xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision bebe2cf65d55febe21a5af8db2bd2e168caaa2e7)
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 */
8 
9 #if defined PETSC_GAMG_USE_LOG
10 PetscLogEvent petsc_gamg_setup_events[NUM_SET];
11 #endif
12 
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
22 
23 #define GAMG_MAXLEVELS 30
24 
25 /* #define GAMG_STAGES */
26 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
27 static PetscLogStage gamg_stages[GAMG_MAXLEVELS];
28 #endif
29 
30 static PetscFunctionList GAMGList = 0;
31 static PetscBool PCGAMGPackageInitialized;
32 
33 /* ----------------------------------------------------------------------------- */
34 #undef __FUNCT__
35 #define __FUNCT__ "PCReset_GAMG"
36 PetscErrorCode PCReset_GAMG(PC pc)
37 {
38   PetscErrorCode ierr;
39   PC_MG          *mg      = (PC_MG*)pc->data;
40   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
41 
42   PetscFunctionBegin;
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     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
46   }
47   pc_gamg->data_sz = 0;
48   ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
49   PetscFunctionReturn(0);
50 }
51 
52 /* -------------------------------------------------------------------------- */
53 /*
54    PCGAMGCreateLevel_GAMG: create coarse op with RAP.  repartition and/or reduce number
55      of active processors.
56 
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 */
68 
69 #undef __FUNCT__
70 #define __FUNCT__ "PCGAMGCreateLevel_GAMG"
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;
82 
83   PetscFunctionBegin;
84   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
85   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
86   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
87   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
88   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
89 
90   /* set 'ncrs' (nodes), 'ncrs_eq' (equations)*/
91   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
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     ierr = MatGetBlockSize(Cmat, &bs);CHKERRQ(ierr);
97     ncrs = ncrs_eq/bs;
98   }
99 
100   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
101   {
102     PetscInt ncrs_eq_glob;
103     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
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   }
108 
109   if (Pcolumnperm) *Pcolumnperm = NULL;
110 
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;
115 
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     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
120 #endif
121     /* make 'is_eq_newproc' */
122     ierr = PetscMalloc1(size, &counts);CHKERRQ(ierr);
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;
126 
127      ierr = PetscInfo3(pc,"Repartition: size (active): %D --> %D, neq = %D\n",*a_nactive_proc,new_size,ncrs_eq);CHKERRQ(ierr);
128 
129       /* get 'adj' */
130       if (cr_bs == 1) {
131         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
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;
141 
142         ierr = PetscMalloc2(ncrs, &d_nnz,ncrs, &o_nnz);CHKERRQ(ierr);
143         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
144         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
145         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
146           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
147           d_nnz[jj] = ncols/cr_bs;
148           o_nnz[jj] = ncols/cr_bs;
149           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
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         }
153 
154         ierr = MatGetType(Amat_fine,&mtype);CHKERRQ(ierr);
155         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
156         ierr = MatSetSizes(tMat, ncrs, ncrs,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
157         ierr = MatSetType(tMat,mtype);CHKERRQ(ierr);
158         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
159         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
160         ierr = PetscFree2(d_nnz,o_nnz);CHKERRQ(ierr);
161 
162         for (ii = Istart_crs; ii < Iend_crs; ii++) {
163           PetscInt dest_row = ii/cr_bs;
164           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
165           for (jj = 0; jj < ncols; jj++) {
166             PetscInt    dest_col = idx[jj]/cr_bs;
167             PetscScalar v        = 1.0;
168             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
169           }
170           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
171         }
172         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
173         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
174 
175         if (llev++ == -1) {
176           PetscViewer viewer; char fname[32];
177           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
178           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
179           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
180           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
181         }
182 
183         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
184 
185         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
186       } /* create 'adj' */
187 
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;
195 
196         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
197         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
198         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
199         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
200         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
201         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
202         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
203         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
204         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
205 
206         /* collect IS info */
207         ierr     = PetscMalloc1(ncrs_eq, &newproc_idx);CHKERRQ(ierr);
208         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
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         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
217         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
218       }
219       ierr = MatDestroy(&adj);CHKERRQ(ierr);
220 
221       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
222       ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
223     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
224 
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;
244 
245       if (new_size==nactive) {
246         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
247         ierr        = PetscFree(counts);CHKERRQ(ierr);
248         ierr = PetscInfo2(pc,"Aggregate processors noop: new_size=%D, neq(loc)=%D\n",new_size,ncrs_eq);CHKERRQ(ierr);
249         PetscFunctionReturn(0);
250       }
251 
252       ierr = PetscInfo1(pc,"Number of equations (loc) %D with simple aggregation\n",ncrs_eq);CHKERRQ(ierr);
