    290:     /*
    291:      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
    292:      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
    293:      */
    294:     PetscMalloc1(ncrs*node_data_sz, &tidx);
    295:     ISGetIndices(is_eq_num_prim, &idx);
    296:     for (ii=0,jj=0; ii<ncrs; ii++) {
    297:       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
    298:       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
    299:     }
    300:     ISRestoreIndices(is_eq_num_prim, &idx);
    301:     ISCreateGeneral(comm, node_data_sz*ncrs, tidx, PETSC_COPY_VALUES, &isscat);
    302:     PetscFree(tidx);
    303:     /*
    304:      Create a vector to contain the original vertex information for each element
    305:      */
    306:     VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs, &src_crd);
    307:     for (jj=0; jj<ndata_cols; jj++) {
    308:       const PetscInt stride0=ncrs*pc_gamg->data_cell_rows;
    309:       for (ii=0; ii<ncrs; ii++) {
    310:         for (kk=0; kk<ndata_rows; kk++) {
    311:           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
    312:           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
    313:           VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);
    314:         }
    315:       }
    316:     }
    317:     VecAssemblyBegin(src_crd);
    318:     VecAssemblyEnd(src_crd);
    319:     /*
    320:       Scatter the element vertex information (still in the original vertex ordering)
    321:       to the correct processor
    322:     */
    323:     VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);
    324:     ISDestroy(&isscat);
    325:     VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);
    326:     VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);
    327:     VecScatterDestroy(&vecscat);
    328:     VecDestroy(&src_crd);
    329:     /*
    330:       Put the element vertex data into a new allocation of the gdata->ele
    331:     */
    332:     PetscFree(pc_gamg->data);
    333:     PetscMalloc1(node_data_sz*ncrs_new, &pc_gamg->data);

    335:     pc_gamg->data_sz = node_data_sz*ncrs_new;
    336:     strideNew        = ncrs_new*ndata_rows;

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

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

    379:       if (!PETSC_TRUE) {
    380:         PetscInt cbs, rbs;
    381:         MatGetBlockSizes(Cmat, &rbs, &cbs);
    382:         PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);
    383:         MatGetBlockSizes(mat, &rbs, &cbs);
    384:         PetscPrintf(MPI_COMM_SELF,"[%d]%s New Mat rbs=%d cbs=%d cr_bs=%d\n",rank,__FUNCT__,rbs,cbs,cr_bs);
    385:       }
    386:     }
    387:     MatDestroy(&Cmat);

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

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

    418:       /* output - repartitioned */
    419:       *a_P_inout = Pnew;
    420:     }
    421:     ISDestroy(&new_eq_indices);

    423:     *a_nactive_proc = new_size; /* output */
    424:   }

    426:   /* outout matrix data */
    427:   if (!PETSC_TRUE) {
    428:     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
    429:     if (!llev) {
    430:       sprintf(fname,"Cmat_%d.m",llev++);
    431:       PetscViewerASCIIOpen(comm,fname,&viewer);
    432:       PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);
    433:       MatView(Amat_fine, viewer);
    434:       PetscViewerPopFormat(viewer);
    435:       PetscViewerDestroy(&viewer);
    436:     }
    437:     sprintf(fname,"Cmat_%d.m",llev++);
    438:     PetscViewerASCIIOpen(comm,fname,&viewer);
    439:     PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);
    440:     MatView(Cmat, viewer);
    441:     PetscViewerPopFormat(viewer);
    442:     PetscViewerDestroy(&viewer);
    443:   }
    444:   return(0);
    445: }

    447: /* -------------------------------------------------------------------------- */
    448: /*
    449:    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
    450:                     by setting data structures and options.

