xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision b60d1aa9dffe7f0839cca942e8a5760aa5de1720)
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_GAMGGgraph_AGG;
15 PetscLogEvent PC_GAMGGgraph_GEO;
16 PetscLogEvent PC_GAMGCoarsen_AGG;
17 PetscLogEvent PC_GAMGCoarsen_GEO;
18 PetscLogEvent PC_GAMGProlongator_AGG;
19 PetscLogEvent PC_GAMGProlongator_GEO;
20 PetscLogEvent PC_GAMGOptprol_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 = NULL; pc_gamg->data_sz = 0;
48 
49   if (pc_gamg->orig_data) {
50     ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
51   }
52   PetscFunctionReturn(0);
53 }
54 
55 /* -------------------------------------------------------------------------- */
56 /*
57    PCGAMGCreateLevel_GAMG: create coarse op with RAP.  repartition and/or reduce number
58      of active processors.
59 
60    Input Parameter:
61    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
62           'pc_gamg->data_sz' are changed via repartitioning/reduction.
63    . Amat_fine - matrix on this fine (k) level
64    . cr_bs - coarse block size
65    In/Output Parameter:
66    . a_P_inout - prolongation operator to the next level (k-->k-1)
67    . a_nactive_proc - number of active procs
68    Output Parameter:
69    . a_Amat_crs - coarse matrix that is created (k-1)
70 */
71 
72 #undef __FUNCT__
73 #define __FUNCT__ "PCGAMGCreateLevel_GAMG"
74 static PetscErrorCode PCGAMGCreateLevel_GAMG(PC pc,Mat Amat_fine,PetscInt cr_bs,
75                                   Mat *a_P_inout,Mat *a_Amat_crs,PetscMPIInt *a_nactive_proc,
76                                   IS * Pcolumnperm)
77 {
78   PetscErrorCode  ierr;
79   PC_MG           *mg         = (PC_MG*)pc->data;
80   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
81   const PetscBool repart      = pc_gamg->repart;
82   const PetscInt  min_eq_proc = pc_gamg->min_eq_proc, coarse_max = pc_gamg->coarse_eq_limit;
83   Mat             Cmat,Pold=*a_P_inout;
84   MPI_Comm        comm;
85   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
86   PetscInt        ncrs_eq,ncrs,f_bs;
87 
88   PetscFunctionBegin;
89   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
90   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
91   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
92   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
93   /* RAP */
94   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
95 
96   /* set 'ncrs' (nodes), 'ncrs_eq' (equations)*/
97   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
98   if (pc_gamg->data_cell_rows>0) {
99     ncrs = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
100   }
101   else {
102     PetscInt  bs;
103     ierr = MatGetBlockSize(Cmat, &bs);CHKERRQ(ierr);
104     ncrs = ncrs_eq/bs;
105   }
106 
107   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
108   {
109     PetscInt ncrs_eq_glob;
110     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
111     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
112     if (new_size == 0 || ncrs_eq_glob < coarse_max) new_size = 1;
113     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
114   }
115 
116   if (Pcolumnperm) *Pcolumnperm = NULL;
117 
118   if (!repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
119   else {
120     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_new,ncrs_eq_new,nloc_old;
121     IS             is_eq_newproc,is_eq_num,is_eq_num_prim,new_eq_indices;
122 
123     nloc_old = ncrs_eq/cr_bs;
124     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);
125 #if defined PETSC_GAMG_USE_LOG
126     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
127 #endif
128     /* make 'is_eq_newproc' */
129     ierr = PetscMalloc1(size, &counts);CHKERRQ(ierr);
130     if (repart) {
131       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
132       Mat adj;
133 
134       if (pc_gamg->verbose>0) {
135         if (pc_gamg->verbose==1) PetscPrintf(comm,"\t[%d]%s repartition: size (active): %d --> %d, neq = %d\n",rank,__FUNCT__,*a_nactive_proc,new_size,ncrs_eq);
136         else {
137           PetscInt n;
138           ierr = MPI_Allreduce(&ncrs_eq, &n, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
139           PetscPrintf(comm,"\t[%d]%s repartition: size (active): %d --> %d, neq = %d\n",rank,__FUNCT__,*a_nactive_proc,new_size,n);
140         }
141       }
142 
143       /* get 'adj' */
144       if (cr_bs == 1) {
145         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
146       } else {
147         /* make a scalar matrix to partition (no Stokes here) */
148         Mat               tMat;
149         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
150         const PetscScalar *vals;
151         const PetscInt    *idx;
152         PetscInt          *d_nnz, *o_nnz, M, N;
153         static PetscInt   llev = 0;
154 
155         ierr = PetscMalloc1(ncrs, &d_nnz);CHKERRQ(ierr);
156         ierr = PetscMalloc1(ncrs, &o_nnz);CHKERRQ(ierr);
157         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
158         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
159         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
160           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
161           d_nnz[jj] = ncols/cr_bs;
162           o_nnz[jj] = ncols/cr_bs;
163           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