253       targetPE = rank/rfactor;
254       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
255     } /* end simple 'is_eq_newproc' */
256 
257     /*
258      Create an index set from the is_eq_newproc index set to indicate the mapping TO
259      */
260     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
261     is_eq_num_prim = is_eq_num;
262     /*
263       Determine how many equations/vertices are assigned to each processor
264      */
265     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
266     ncrs_eq_new = counts[rank];
267     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
268     ncrs_new = ncrs_eq_new/cr_bs; /* eqs */
269 
270     ierr = PetscFree(counts);CHKERRQ(ierr);
271 #if defined PETSC_GAMG_USE_LOG
272     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
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;
281 
282     /* move data (for primal equations only) */
283     /* Create a vector to contain the newly ordered element information */
284     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
285     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_new, PETSC_DECIDE);CHKERRQ(ierr);
286     ierr = VecSetType(dest_crd,VECSTANDARD);CHKERRQ(ierr); /* 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     ierr = PetscMalloc1(ncrs*node_data_sz, &tidx);CHKERRQ(ierr);
292     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
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     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
298     ierr = ISCreateGeneral(comm, node_data_sz*ncrs, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
299     ierr = PetscFree(tidx);CHKERRQ(ierr);
300     /*
301      Create a vector to contain the original vertex information for each element
302      */
303     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs, &src_crd);CHKERRQ(ierr);
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           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
311         }
312       }
313     }
314     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
315     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
316     /*
317       Scatter the element vertex information (still in the original vertex ordering)
318       to the correct processor
319     */
320     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
321     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
322     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
323     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
324     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
325     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
326     /*
327       Put the element vertex data into a new allocation of the gdata->ele
328     */
329     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
330     ierr = PetscMalloc1(node_data_sz*ncrs_new, &pc_gamg->data);CHKERRQ(ierr);
331 
332     pc_gamg->data_sz = node_data_sz*ncrs_new;
333     strideNew        = ncrs_new*ndata_rows;
334 
335     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
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     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
345     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
346     }
347     /* move A and P (columns) with new layout */
348 #if defined PETSC_GAMG_USE_LOG
349     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
350 #endif
351 
352     /*
353       Invert for MatGetSubMatrix
354     */
355     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
356     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
357     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
358     if (is_eq_num != is_eq_num_prim) {
359       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
360     }
361     if (Pcolumnperm) {
362       ierr = PetscObjectReference((PetscObject)new_eq_indices);CHKERRQ(ierr);
363       *Pcolumnperm = new_eq_indices;
364     }
365     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
366 #if defined PETSC_GAMG_USE_LOG
367     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
368     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
369 #endif
370     /* 'a_Amat_crs' output */
371     {
372       Mat mat;
373       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
374       *a_Amat_crs = mat;
375 
376       if (!PETSC_TRUE) {
377         PetscInt cbs, rbs;
378         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
379         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
380         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
381         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s New Mat rbs=%d cbs=%d cr_bs=%d\n",rank,__FUNCT__,rbs,cbs,cr_bs);CHKERRQ(ierr);
382       }
383     }
384     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
385 
386 #if defined PETSC_GAMG_USE_LOG
387     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
388 #endif
389     /* prolongator */
390     {
391       IS       findices;
392       PetscInt Istart,Iend;
393       Mat      Pnew;
394       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
395 #if defined PETSC_GAMG_USE_LOG
396       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
397 #endif
398       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
399       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
400       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
401       ierr = ISDestroy(&findices);CHKERRQ(ierr);
402 
403       if (!PETSC_TRUE) {
404         PetscInt cbs, rbs;
405         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
406         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
407         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
408         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
409       }
410 #if defined PETSC_GAMG_USE_LOG
411       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
412 #endif
413       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
414 
415       /* output - repartitioned */
416       *a_P_inout = Pnew;
417     }
418     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
419 
420     *a_nactive_proc = new_size; /* output */
421   }
422 
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       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
430       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
431       ierr = PetscViewerDestroy(&viewer);
432     }
433     sprintf(fname,"Cmat_%d.m",llev++);
434     PetscViewerASCIIOpen(comm,fname,&viewer);
435     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
436     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
437     ierr = PetscViewerDestroy(&viewer);
438   }
439   PetscFunctionReturn(0);
440 }
441 
442 /* -------------------------------------------------------------------------- */
443 /*
444    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
445                     by setting data structures and options.