    452:    Input Parameter:
    453: .  pc - the preconditioner context

    455: */
    458: PetscErrorCode PCSetUp_GAMG(PC pc)
    459: {
    461:   PC_MG          *mg      = (PC_MG*)pc->data;
    462:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
    463:   Mat            Pmat     = pc->pmat;
    464:   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
    465:   MPI_Comm       comm;
    466:   PetscMPIInt    rank,size,nactivepe;
    467:   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
    468:   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
    469:   PetscLogDouble nnz0=0.,nnztot=0.;
    470:   MatInfo        info;

    473:   PetscObjectGetComm((PetscObject)pc,&comm);
    474:   MPI_Comm_rank(comm,&rank);
    475:   MPI_Comm_size(comm,&size);

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

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

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

    500:             mglevels[level]->A = B;
    501:           } else {
    502:             KSPGetOperators(mglevels[level]->smoothd,NULL,&B);
    503:             MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);
    504:           }
    505:           KSPSetOperators(mglevels[level]->smoothd,B,B);
    506:           dB   = B;
    507:         }
    508:       }

    510:       PCSetUp_MG(pc);

    512:       return(0);
    513:     }
    514:   }

    516:   if (!pc_gamg->data) {
    517:     if (pc_gamg->orig_data) {
    518:       MatGetBlockSize(Pmat, &bs);
    519:       MatGetLocalSize(Pmat, &qq, NULL);

    521:       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
    522:       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
    523:       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;

    525:       PetscMalloc1(pc_gamg->data_sz, &pc_gamg->data);
    526:       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
    527:     } else {
    528:       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
    529:       pc_gamg->ops->createdefaultdata(pc,Pmat);
    530:     }
    531:   }

    533:   /* cache original data for reuse */
    534:   if (!pc_gamg->orig_data && (PetscBool)(!pc_gamg->reuse_prol)) {
    535:     PetscMalloc1(pc_gamg->data_sz, &pc_gamg->orig_data);
    536:     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
    537:     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
    538:     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
    539:   }

    541:   /* get basic dims */
    542:   MatGetBlockSize(Pmat, &bs);
    543:   MatGetSize(Pmat, &M, &qq);

    545:   MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info); /* global reduction */
    546:   nnz0   = info.nz_used;
    547:   nnztot = info.nz_used;
    548:   PetscInfo6(pc,"level %d) N=%D, n data rows=%d, n data cols=%d, nnz/row (ave)=%d, np=%d\n",
    549:                     0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
    550:                     (int)(nnz0/(PetscReal)M+0.5),size);
    551:

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

    570:       pc_gamg->ops->graph(pc,Aarr[level], &Gmat);
    571:       pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);
    572:       pc_gamg->ops->prolongator(pc,Aarr[level],Gmat,agg_lists,&Prol11);

    574:       /* could have failed to create new level */
    575:       if (Prol11) {
    576:         /* get new block size of coarse matrices */
    577:         MatGetBlockSizes(Prol11, NULL, &bs);

    579:         if (pc_gamg->ops->optprolongator) {
    580:           /* smooth */
    581:           pc_gamg->ops->optprolongator(pc, Aarr[level], &Prol11);
    582:         }

    584:         Parr[level1] = Prol11;
    585:       } else Parr[level1] = NULL;

    587:       if (pc_gamg->use_aggs_in_gasm) {
    588:         PetscInt bs;
    589:         MatGetBlockSizes(Prol11, &bs, NULL);
    590:         PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);
    591:       }

    593:       MatDestroy(&Gmat);
    594:       PetscCDDestroy(agg_lists);
    595:     } /* construct prolongator scope */
    596: #if defined PETSC_GAMG_USE_LOG
    597:     PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);
    598: #endif
    599:     if (!level) Aarr[0] = Pmat; /* use Pmat for finest level setup */
    600:     if (!Parr[level1]) {
    601:        PetscInfo1(pc,"Stop gridding, level %D\n",level);
    602: #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
    603:       PetscLogStagePop();
    604: #endif
    605:       break;
    606:     }
    607: #if defined PETSC_GAMG_USE_LOG
    608:     PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);
    609: #endif

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

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

    618:     MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);
    619:     nnztot += info.nz_used;
    620:     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);

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

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

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

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

    661:       PCMGGetSmoother(pc, lidx, &smoother);
    662:       KSPGetPC(smoother, &subpc);

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

    669:       /* set defaults */
    670:       KSPSetType(smoother, KSPCHEBYSHEV);