164           if (d_nnz[jj] > ncrs) d_nnz[jj] = ncrs;
165           if (o_nnz[jj] > (M/cr_bs-ncrs)) o_nnz[jj] = M/cr_bs-ncrs;
166         }
167 
168         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
169         ierr = MatSetSizes(tMat, ncrs, ncrs,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
170         ierr = MatSetType(tMat,MATAIJ);CHKERRQ(ierr);
171         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
172         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
173         ierr = PetscFree(d_nnz);CHKERRQ(ierr);
174         ierr = PetscFree(o_nnz);CHKERRQ(ierr);
175 
176         for (ii = Istart_crs; ii < Iend_crs; ii++) {
177           PetscInt dest_row = ii/cr_bs;
178           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
179           for (jj = 0; jj < ncols; jj++) {
180             PetscInt    dest_col = idx[jj]/cr_bs;
181             PetscScalar v        = 1.0;
182             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
183           }
184           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
185         }
186         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
187         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
188 
189         if (llev++ == -1) {
190           PetscViewer viewer; char fname[32];
191           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
192           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
193           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
194           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
195         }
196 
197         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
198 
199         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
200       } /* create 'adj' */
201 
202       { /* partition: get newproc_idx */
203         char            prefix[256];
204         const char      *pcpre;
205         const PetscInt  *is_idx;
206         MatPartitioning mpart;
207         IS              proc_is;
208         PetscInt        targetPE;
209 
210         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
211         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
212         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
213         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
214         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
215         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
216         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
217         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
218         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
219 
220         /* collect IS info */
221         ierr     = PetscMalloc1(ncrs_eq, &newproc_idx);CHKERRQ(ierr);
222         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
223         targetPE = 1; /* bring to "front" of machine */
224         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
225         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
226           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
227             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
228           }
229         }
230         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
231         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
232       }
233       ierr = MatDestroy(&adj);CHKERRQ(ierr);
234 
235       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
236       if (newproc_idx != 0) {
237         ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
238       }
239     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
240 
241       PetscInt rfactor,targetPE;
242       /* find factor */
243       if (new_size == 1) rfactor = size; /* easy */
244       else {
245         PetscReal best_fact = 0.;
246         jj = -1;
247         for (kk = 1 ; kk <= size ; kk++) {
248           if (size%kk==0) { /* a candidate */
249             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
250             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
251             if (fact > best_fact) {
252               best_fact = fact; jj = kk;
253             }
254           }
255         }
256         if (jj != -1) rfactor = jj;
257         else rfactor = 1; /* does this happen .. a prime */
258       }
259       new_size = size/rfactor;
260 
261       if (new_size==nactive) {
262         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
263         ierr        = PetscFree(counts);CHKERRQ(ierr);
264         if (pc_gamg->verbose>0) {
265           PetscPrintf(comm,"\t[%d]%s aggregate processors noop: new_size=%d, neq(loc)=%d\n",rank,__FUNCT__,new_size,ncrs_eq);
266         }
267         PetscFunctionReturn(0);
268       }
269 
270       if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s number of equations (loc) %d with simple aggregation\n",rank,__FUNCT__,ncrs_eq);
271       targetPE = rank/rfactor;
272       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
273     } /* end simple 'is_eq_newproc' */
274 
275     /*
276      Create an index set from the is_eq_newproc index set to indicate the mapping TO
277      */
278     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
279     is_eq_num_prim = is_eq_num;
280     /*
281       Determine how many equations/vertices are assigned to each processor
282      */