446 
447    Input Parameter:
448 .  pc - the preconditioner context
449 
450 */
451 #undef __FUNCT__
452 #define __FUNCT__ "PCSetUp_GAMG"
453 PetscErrorCode PCSetUp_GAMG(PC pc)
454 {
455   PetscErrorCode ierr;
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;
467 
468   PetscFunctionBegin;
469   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
470   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
471   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
472 
473   if (pc_gamg->setup_count++ > 0) {
474     if ((PetscBool)(!pc_gamg->reuse_prol)) {
475       /* reset everything */
476       ierr = PCReset_MG(pc);CHKERRQ(ierr);
477       pc->setupcalled = 0;
478     } else {
479       PC_MG_Levels **mglevels = mg->levels;
480       /* just do Galerkin grids */
481       Mat          B,dA,dB;
482 
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         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB);CHKERRQ(ierr);
487         /* (re)set to get dirty flag */
488         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB);CHKERRQ(ierr);
489 
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             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
494             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
495 
496             mglevels[level]->A = B;
497           } else {
498             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B);CHKERRQ(ierr);
499             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
500           }
501           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B);CHKERRQ(ierr);
502           dB   = B;
503         }
504       }
505 
506       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
507 
508       PetscFunctionReturn(0);
509     }
510   }
511 
512   if (!pc_gamg->data) {
513     if (pc_gamg->orig_data) {
514       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
515       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
516 
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;
520 
521       ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->data);CHKERRQ(ierr);
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       ierr = pc_gamg->ops->createdefaultdata(pc,Pmat);CHKERRQ(ierr);
526     }
527   }
528 
529   /* cache original data for reuse */
530   if (!pc_gamg->orig_data && (PetscBool)(!pc_gamg->reuse_prol)) {
531     ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->orig_data);CHKERRQ(ierr);
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   }
536 
537   /* get basic dims */
538   ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
539   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
540 
541   ierr = MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr); /* global reduction */
542   nnz0   = info.nz_used;
543   nnztot = info.nz_used;
544   ierr = 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   CHKERRQ(ierr);
548 
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     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
557 #if (defined GAMG_STAGES)
558     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
559 #endif
560 #endif
561     { /* construct prolongator */
562       Mat              Gmat;
563       PetscCoarsenData *agg_lists;
564       Mat              Prol11;
565 
566       ierr = pc_gamg->ops->graph(pc,Aarr[level], &Gmat);CHKERRQ(ierr);
567       ierr = pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
568       ierr = pc_gamg->ops->prolongator(pc,Aarr[level],Gmat,agg_lists,&Prol11);CHKERRQ(ierr);
569 
570       /* could have failed to create new level */
571       if (Prol11) {
572         /* get new block size of coarse matrices */
573         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
574 
575         if (pc_gamg->ops->optprolongator) {
576           /* smooth */
577           ierr = pc_gamg->ops->optprolongator(pc, Aarr[level], &Prol11);CHKERRQ(ierr);
578         }
579 
580         Parr[level1] = Prol11;
581       } else Parr[level1] = NULL;
582 
583       if (pc_gamg->use_aggs_in_gasm) {
584         PetscInt bs;
585         ierr = MatGetBlockSizes(Prol11, &bs, NULL);CHKERRQ(ierr);
586         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
587       }
588 
589       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
590       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
591     } /* construct prolongator scope */
592 #if defined PETSC_GAMG_USE_LOG
593     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
594 #endif
595     /* cache eigen estimate */
596     if (pc_gamg->emax_id != -1) {
597       PetscBool flag;
598       ierr = PetscObjectComposedDataGetReal((PetscObject)Aarr[level], pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
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       ierr =  PetscInfo1(pc,"Stop gridding, level %D\n",level);CHKERRQ(ierr);
604 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
605       ierr = PetscLogStagePop();CHKERRQ(ierr);
606 #endif
607       break;
608     }
609 #if defined PETSC_GAMG_USE_LOG
610     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
611 #endif
612 
613     ierr = pc_gamg->ops->createlevel(pc, Aarr[level], bs,&Parr[level1], &Aarr[level1], &nactivepe, NULL);CHKERRQ(ierr);
614 
615 #if defined PETSC_GAMG_USE_LOG
616     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
617 #endif
618     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
619 
620     ierr = MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
621     nnztot += info.nz_used;
622     ierr = 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);CHKERRQ(ierr);
623 
624 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
625     ierr = PetscLogStagePop();CHKERRQ(ierr);
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       ierr =  PetscInfo2(pc,"HARD stop of coarsening on level %D.  Grid too small: %D block nodes\n",level,M/bs);CHKERRQ(ierr);
630       level++;
631       break;
632     }
633   } /* levels */
634   ierr                  = PetscFree(pc_gamg->data);CHKERRQ(ierr);
635 
636   ierr = PetscInfo2(pc,"%D levels, grid complexity = %g\n",level+1,nnztot/nnz0);CHKERRQ(ierr);
637   pc_gamg->Nlevels = level + 1;
638   fine_level       = level;
639   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
640 
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       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