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

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

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

    733:     /* clean up */
    734:     for (level=1; level<pc_gamg->Nlevels; level++) {
    735:       MatDestroy(&Parr[level]);
    736:       MatDestroy(&Aarr[level]);
    737:     }

    739:     PCSetUp_MG(pc);
    740:   } else {
    741:     KSP smoother;
    742:     PetscInfo(pc,"One level solver used (system is seen as DD). Using default solver.\n");
    743:     PCMGGetSmoother(pc, 0, &smoother);
    744:     KSPSetOperators(smoother, Aarr[0], Aarr[0]);
    745:     KSPSetType(smoother, KSPPREONLY);
    746:     PCSetUp_MG(pc);
    747:   }
    748:   return(0);
    749: }

    751: /* ------------------------------------------------------------------------- */
    752: /*
    753:  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
    754:    that was created with PCCreate_GAMG().

    756:    Input Parameter:
    757: .  pc - the preconditioner context

    759:    Application Interface Routine: PCDestroy()
    760: */
    763: PetscErrorCode PCDestroy_GAMG(PC pc)
    764: {
    766:   PC_MG          *mg     = (PC_MG*)pc->data;
    767:   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;

    770:   PCReset_GAMG(pc);
    771:   if (pc_gamg->ops->destroy) {
    772:     (*pc_gamg->ops->destroy)(pc);
    773:   }
    774:   PetscRandomDestroy(&pc_gamg->random);
    775:   PetscFree(pc_gamg->ops);
    776:   PetscFree(pc_gamg->gamg_type_name);
    777:   PetscFree(pc_gamg);
    778:   PCDestroy_MG(pc);
    779:   return(0);
    780: }

    785: /*@
    786:    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via processor reduction.

    788:    Logically Collective on PC

    790:    Input Parameters:
    791: +  pc - the preconditioner context
    792: -  n - the number of equations

    795:    Options Database Key:
    796: .  -pc_gamg_process_eq_limit <limit>

    798:    Level: intermediate

    800:    Concepts: Unstructured multigrid preconditioner

    802: .seealso: PCGAMGSetCoarseEqLim()
    803: @*/
    804: PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
    805: {

    810:   PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));
    811:   return(0);
    812: }

    816: static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
    817: {
    818:   PC_MG   *mg      = (PC_MG*)pc->data;
    819:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    822:   if (n>0) pc_gamg->min_eq_proc = n;
    823:   return(0);
    824: }

    828: /*@
    829:    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.

    831:  Collective on PC

    833:    Input Parameters:
    834: +  pc - the preconditioner context
    835: -  n - maximum number of equations to aim for

    837:    Options Database Key:
    838: .  -pc_gamg_coarse_eq_limit <limit>

    840:    Level: intermediate

    842:    Concepts: Unstructured multigrid preconditioner

    844: .seealso: PCGAMGSetProcEqLim()
    845: @*/
    846: PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
    847: {

    852:   PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));
    853:   return(0);
    854: }

    858: static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
    859: {
    860:   PC_MG   *mg      = (PC_MG*)pc->data;
    861:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    864:   if (n>0) pc_gamg->coarse_eq_limit = n;
    865:   return(0);
    866: }

    870: /*@
    871:    PCGAMGSetRepartitioning - Repartition the coarse grids

    873:    Collective on PC

    875:    Input Parameters:
    876: +  pc - the preconditioner context
    877: -  n - PETSC_TRUE or PETSC_FALSE

    879:    Options Database Key:
    880: .  -pc_gamg_repartition <true,false>

    882:    Level: intermediate

    884:    Concepts: Unstructured multigrid preconditioner

    886: .seealso: ()
    887: @*/
    888: PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
    889: {

    894:   PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));
    895:   return(0);
    896: }

    900: static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
    901: {
    902:   PC_MG   *mg      = (PC_MG*)pc->data;
    903:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    906:   pc_gamg->repart = n;
    907:   return(0);
    908: }

    912: /*@
    913:    PCGAMGSetReuseInterpolation - Reuse prolongation when rebuilding preconditioner

    915:    Collective on PC

    917:    Input Parameters:
    918: +  pc - the preconditioner context
    919: -  n - PETSC_TRUE or PETSC_FALSE