283     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
284     ncrs_eq_new = counts[rank];
285     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
286     ncrs_new = ncrs_eq_new/cr_bs; /* eqs */
287 
288     ierr = PetscFree(counts);CHKERRQ(ierr);
289 #if defined PETSC_GAMG_USE_LOG
290     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
291 #endif
292     /* 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 */
293     {
294     Vec            src_crd, dest_crd;
295     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
296     VecScatter     vecscat;
297     PetscScalar    *array;
298     IS isscat;
299 
300     /* move data (for primal equations only) */
301     /* Create a vector to contain the newly ordered element information */
302     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
303     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_new, PETSC_DECIDE);CHKERRQ(ierr);
304     ierr = VecSetType(dest_crd,VECSTANDARD);CHKERRQ(ierr); /* this is needed! */
305     /*
306      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
307      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
308      */
309     ierr = PetscMalloc1(ncrs*node_data_sz, &tidx);CHKERRQ(ierr);
310     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
311     for (ii=0,jj=0; ii<ncrs; ii++) {
312       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
313       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
314     }
315     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
316     ierr = ISCreateGeneral(comm, node_data_sz*ncrs, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
317     ierr = PetscFree(tidx);CHKERRQ(ierr);
318     /*
319      Create a vector to contain the original vertex information for each element
320      */
321     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs, &src_crd);CHKERRQ(ierr);
322     for (jj=0; jj<ndata_cols; jj++) {
323       const PetscInt stride0=ncrs*pc_gamg->data_cell_rows;
324       for (ii=0; ii<ncrs; ii++) {
325         for (kk=0; kk<ndata_rows; kk++) {
326           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
327           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
328           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
329         }
330       }
331     }
332     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
333     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
334     /*
335       Scatter the element vertex information (still in the original vertex ordering)
336       to the correct processor
337     */
338     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
339     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
340     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
341     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
342     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
343     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
344     /*
345       Put the element vertex data into a new allocation of the gdata->ele
346     */
347     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
348     ierr = PetscMalloc1(node_data_sz*ncrs_new, &pc_gamg->data);CHKERRQ(ierr);
349 
350     pc_gamg->data_sz = node_data_sz*ncrs_new;
351     strideNew        = ncrs_new*ndata_rows;
352 
353     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
354     for (jj=0; jj<ndata_cols; jj++) {
355       for (ii=0; ii<ncrs_new; ii++) {
356         for (kk=0; kk<ndata_rows; kk++) {
357           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
358           pc_gamg->data[ix] = PetscRealPart(array[jx]);
359         }
360       }
361     }
362     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
363     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
364     }
365     /* move A and P (columns) with new layout */
366 #if defined PETSC_GAMG_USE_LOG
367     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
368 #endif
369 
370     /*
371       Invert for MatGetSubMatrix
372     */
373     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
374     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
375     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
376     if (is_eq_num != is_eq_num_prim) {
377       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
378     }
379     if (Pcolumnperm) {
380       ierr = PetscObjectReference((PetscObject)new_eq_indices);CHKERRQ(ierr);
381       *Pcolumnperm = new_eq_indices;
382     }
383     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
384 #if defined PETSC_GAMG_USE_LOG
385     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
386     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
387 #endif
388     /* 'a_Amat_crs' output */
389     {
390       Mat mat;
391       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
392       *a_Amat_crs = mat;
393 
394       if (!PETSC_TRUE) {
395         PetscInt cbs, rbs;
396         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
397         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
398         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
399         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);
400       }
401     }
402     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
403 
404 #if defined PETSC_GAMG_USE_LOG
405     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