648       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level]);CHKERRQ(ierr);
649       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
650       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
651     }
652     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0]);CHKERRQ(ierr);
653 
654     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
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;
662 
663       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
664       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
665 
666       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
667       /* set ops */
668       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level]);CHKERRQ(ierr);
669       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
670 
671       /* set defaults */
672       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
673 
674       /* set blocks for GASM smoother that uses the 'aggregates' */
675       if (pc_gamg->use_aggs_in_gasm) {
676         PetscInt sz;
677         IS       *is;
678 
679         sz   = nASMBlocksArr[level];
680         is   = ASMLocalIDsArr[level];
681         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
682         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
683         if (sz==0) {
684           IS       is;
685           PetscInt my0,kk;
686           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
687           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
688           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
689           ierr = ISDestroy(&is);CHKERRQ(ierr);
690         } else {
691           PetscInt kk;
692           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
693           for (kk=0; kk<sz; kk++) {
694             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
695           }
696           ierr = PetscFree(is);CHKERRQ(ierr);
697         }
698         ASMLocalIDsArr[level] = NULL;
699         nASMBlocksArr[level]  = 0;
700         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
701       } else {
702         ierr = PCSetType(subpc, PCSOR);CHKERRQ(ierr);
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       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
710       ierr = KSPSetOperators(smoother, Lmat, Lmat);CHKERRQ(ierr);
711       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
712       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
713       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
714       ierr = PCSetUp(subpc);CHKERRQ(ierr);
715       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
716       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
717       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
718       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
719       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
720       ierr = KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);CHKERRQ(ierr);
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     }
726 
727     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
728     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
729     ierr = PCSetFromOptions_MG(PetscOptionsObject,pc);CHKERRQ(ierr);
730     ierr = PetscOptionsEnd();CHKERRQ(ierr);
731     if (!mg->galerkin) SETERRQ(comm,PETSC_ERR_USER,"PCGAMG must use Galerkin for coarse operators.");
732     if (mg->galerkin == 1) mg->galerkin = 2;
733 
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;
739 
740       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
741       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
742 
743       /* do my own cheby */
744       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
745       if (0 && flag) {
746         PetscReal emax, emin;
747         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
748         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCSOR, &flag2);CHKERRQ(ierr);
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           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
754           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
755           emin  = emax * pc_gamg->eigtarget[0];
756           emax *= pc_gamg->eigtarget[1];
757           ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
758         }
759       } /* setup checby flag */
760     } /* non-coarse levels */
761 
762     /* clean up */
763     for (level=1; level<pc_gamg->Nlevels; level++) {
764       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
765       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
766     }
767 
768     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
769   } else {
770     KSP smoother;
771     ierr = PetscInfo(pc,"One level solver used (system is seen as DD). Using default solver.\n");CHKERRQ(ierr);
772     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
773     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0]);CHKERRQ(ierr);
774     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
775     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
776   }
777   PetscFunctionReturn(0);
778 }
779 
780 /* ------------------------------------------------------------------------- */
781 /*
782  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
783    that was created with PCCreate_GAMG().
784 
785    Input Parameter:
786 .  pc - the preconditioner context
787 
788    Application Interface Routine: PCDestroy()
789 */
790 #undef __FUNCT__
791 #define __FUNCT__ "PCDestroy_GAMG"
792 PetscErrorCode PCDestroy_GAMG(PC pc)
793 {
794   PetscErrorCode ierr;
795   PC_MG          *mg     = (PC_MG*)pc->data;
796   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
797 
798   PetscFunctionBegin;
799   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
800   if (pc_gamg->ops->destroy) {
801     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
802   }
803   ierr = PetscFree(pc_gamg->ops);CHKERRQ(ierr);
804   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
805   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
806   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
807   PetscFunctionReturn(0);
808 }
809 
810 
811 #undef __FUNCT__
812 #define __FUNCT__ "PCGAMGSetProcEqLim"
813 /*@
814    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via processor reduction.