    921:    Options Database Key:
    922: .  -pc_gamg_reuse_interpolation <true,false>

    924:    Level: intermediate

    926:    Concepts: Unstructured multigrid preconditioner

    928: .seealso: ()
    929: @*/
    930: PetscErrorCode PCGAMGSetReuseInterpolation(PC pc, PetscBool n)
    931: {

    936:   PetscTryMethod(pc,"PCGAMGSetReuseInterpolation_C",(PC,PetscBool),(pc,n));
    937:   return(0);
    938: }

    942: static PetscErrorCode PCGAMGSetReuseInterpolation_GAMG(PC pc, PetscBool n)
    943: {
    944:   PC_MG   *mg      = (PC_MG*)pc->data;
    945:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    948:   pc_gamg->reuse_prol = n;
    949:   return(0);
    950: }

    954: /*@
    955:    PCGAMGSetUseASMAggs -

    957:    Collective on PC

    959:    Input Parameters:
    960: .  pc - the preconditioner context

    963:    Options Database Key:
    964: .  -pc_gamg_use_agg_gasm

    966:    Level: intermediate

    968:    Concepts: Unstructured multigrid preconditioner

    970: .seealso: ()
    971: @*/
    972: PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
    973: {

    978:   PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));
    979:   return(0);
    980: }

    984: static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
    985: {
    986:   PC_MG   *mg      = (PC_MG*)pc->data;
    987:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    990:   pc_gamg->use_aggs_in_gasm = n;
    991:   return(0);
    992: }

    996: /*@
    997:    PCGAMGSetNlevels -  Sets the maximum number of levels PCGAMG will use

    999:    Not collective on PC

    1001:    Input Parameters:
    1002: +  pc - the preconditioner
    1003: -  n - the maximum number of levels to use

    1005:    Options Database Key:
    1006: .  -pc_mg_levels

    1008:    Level: intermediate

    1010:    Concepts: Unstructured multigrid preconditioner

    1012: .seealso: ()
    1013: @*/
    1014: PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
    1015: {

    1020:   PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));
    1021:   return(0);
    1022: }

    1026: static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
    1027: {
    1028:   PC_MG   *mg      = (PC_MG*)pc->data;
    1029:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    1032:   pc_gamg->Nlevels = n;
    1033:   return(0);
    1034: }

    1038: /*@
    1039:    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph

    1041:    Not collective on PC

    1043:    Input Parameters:
    1044: +  pc - the preconditioner context
    1045: -  threshold - the threshold value, 0.0 means keep all nonzero entries in the graph; negative means keep even zero entries in the graph

    1047:    Options Database Key:
    1048: .  -pc_gamg_threshold <threshold>

    1050:    Level: intermediate

    1052:    Concepts: Unstructured multigrid preconditioner

    1054: .seealso: ()
    1055: @*/
    1056: PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
    1057: {

    1062:   PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));
    1063:   return(0);
    1064: }

    1068: static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
    1069: {
    1070:   PC_MG   *mg      = (PC_MG*)pc->data;
    1071:   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;

    1074:   pc_gamg->threshold = n;
    1075:   return(0);
    1076: }

    1080: /*@
    1081:    PCGAMGSetType - Set solution method

    1083:    Collective on PC

    1085:    Input Parameters:
    1086: +  pc - the preconditioner context
    1087: -  type - PCGAMGAGG, PCGAMGGEO, or PCGAMGCLASSICAL

    1089:    Options Database Key:
    1090: .  -pc_gamg_type <agg,geo,classical>

    1092:    Level: intermediate

    1094:    Concepts: Unstructured multigrid preconditioner

    1096: .seealso: PCGAMGGetType(), PCGAMG
    1097: @*/
    1098: PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
    1099: {

    1104:   PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));
    1105:   return(0);
    1106: }