406 #endif
407     /* prolongator */
408     {
409       IS       findices;
410       PetscInt Istart,Iend;
411       Mat      Pnew;
412       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
413 #if defined PETSC_GAMG_USE_LOG
414       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
415 #endif
416       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
417       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
418       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
419       ierr = ISDestroy(&findices);CHKERRQ(ierr);
420 
421       if (!PETSC_TRUE) {
422         PetscInt cbs, rbs;
423         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
424         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
425         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
426         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
427       }
428 #if defined PETSC_GAMG_USE_LOG
429       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
430 #endif
431       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
432 
433       /* output - repartitioned */
434       *a_P_inout = Pnew;
435     }
436     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
437 
438     *a_nactive_proc = new_size; /* output */
439   }
440 
441   /* outout matrix data */
442   if (!PETSC_TRUE) {
443     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
444     if (llev==0) {
445       sprintf(fname,"Cmat_%d.m",llev++);
446       PetscViewerASCIIOpen(comm,fname,&viewer);
447       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
448       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
449       ierr = PetscViewerDestroy(&viewer);
450     }
451     sprintf(fname,"Cmat_%d.m",llev++);
452     PetscViewerASCIIOpen(comm,fname,&viewer);
453     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
454     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
455     ierr = PetscViewerDestroy(&viewer);
456   }
457   PetscFunctionReturn(0);
458 }
459 
460 /* -------------------------------------------------------------------------- */
461 /*
462    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
463                     by setting data structures and options.
464 
465    Input Parameter:
466 .  pc - the preconditioner context
467 
468    Application Interface Routine: PCSetUp()
469 
470    Notes:
471    The interface routine PCSetUp() is not usually called directly by
472    the user, but instead is called by PCApply() if necessary.
473 */
474 #undef __FUNCT__
475 #define __FUNCT__ "PCSetUp_GAMG"
476 PetscErrorCode PCSetUp_GAMG(PC pc)
477 {
478   PetscErrorCode ierr;
479   PC_MG          *mg      = (PC_MG*)pc->data;
480   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
481   Mat            Pmat     = pc->pmat;
482   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
483   MPI_Comm       comm;
484   PetscMPIInt    rank,size,nactivepe;
485   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
486   PetscReal      emaxs[GAMG_MAXLEVELS];
487   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
488   PetscLogDouble nnz0=0.,nnztot=0.;
489   MatInfo        info;
490   PetscBool      redo_mesh_setup = (PetscBool)(!pc_gamg->reuse_prol);
491 
492   PetscFunctionBegin;
493   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
494   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
495   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
496 
497   if (pc_gamg->verbose>2) PetscPrintf(comm,"[%d]%s pc_gamg->setup_count=%d pc->setupcalled=%d\n",rank,__FUNCT__,pc_gamg->setup_count,pc->setupcalled);
498 
499   if (pc_gamg->setup_count++ > 0) {
500     if (redo_mesh_setup) {
501       /* reset everything */
502       ierr = PCReset_MG(pc);CHKERRQ(ierr);
503       pc->setupcalled = 0;
504     } else {
505       PC_MG_Levels **mglevels = mg->levels;
506       /* just do Galerkin grids */
507       Mat          B,dA,dB;
508 
509      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
510       if (pc_gamg->Nlevels > 1) {
511         /* currently only handle case where mat and pmat are the same on coarser levels */
512         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB);CHKERRQ(ierr);
513         /* (re)set to get dirty flag */
514         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB);CHKERRQ(ierr);
515 
516         for (level=pc_gamg->Nlevels-2; level>=0; level--) {
517           /* the first time through the matrix structure has changed from repartitioning */
518           if (pc_gamg->setup_count==2) {
519             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
520             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
521 
522             mglevels[level]->A = B;
523           } else {
524             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B);CHKERRQ(ierr);
525             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
526           }
527           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B);CHKERRQ(ierr);
528           dB   = B;
529         }
530       }
531 
532       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
533 
534       PetscFunctionReturn(0);
535     }
536   }
537 
538   if (!pc_gamg->data) {
539     if (pc_gamg->orig_data) {
540       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
541       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