815 
816    Logically Collective on PC
817 
818    Input Parameters:
819 +  pc - the preconditioner context
820 -  n - the number of equations
821 
822 
823    Options Database Key:
824 .  -pc_gamg_process_eq_limit <limit>
825 
826    Level: intermediate
827 
828    Concepts: Unstructured multigrid preconditioner
829 
830 .seealso: PCGAMGSetCoarseEqLim()
831 @*/
832 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
833 {
834   PetscErrorCode ierr;
835 
836   PetscFunctionBegin;
837   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
838   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
839   PetscFunctionReturn(0);
840 }
841 
842 #undef __FUNCT__
843 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
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;
848 
849   PetscFunctionBegin;
850   if (n>0) pc_gamg->min_eq_proc = n;
851   PetscFunctionReturn(0);
852 }
853 
854 #undef __FUNCT__
855 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
856 /*@
857    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
858 
859  Collective on PC
860 
861    Input Parameters:
862 +  pc - the preconditioner context
863 -  n - maximum number of equations to aim for
864 
865    Options Database Key:
866 .  -pc_gamg_coarse_eq_limit <limit>
867 
868    Level: intermediate
869 
870    Concepts: Unstructured multigrid preconditioner
871 
872 .seealso: PCGAMGSetProcEqLim()
873 @*/
874 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
875 {
876   PetscErrorCode ierr;
877 
878   PetscFunctionBegin;
879   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
880   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
881   PetscFunctionReturn(0);
882 }
883 
884 #undef __FUNCT__
885 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
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;
890 
891   PetscFunctionBegin;
892   if (n>0) pc_gamg->coarse_eq_limit = n;
893   PetscFunctionReturn(0);
894 }
895 
896 #undef __FUNCT__
897 #define __FUNCT__ "PCGAMGSetRepartitioning"
898 /*@
899    PCGAMGSetRepartitioning - Repartition the coarse grids
900 
901    Collective on PC
902 
903    Input Parameters:
904 +  pc - the preconditioner context
905 -  n - PETSC_TRUE or PETSC_FALSE
906 
907    Options Database Key:
908 .  -pc_gamg_repartition <true,false>
909 
910    Level: intermediate
911 
912    Concepts: Unstructured multigrid preconditioner
913 
914 .seealso: ()
915 @*/
916 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
917 {
918   PetscErrorCode ierr;
919 
920   PetscFunctionBegin;
921   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
922   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
923   PetscFunctionReturn(0);
924 }
925 
926 #undef __FUNCT__
927 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
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;
932 
933   PetscFunctionBegin;
934   pc_gamg->repart = n;
935   PetscFunctionReturn(0);
936 }
937 
938 #undef __FUNCT__
939 #define __FUNCT__ "PCGAMGSetReuseInterpolation"
940 /*@
941    PCGAMGSetReuseInterpolation - Reuse prolongation when rebuilding preconditioner
942 
943    Collective on PC
944 
945    Input Parameters:
946 +  pc - the preconditioner context
947 -  n - PETSC_TRUE or PETSC_FALSE
948 
949    Options Database Key:
950 .  -pc_gamg_reuse_interpolation <true,false>
951 
952    Level: intermediate
953 
954    Concepts: Unstructured multigrid preconditioner
955 
956 .seealso: ()
957 @*/
958 PetscErrorCode PCGAMGSetReuseInterpolation(PC pc, PetscBool n)
959 {
960   PetscErrorCode ierr;
961 
962   PetscFunctionBegin;
963   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
964   ierr = PetscTryMethod(pc,"PCGAMGSetReuseInterpolation_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
965   PetscFunctionReturn(0);
966 }
967 
968 #undef __FUNCT__
969 #define __FUNCT__ "PCGAMGSetReuseInterpolation_GAMG"
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;
974 
975   PetscFunctionBegin;
976   pc_gamg->reuse_prol = n;
977   PetscFunctionReturn(0);
978 }
979 
980 #undef __FUNCT__
981 #define __FUNCT__ "PCGAMGSetUseASMAggs"
982 /*@
983    PCGAMGSetUseASMAggs -
984 
985    Collective on PC
986 
987    Input Parameters:
988 .  pc - the preconditioner context
989 
990 
991    Options Database Key:
992 .  -pc_gamg_use_agg_gasm
993 
994    Level: intermediate
995 
996    Concepts: Unstructured multigrid preconditioner
997 
998 .seealso: ()
999 @*/
1000 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1001 {
1002   PetscErrorCode ierr;
1003 
1004   PetscFunctionBegin;
1005   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1006   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1007   PetscFunctionReturn(0);
1008 }
1009 
1010 #undef __FUNCT__
1011 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
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;
1016 
1017   PetscFunctionBegin;
1018   pc_gamg->use_aggs_in_gasm = n;
1019   PetscFunctionReturn(0);
1020 }
1021 
1022 #undef __FUNCT__
1023 #define __FUNCT__ "PCGAMGSetNlevels"