    1110: /*@
    1111:    PCGAMGGetType - Get solution method

    1113:    Collective on PC

    1115:    Input Parameter:
    1116: .  pc - the preconditioner context

    1118:    Output Parameter:
    1119: .  type - the type of algorithm used

    1121:    Level: intermediate

    1123:    Concepts: Unstructured multigrid preconditioner

    1125: .seealso: PCGAMGSetType(), PCGAMGType
    1126: @*/
    1127: PetscErrorCode PCGAMGGetType(PC pc, PCGAMGType *type)
    1128: {

    1133:   PetscUseMethod(pc,"PCGAMGGetType_C",(PC,PCGAMGType*),(pc,type));
    1134:   return(0);
    1135: }

    1139: static PetscErrorCode PCGAMGGetType_GAMG(PC pc, PCGAMGType *type)
    1140: {
    1141:   PC_MG          *mg      = (PC_MG*)pc->data;
    1142:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1145:   *type = pc_gamg->type;
    1146:   return(0);
    1147: }

    1151: static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
    1152: {
    1153:   PetscErrorCode ierr,(*r)(PC);
    1154:   PC_MG          *mg      = (PC_MG*)pc->data;
    1155:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1158:   pc_gamg->type = type;
    1159:   PetscFunctionListFind(GAMGList,type,&r);
    1160:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
    1161:   if (pc_gamg->ops->destroy) {
    1162:     (*pc_gamg->ops->destroy)(pc);
    1163:     PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));
    1164:     pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
    1165:     /* cleaning up common data in pc_gamg - this should disapear someday */
    1166:     pc_gamg->data_cell_cols = 0;
    1167:     pc_gamg->data_cell_rows = 0;
    1168:     pc_gamg->orig_data_cell_cols = 0;
    1169:     pc_gamg->orig_data_cell_rows = 0;
    1170:     PetscFree(pc_gamg->data);
    1171:     pc_gamg->data_sz = 0;
    1172:   }
    1173:   PetscFree(pc_gamg->gamg_type_name);
    1174:   PetscStrallocpy(type,&pc_gamg->gamg_type_name);
    1175:   (*r)(pc);
    1176:   return(0);
    1177: }

    1181: static PetscErrorCode PCView_GAMG(PC pc,PetscViewer viewer)
    1182: {
    1184:   PC_MG          *mg      = (PC_MG*)pc->data;
    1185:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;

    1188:   PetscViewerASCIIPrintf(viewer,"    GAMG specific options\n");
    1189:   PetscViewerASCIIPrintf(viewer,"      Threshold for dropping small values from graph %g\n",(double)pc_gamg->threshold);
    1190:   if (pc_gamg->ops->view) {
    1191:     (*pc_gamg->ops->view)(pc,viewer);
    1192:   }
    1193:   return(0);
    1194: }

    1198: PetscErrorCode PCSetFromOptions_GAMG(PetscOptionItems *PetscOptionsObject,PC pc)
    1199: {
    1201:   PC_MG          *mg      = (PC_MG*)pc->data;
    1202:   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
    1203:   PetscBool      flag;
    1204:   MPI_Comm       comm;
    1205:   char           prefix[256];
    1206:   const char     *pcpre;

    1209:   PetscObjectGetComm((PetscObject)pc,&comm);
    1210:   PetscOptionsHead(PetscOptionsObject,"GAMG options");
    1211:   {
    1212:     char tname[256];
    1213:     PetscOptionsFList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, pc_gamg->gamg_type_name, tname, sizeof(tname), &flag);
    1214:     if (flag) {
    1215:       PCGAMGSetType(pc,tname);
    1216:     }
    1217:     PetscOptionsBool("-pc_gamg_repartition","Repartion coarse grids","PCGAMGRepartitioning",pc_gamg->repart,&pc_gamg->repart,NULL);
    1218:     PetscOptionsBool("-pc_gamg_reuse_interpolation","Reuse prolongation operator","PCGAMGReuseInterpolation",pc_gamg->reuse_prol,&pc_gamg->reuse_prol,NULL);
    1219:     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);
    1220:     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);
    1221:     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);
    1222:     PetscOptionsReal("-pc_gamg_threshold","Relative threshold to use for dropping edges in aggregation graph","PCGAMGSetThreshold",pc_gamg->threshold,&pc_gamg->threshold,&flag);
    1223:     PetscOptionsInt("-pc_mg_levels","Set number of MG levels","PCGAMGSetNlevels",pc_gamg->Nlevels,&pc_gamg->Nlevels,NULL);