542 
543       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
544       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
545       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;
546 
547       ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->data);CHKERRQ(ierr);
548       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
549     } else {
550       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
551       ierr = pc_gamg->ops->createdefaultdata(pc,Pmat);CHKERRQ(ierr);
552     }
553   }
554 
555   /* cache original data for reuse */
556   if (!pc_gamg->orig_data && redo_mesh_setup) {
557     ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->orig_data);CHKERRQ(ierr);
558     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
559     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
560     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
561   }
562 
563   /* get basic dims */
564   ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
565 
566   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
567   if (pc_gamg->verbose) {
568     PetscInt NN = M;
569     if (pc_gamg->verbose==1) {
570       ierr =  MatGetInfo(Pmat,MAT_LOCAL,&info);CHKERRQ(ierr);
571       ierr = MatGetLocalSize(Pmat, &NN, &qq);CHKERRQ(ierr);
572       if (!NN) NN=1;
573     } else {
574       ierr = MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr);
575     }
576     nnz0   = info.nz_used;
577     nnztot = info.nz_used;
578     ierr   = PetscPrintf(comm,"\t[%d]%s level %d N=%d, n data rows=%d, n data cols=%d, nnz/row (ave)=%d, np=%d\n",
579                          rank,__FUNCT__,0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
580                          (int)(nnz0/(PetscReal)NN),size);CHKERRQ(ierr);
581   }
582 
583   /* Get A_i and R_i */
584   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
585        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);  /* && (size==1 || nactivepe>1); */
586        level++) {
587     pc_gamg->firstCoarsen = (level ? PETSC_FALSE : PETSC_TRUE);
588     level1 = level + 1;
589 #if defined PETSC_GAMG_USE_LOG
590     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
591 #if (defined GAMG_STAGES)
592     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
593 #endif
594 #endif
595     { /* construct prolongator */
596       Mat              Gmat;
597       PetscCoarsenData *agg_lists;
598       Mat              Prol11;
599 
600       ierr = pc_gamg->ops->graph(pc,Aarr[level], &Gmat);CHKERRQ(ierr);
601       ierr = pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
602       ierr = pc_gamg->ops->prolongator(pc,Aarr[level],Gmat,agg_lists,&Prol11);CHKERRQ(ierr);
603 
604       /* could have failed to create new level */
605       if (Prol11) {
606         /* get new block size of coarse matrices */
607         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
608 
609         if (pc_gamg->ops->optprol) {
610           /* smooth */
611           ierr = pc_gamg->ops->optprol(pc, Aarr[level], &Prol11);CHKERRQ(ierr);
612         }
613 
614         Parr[level1] = Prol11;
615       } else Parr[level1] = NULL;
616 
617       if (pc_gamg->use_aggs_in_gasm) {
618         PetscInt bs;
619         ierr = MatGetBlockSizes(Prol11, &bs, NULL);CHKERRQ(ierr);
620         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
621       }
622 
623       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
624       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
625     } /* construct prolongator scope */
626 #if defined PETSC_GAMG_USE_LOG
627     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
628 #endif
629     /* cache eigen estimate */
630     if (pc_gamg->emax_id != -1) {
631       PetscBool flag;
632       ierr = PetscObjectComposedDataGetReal((PetscObject)Aarr[level], pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
633       if (!flag) emaxs[level] = -1.;
634     } else emaxs[level] = -1.;
635     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
636     if (!Parr[level1]) {
637       if (pc_gamg->verbose) {
638         ierr =  PetscPrintf(comm,"\t[%d]%s stop gridding, level %d\n",rank,__FUNCT__,level);CHKERRQ(ierr);
639       }
640       break;
641     }
642 #if defined PETSC_GAMG_USE_LOG
643     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
644 #endif
645 
646     ierr = pc_gamg->ops->createlevel(pc, Aarr[level], bs,
647                        &Parr[level1], &Aarr[level1], &nactivepe, NULL);CHKERRQ(ierr);
648 
649 #if defined PETSC_GAMG_USE_LOG
650     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
651 #endif
652     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
653 
654     if (pc_gamg->verbose > 0) {
655       PetscInt NN = M;
656       if (pc_gamg->verbose==1) {
657         ierr = MatGetInfo(Aarr[level1],MAT_LOCAL,&info);CHKERRQ(ierr);
658         ierr = MatGetLocalSize(Aarr[level1], &NN, &qq);CHKERRQ(ierr);
659         if (!NN) NN=1;
660       } else {
661         ierr = MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
662       }
663 
664       nnztot += info.nz_used;
665       ierr    = PetscPrintf(comm,"\t\t[%d]%s %d) N=%d, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",
666                             rank,__FUNCT__,(int)level1,M,pc_gamg->data_cell_cols,