1024 /*@
1025    PCGAMGSetNlevels -  Sets the maximum number of levels PCGAMG will use
1026 
1027    Not collective on PC
1028 
1029    Input Parameters:
1030 +  pc - the preconditioner
1031 -  n - the maximum number of levels to use
1032 
1033    Options Database Key:
1034 .  -pc_mg_levels
1035 
1036    Level: intermediate
1037 
1038    Concepts: Unstructured multigrid preconditioner
1039 
1040 .seealso: ()
1041 @*/
1042 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1043 {
1044   PetscErrorCode ierr;
1045 
1046   PetscFunctionBegin;
1047   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1048   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1049   PetscFunctionReturn(0);
1050 }
1051 
1052 #undef __FUNCT__
1053 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
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;
1058 
1059   PetscFunctionBegin;
1060   pc_gamg->Nlevels = n;
1061   PetscFunctionReturn(0);
1062 }
1063 
1064 #undef __FUNCT__
1065 #define __FUNCT__ "PCGAMGSetThreshold"
1066 /*@
1067    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph
1068 
1069    Not collective on PC
1070 
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
1074 
1075    Options Database Key:
1076 .  -pc_gamg_threshold <threshold>
1077 
1078    Level: intermediate
1079 
1080    Concepts: Unstructured multigrid preconditioner
1081 
1082 .seealso: ()
1083 @*/
1084 PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
1085 {
1086   PetscErrorCode ierr;
1087 
1088   PetscFunctionBegin;
1089   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1090   ierr = PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));CHKERRQ(ierr);
1091   PetscFunctionReturn(0);
1092 }
1093 
1094 #undef __FUNCT__
1095 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
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;
1100 
1101   PetscFunctionBegin;
1102   pc_gamg->threshold = n;
1103   PetscFunctionReturn(0);
1104 }
1105 
1106 #undef __FUNCT__
1107 #define __FUNCT__ "PCGAMGSetType"
1108 /*@
1109    PCGAMGSetType - Set solution method
1110 
1111    Collective on PC
1112 
1113    Input Parameters:
1114 +  pc - the preconditioner context
1115 -  type - PCGAMGAGG, PCGAMGGEO, or PCGAMGCLASSICAL
1116 
1117    Options Database Key:
1118 .  -pc_gamg_type <agg,geo,classical>
1119 
1120    Level: intermediate
1121 
1122    Concepts: Unstructured multigrid preconditioner
1123 
1124 .seealso: PCGAMGGetType(), PCGAMG
1125 @*/
1126 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1127 {
1128   PetscErrorCode ierr;
1129 
1130   PetscFunctionBegin;
1131   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1132   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1133   PetscFunctionReturn(0);
1134 }
1135 
1136 #undef __FUNCT__
1137 #define __FUNCT__ "PCGAMGGetType"
1138 /*@
1139    PCGAMGGetType - Get solution method
1140 
1141    Collective on PC
1142 
1143    Input Parameter:
1144 .  pc - the preconditioner context
1145 
1146    Output Parameter:
1147 .  type - the type of algorithm used
1148 
1149    Level: intermediate
1150 
1151    Concepts: Unstructured multigrid preconditioner
1152 
1153 .seealso: PCGAMGSetType(), PCGAMGType
1154 @*/
1155 PetscErrorCode PCGAMGGetType(PC pc, PCGAMGType *type)
1156 {
1157   PetscErrorCode ierr;
1158 
1159   PetscFunctionBegin;
1160   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1161   ierr = PetscUseMethod(pc,"PCGAMGGetType_C",(PC,PCGAMGType*),(pc,type));CHKERRQ(ierr);
1162   PetscFunctionReturn(0);
1163 }
1164 
1165 #undef __FUNCT__
1166 #define __FUNCT__ "PCGAMGGetType_GAMG"
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;
1171 
1172   PetscFunctionBegin;
1173   *type = pc_gamg->type;
1174   PetscFunctionReturn(0);
1175 }
1176 
1177 #undef __FUNCT__
1178 #define __FUNCT__ "PCGAMGSetType_GAMG"
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;
1184 
1185   PetscFunctionBegin;
1186   pc_gamg->type = type;
1187   ierr = PetscFunctionListFind(GAMGList,type,&r);CHKERRQ(ierr);
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     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1191     ierr = PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));CHKERRQ(ierr);
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     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1199     pc_gamg->data_sz = 0;
1200   }
1201   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1202   ierr = PetscStrallocpy(type,&pc_gamg->gamg_type_name);CHKERRQ(ierr);
1203   ierr = (*r)(pc);CHKERRQ(ierr);
1204   PetscFunctionReturn(0);
1205 }
1206 
1207 #undef __FUNCT__
1208 #define __FUNCT__ "PCView_GAMG"
1209 static PetscErrorCode PCView_GAMG(PC pc,PetscViewer viewer)
1210 {
1211   PetscErrorCode ierr;
1212   PC_MG          *mg      = (PC_MG*)pc->data;
1213   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1214 
1215   PetscFunctionBegin;
1216   ierr = PetscViewerASCIIPrintf(viewer,"    GAMG specific options\n");CHKERRQ(ierr);