    1225:     /* set options for subtype */
    1226:     if (pc_gamg->ops->setfromoptions) {(*pc_gamg->ops->setfromoptions)(PetscOptionsObject,pc);}
    1227:   }
    1228:   PCGetOptionsPrefix(pc, &pcpre);
    1229:   PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");
    1230:   PetscObjectSetOptionsPrefix((PetscObject)pc_gamg->random,prefix);
    1231:   PetscRandomSetFromOptions(pc_gamg->random);
    1232:   PetscOptionsTail();
    1233:   return(0);
    1234: }

    1236: /* -------------------------------------------------------------------------- */
    1237: /*MC
    1238:      PCGAMG - Geometric algebraic multigrid (AMG) preconditioner

    1240:    Options Database Keys:
    1241:    Multigrid options(inherited)
    1242: +  -pc_mg_cycles <v>: v or w (PCMGSetCycleType())
    1243: .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
    1244: .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
    1245: -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade

    1248:   Notes: In order to obtain good performance for PCGAMG for vector valued problems you must
    1249: $       Call MatSetBlockSize() to indicate the number of degrees of freedom per grid point
    1250: $       Call MatSetNearNullSpace() (or PCSetCoordinates() if solving the equations of elasticity) to indicate the near null space of the operator
    1251: $       See the Users Manual Chapter 4 for more details

    1253:   Level: intermediate

    1255:   Concepts: algebraic multigrid

    1257: .seealso:  PCCreate(), PCSetType(), MatSetBlockSize(), PCMGType, PCSetCoordinates(), MatSetNearNullSpace(), PCGAMGSetType(), PCGAMGAGG, PCGAMGGEO, PCGAMGCLASSICAL, PCGAMGSetProcEqLim(),
    1258:            PCGAMGSetCoarseEqLim(), PCGAMGSetRepartitioning(), PCGAMGRegister(), PCGAMGSetReuseInterpolation(), PCGAMGSetUseASMAggs(), PCGAMGSetNlevels(), PCGAMGSetThreshold(), PCGAMGGetType()
    1259: M*/

    1263: PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
    1264: {
    1266:   PC_GAMG        *pc_gamg;
    1267:   PC_MG          *mg;

    1270:   /* register AMG type */
    1271:   PCGAMGInitializePackage();

    1273:   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
    1274:   PCSetType(pc, PCMG);
    1275:   PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);

    1277:   /* create a supporting struct and attach it to pc */
    1278:   PetscNewLog(pc,&pc_gamg);
    1279:   mg           = (PC_MG*)pc->data;
    1280:   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally from PCMG by GAMG code */
    1281:   mg->innerctx = pc_gamg;

    1283:   PetscNewLog(pc,&pc_gamg->ops);

    1285:   pc_gamg->setup_count = 0;
    1286:   /* these should be in subctx but repartitioning needs simple arrays */
    1287:   pc_gamg->data_sz = 0;
    1288:   pc_gamg->data    = 0;

    1290:   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
    1291:   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
    1292:   pc->ops->setup          = PCSetUp_GAMG;
    1293:   pc->ops->reset          = PCReset_GAMG;
    1294:   pc->ops->destroy        = PCDestroy_GAMG;
    1295:   mg->view                = PCView_GAMG;

    1297:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);
    1298:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);
    1299:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);
    1300:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseInterpolation_C",PCGAMGSetReuseInterpolation_GAMG);
    1301:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);
    1302:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);
    1303:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);
    1304:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGGetType_C",PCGAMGGetType_GAMG);
    1305:   PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);
    1306:   pc_gamg->repart           = PETSC_FALSE;
    1307:   pc_gamg->reuse_prol       = PETSC_FALSE;
    1308:   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
    1309:   pc_gamg->min_eq_proc      = 50;
    1310:   pc_gamg->coarse_eq_limit  = 50;
    1311:   pc_gamg->threshold        = 0.;
    1312:   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
    1313:   pc_gamg->current_level    = 0; /* don't need to init really */
    1314:   pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;

    1316:   PetscRandomCreate(PetscObjectComm((PetscObject)pc),&pc_gamg->random);

    1318:   /* PCSetUp_GAMG assumes that the type has been set, so set it to the default now */
    1319:   PCGAMGSetType(pc,PCGAMGAGG);
    1320:   return(0);
    1321: }

    1325: /*@C
    1326:  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
    1327:     from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
    1328:     when using static libraries.