667                             (int)(info.nz_used/(PetscReal)NN), nactivepe);CHKERRQ(ierr);
668     }
669 
670     /* stop if one node or one proc -- could pull back for singular problems */
671     if ( (pc_gamg->data_cell_cols && M/pc_gamg->data_cell_cols < 2) || (!pc_gamg->data_cell_cols && M < 2)
672          || nactivepe==1 ) {
673       level++;
674       break;
675     }
676 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
677     ierr = PetscLogStagePop();CHKERRQ(ierr);
678 #endif
679   } /* levels */
680   pc_gamg->firstCoarsen = PETSC_FALSE;
681 
682   if (pc_gamg->data) {
683     ierr          = PetscFree(pc_gamg->data);CHKERRQ(ierr);
684     pc_gamg->data = NULL;
685   }
686 
687   if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s %d levels, grid complexity = %g\n",0,__FUNCT__,level+1,nnztot/nnz0);
688   pc_gamg->Nlevels = level + 1;
689   fine_level       = level;
690   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
691 
692   /* simple setup */
693   if (!PETSC_TRUE) {
694     PC_MG_Levels **mglevels = mg->levels;
695     for (lidx=0,level=pc_gamg->Nlevels-1;
696          lidx<fine_level;
697          lidx++, level--) {
698       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
699       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level]);CHKERRQ(ierr);
700       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
701       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
702     }
703     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0]);CHKERRQ(ierr);
704 
705     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
706   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
707     /* set default smoothers & set operators */
708     for (lidx = 1, level = pc_gamg->Nlevels-2;
709          lidx <= fine_level;
710          lidx++, level--) {
711       KSP smoother;
712       PC  subpc;
713 
714       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
715       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
716 
717       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
718       /* set ops */
719       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level]);CHKERRQ(ierr);
720       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
721 
722       /* set defaults */
723       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
724 
725       /* set blocks for GASM smoother that uses the 'aggregates' */
726       if (pc_gamg->use_aggs_in_gasm) {
727         PetscInt sz;
728         IS       *is;
729 
730         sz   = nASMBlocksArr[level];
731         is   = ASMLocalIDsArr[level];
732         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
733         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
734         if (sz==0) {
735           IS       is;
736           PetscInt my0,kk;
737           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
738           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
739           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
740           ierr = ISDestroy(&is);CHKERRQ(ierr);
741         } else {
742           PetscInt kk;
743           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
744           for (kk=0; kk<sz; kk++) {
745             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
746           }
747           ierr = PetscFree(is);CHKERRQ(ierr);
748         }
749         ASMLocalIDsArr[level] = NULL;
750         nASMBlocksArr[level]  = 0;
751         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
752       } else {
753         ierr = PCSetType(subpc, PCSOR);CHKERRQ(ierr);
754       }
755     }
756     {
757       /* coarse grid */
758       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
759       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
760       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
761       ierr = KSPSetOperators(smoother, Lmat, Lmat);CHKERRQ(ierr);
762       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
763       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
764       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
765       ierr = PCSetUp(subpc);CHKERRQ(ierr);
766       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
767       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
768       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
769       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
770       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
771       ierr = KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);CHKERRQ(ierr);
772       /* This flag gets reset by PCBJacobiGetSubKSP(), but our BJacobi really does the same algorithm everywhere (and in
773        * fact, all but one process will have zero dofs), so we reset the flag to avoid having PCView_BJacobi attempt to
774        * view every subdomain as though they were different. */
775       ((PC_BJacobi*)subpc->data)->same_local_solves = PETSC_TRUE;
776     }
777 
778     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
779     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
780     ierr = PCSetFromOptions_MG(PetscOptionsObject,pc);CHKERRQ(ierr);
781     ierr = PetscOptionsEnd();CHKERRQ(ierr);
782     if (mg->galerkin != 2) SETERRQ(comm,PETSC_ERR_USER,"GAMG does Galerkin manually so the -pc_mg_galerkin option must not be used.");
783 
784     /* create cheby smoothers */