1217   ierr = PetscViewerASCIIPrintf(viewer,"      Threshold for dropping small values from graph %g\n",(double)pc_gamg->threshold);CHKERRQ(ierr);
1218   if (pc_gamg->ops->view) {
1219     ierr = (*pc_gamg->ops->view)(pc,viewer);CHKERRQ(ierr);
1220   }
1221   PetscFunctionReturn(0);
1222 }
1223 
1224 #undef __FUNCT__
1225 #define __FUNCT__ "PCSetFromOptions_GAMG"
1226 PetscErrorCode PCSetFromOptions_GAMG(PetscOptions *PetscOptionsObject,PC pc)
1227 {
1228   PetscErrorCode ierr;
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;
1234 
1235   PetscFunctionBegin;
1236   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1237   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG options");CHKERRQ(ierr);
1238   {
1239     char tname[256];
1240     ierr = PetscOptionsFList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, pc_gamg->gamg_type_name, tname, sizeof(tname), &flag);CHKERRQ(ierr);
1241     if (flag) {
1242       ierr = PCGAMGSetType(pc,tname);CHKERRQ(ierr);
1243     }
1244     ierr = PetscOptionsBool("-pc_gamg_repartition","Repartion coarse grids","PCGAMGRepartitioning",pc_gamg->repart,&pc_gamg->repart,NULL);CHKERRQ(ierr);
1245     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation","Reuse prolongation operator","PCGAMGReuseInterpolation",pc_gamg->reuse_prol,&pc_gamg->reuse_prol,NULL);CHKERRQ(ierr);
1246     ierr = 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);CHKERRQ(ierr);
1247     ierr = 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);CHKERRQ(ierr);
1248     ierr = 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);CHKERRQ(ierr);
1249     ierr = PetscOptionsReal("-pc_gamg_threshold","Relative threshold to use for dropping edges in aggregation graph","PCGAMGSetThreshold",pc_gamg->threshold,&pc_gamg->threshold,&flag);CHKERRQ(ierr);
1250     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1251     ierr = PetscOptionsInt("-pc_mg_levels","Set number of MG levels","PCGAMGSetNlevels",pc_gamg->Nlevels,&pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
1252 
1253     /* set options for subtype */
1254     if (pc_gamg->ops->setfromoptions) {ierr = (*pc_gamg->ops->setfromoptions)(PetscOptionsObject,pc);CHKERRQ(ierr);}
1255   }
1256   ierr = PetscOptionsTail();CHKERRQ(ierr);
1257   PetscFunctionReturn(0);
1258 }
1259 
1260 /* -------------------------------------------------------------------------- */
1261 /*MC
1262      PCGAMG - Geometric algebraic multigrid (AMG) preconditioner
1263 
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
1270 
1271 
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
1276 
1277   Level: intermediate
1278 
1279   Concepts: algebraic multigrid
1280 
1281 .seealso:  PCCreate(), PCSetType(), MatSetBlockSize(), PCMGType, PCSetCoordinates(), MatSetNearNullSpace(), PCGAMGSetType(), PCGAMGAGG, PCGAMGGEO, PCGAMGCLASSICAL, PCGAMGSetProcEqLim(),
1282            PCGAMGSetCoarseEqLim(), PCGAMGSetRepartitioning(), PCGAMGRegister(), PCGAMGSetReuseInterpolation(), PCGAMGSetUseASMAggs(), PCGAMGSetNlevels(), PCGAMGSetThreshold(), PCGAMGGetType()
1283 M*/
1284 
1285 #undef __FUNCT__
1286 #define __FUNCT__ "PCCreate_GAMG"
1287 PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
1288 {
1289   PetscErrorCode ierr;
1290   PC_GAMG        *pc_gamg;
1291   PC_MG          *mg;
1292 
1293   PetscFunctionBegin;
1294   /* register AMG type */
1295   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1296 
1297   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1298   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr);
1299   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1300 
1301   /* create a supporting struct and attach it to pc */
1302   ierr         = PetscNewLog(pc,&pc_gamg);CHKERRQ(ierr);
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;
1306 
1307   ierr = PetscNewLog(pc,&pc_gamg->ops);CHKERRQ(ierr);
1308 
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;
1313 
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;
1320 
1321   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1322   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1323   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1324   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseInterpolation_C",PCGAMGSetReuseInterpolation_GAMG);CHKERRQ(ierr);
1325   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1326   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1327   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);CHKERRQ(ierr);
1328   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGGetType_C",PCGAMGGetType_GAMG);CHKERRQ(ierr);
1329   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);CHKERRQ(ierr);
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;
1342 
1343   /* PCSetUp_GAMG assumes that the type has been set, so set it to the default now */
1344   ierr = PCGAMGSetType(pc,PCGAMGAGG);CHKERRQ(ierr);
1345   PetscFunctionReturn(0);
1346 }
1347 
1348 #undef __FUNCT__
1349 #define __FUNCT__ "PCGAMGInitializePackage"
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.