    1330:  Level: developer

    1332:  .keywords: PC, PCGAMG, initialize, package
    1333:  .seealso: PetscInitialize()
    1334: @*/
    1335: PetscErrorCode PCGAMGInitializePackage(void)
    1336: {

    1340:   if (PCGAMGPackageInitialized) return(0);
    1341:   PCGAMGPackageInitialized = PETSC_TRUE;
    1342:   PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);
    1343:   PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);
    1344:   PetscFunctionListAdd(&GAMGList,PCGAMGCLASSICAL,PCCreateGAMG_Classical);
    1345:   PetscRegisterFinalize(PCGAMGFinalizePackage);

    1347:   /* general events */
    1348:   PetscLogEventRegister("PCGAMGGraph_AGG", 0, &PC_GAMGGraph_AGG);
    1349:   PetscLogEventRegister("PCGAMGGraph_GEO", PC_CLASSID, &PC_GAMGGraph_GEO);
    1350:   PetscLogEventRegister("PCGAMGCoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);
    1351:   PetscLogEventRegister("PCGAMGCoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);
    1352:   PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);
    1353:   PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);
    1354:   PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptProlongator_AGG);

    1356: #if defined PETSC_GAMG_USE_LOG
    1357:   PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);
    1358:   PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);
    1359:   /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
    1360:   /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
    1361:   /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
    1362:   PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);
    1363:   PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);
    1364:   PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);
    1365:   PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);
    1366:   PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);
    1367:   PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);
    1368:   PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);
    1369:   PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);
    1370:   PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);
    1371:   PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);
    1372:   PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);
    1373:   PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);

    1375:   /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
    1376:   /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
    1377:   /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
    1378:   /* create timer stages */
    1379: #if defined GAMG_STAGES
    1380:   {
    1381:     char     str[32];
    1382:     PetscInt lidx;
    1383:     sprintf(str,"MG Level %d (finest)",0);
    1384:     PetscLogStageRegister(str, &gamg_stages[0]);
    1385:     for (lidx=1; lidx<9; lidx++) {
    1386:       sprintf(str,"MG Level %d",lidx);
    1387:       PetscLogStageRegister(str, &gamg_stages[lidx]);
    1388:     }
    1389:   }
    1390: #endif
    1391: #endif
    1392:   return(0);
    1393: }

    1397: /*@C
    1398:  PCGAMGFinalizePackage - This function frees everything from the PCGAMG package. It is
    1399:     called from PetscFinalize() automatically.

    1401:  Level: developer

    1403:  .keywords: Petsc, destroy, package
    1404:  .seealso: PetscFinalize()
    1405: @*/
    1406: PetscErrorCode PCGAMGFinalizePackage(void)
    1407: {

    1411:   PCGAMGPackageInitialized = PETSC_FALSE;
    1412:   PetscFunctionListDestroy(&GAMGList);
    1413:   return(0);
    1414: }

    1418: /*@C
    1419:  PCGAMGRegister - Register a PCGAMG implementation.

    1421:  Input Parameters:
    1422:  + type - string that will be used as the name of the GAMG type.
    1423:  - create - function for creating the gamg context.

    1425:   Level: advanced

    1427:  .seealso: PCGAMGType, PCGAMG, PCGAMGSetType()
    1428: @*/
    1429: PetscErrorCode PCGAMGRegister(PCGAMGType type, PetscErrorCode (*create)(PC))
    1430: {

    1434:   PCGAMGInitializePackage();
    1435:   PetscFunctionListAdd(&GAMGList,type,create);
    1436:   return(0);
    1437: }