1354 
1355  Level: developer
1356 
1357  .keywords: PC, PCGAMG, initialize, package
1358  .seealso: PetscInitialize()
1359 @*/
1360 PetscErrorCode PCGAMGInitializePackage(void)
1361 {
1362   PetscErrorCode ierr;
1363 
1364   PetscFunctionBegin;
1365   if (PCGAMGPackageInitialized) PetscFunctionReturn(0);
1366   PCGAMGPackageInitialized = PETSC_TRUE;
1367   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);CHKERRQ(ierr);
1368   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);CHKERRQ(ierr);
1369   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGCLASSICAL,PCCreateGAMG_Classical);CHKERRQ(ierr);
1370   ierr = PetscRegisterFinalize(PCGAMGFinalizePackage);CHKERRQ(ierr);
1371 
1372   /* general events */
1373   ierr = PetscLogEventRegister("PCGAMGGraph_AGG", 0, &PC_GAMGGraph_AGG);CHKERRQ(ierr);
1374   ierr = PetscLogEventRegister("PCGAMGGraph_GEO", PC_CLASSID, &PC_GAMGGraph_GEO);CHKERRQ(ierr);
1375   ierr = PetscLogEventRegister("PCGAMGCoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1376   ierr = PetscLogEventRegister("PCGAMGCoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1377   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1378   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1379   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptProlongator_AGG);CHKERRQ(ierr);
1380 
1381 #if defined PETSC_GAMG_USE_LOG
1382   ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1383   ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
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   ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1388   ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1389   ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1390   ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1391   ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1392   ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1393   ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1394   ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1395   ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1396   ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1397   ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1398   ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1399 
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     ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1410     for (lidx=1; lidx<9; lidx++) {
1411       sprintf(str,"MG Level %d",lidx);
1412       ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1413     }
1414   }
1415 #endif
1416 #endif
1417   PetscFunctionReturn(0);
1418 }
1419 
1420 #undef __FUNCT__
1421 #define __FUNCT__ "PCGAMGFinalizePackage"
1422 /*@C
1423  PCGAMGFinalizePackage - This function frees everything from the PCGAMG package. It is
1424     called from PetscFinalize() automatically.
1425 
1426  Level: developer
1427 
1428  .keywords: Petsc, destroy, package
1429  .seealso: PetscFinalize()
1430 @*/
1431 PetscErrorCode PCGAMGFinalizePackage(void)
1432 {
1433   PetscErrorCode ierr;
1434 
1435   PetscFunctionBegin;
1436   PCGAMGPackageInitialized = PETSC_FALSE;
1437   ierr = PetscFunctionListDestroy(&GAMGList);CHKERRQ(ierr);
1438   PetscFunctionReturn(0);
1439 }
1440 
1441 #undef __FUNCT__
1442 #define __FUNCT__ "PCGAMGRegister"
1443 /*@C
1444  PCGAMGRegister - Register a PCGAMG implementation.
1445 
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.
1449 
1450   Level: advanced
1451 
1452  .seealso: PCGAMGType, PCGAMG, PCGAMGSetType()
1453 @*/
1454 PetscErrorCode PCGAMGRegister(PCGAMGType type, PetscErrorCode (*create)(PC))
1455 {
1456   PetscErrorCode ierr;
1457 
1458   PetscFunctionBegin;
1459   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1460   ierr = PetscFunctionListAdd(&GAMGList,type,create);CHKERRQ(ierr);
1461   PetscFunctionReturn(0);
1462 }
1463 
1464