785     for (lidx = 1, level = pc_gamg->Nlevels-2;
786          lidx <= fine_level;
787          lidx++, level--) {
788       KSP       smoother;
789       PetscBool flag,flag2;
790       PC        subpc;
791 
792       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
793       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
794 
795       /* do my own cheby */
796       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
797       if (flag) {
798         PetscReal emax, emin;
799         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
800         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCSOR, &flag2);CHKERRQ(ierr);
801         if ((flag||flag2) && emaxs[level] > 0.0) emax=emaxs[level]; /* eigen estimate only for diagnal PC but lets acccept SOR because it is close and safe (always lower) */
802         else { /* eigen estimate 'emax' -- this is done in cheby */
803           KSP eksp;
804           Mat Lmat = Aarr[level];
805           Vec bb, xx;
806 
807           ierr = MatCreateVecs(Lmat, &bb, 0);CHKERRQ(ierr);
808           ierr = MatCreateVecs(Lmat, &xx, 0);CHKERRQ(ierr);
809           {
810             PetscRandom rctx;
811             ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
812             ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
813             ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
814             ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
815           }
816 
817           /* zeroing out BC rows -- needed for crazy matrices */
818           {
819             PetscInt    Istart,Iend,ncols,jj,Ii;
820             PetscScalar zero = 0.0;
821             ierr = MatGetOwnershipRange(Lmat, &Istart, &Iend);CHKERRQ(ierr);
822             for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
823               ierr = MatGetRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
824               if (ncols <= 1) {
825                 ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
826               }
827               ierr = MatRestoreRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
828             }
829             ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
830             ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
831           }
832 
833           ierr = KSPCreate(comm, &eksp);CHKERRQ(ierr);
834           ierr = KSPSetTolerances(eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10);CHKERRQ(ierr);
835           ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
836           ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
837           ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
838           ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
839 
840           ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
841           ierr = KSPSetOperators(eksp, Lmat, Lmat);CHKERRQ(ierr);
842           ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
843 
844           /* set PC type to be same as smoother */
845           ierr = KSPSetPC(eksp, subpc);CHKERRQ(ierr);
846 
847           /* solve - keep stuff out of logging */
848           ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
849           ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
850           ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
851           ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
852           ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
853 
854           ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
855 
856           ierr = VecDestroy(&xx);CHKERRQ(ierr);
857           ierr = VecDestroy(&bb);CHKERRQ(ierr);
858           ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
859 
860           if (pc_gamg->verbose > 0) {
861             PetscInt N1, tt;
862             ierr = MatGetSize(Aarr[level], &N1, &tt);CHKERRQ(ierr);
863             PetscPrintf(comm,"\t\t\t%s PC setup max eigen=%e min=%e on level %d (N=%d)\n",__FUNCT__,emax,emin,lidx,N1);
864           }
865         }
866         {
867           PetscInt N1, N0;
868           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
869           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
870           /* heuristic - is this crap? */
871           /* emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); */
872           emin  = emax * pc_gamg->eigtarget[0];
873           emax *= pc_gamg->eigtarget[1];
874         }
875         ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
876       } /* setup checby flag */
877     } /* non-coarse levels */
878 
879     /* clean up */
880     for (level=1; level<pc_gamg->Nlevels; level++) {
881       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
882       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
883     }
884 
885     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
886   } else {
887     KSP smoother;
888     if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s one level solver used (system is seen as DD). Using default solver.\n",rank,__FUNCT__);
889     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
890     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0]);CHKERRQ(ierr);
891     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
892     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
893   }
894   PetscFunctionReturn(0);
895 }
896 
897 /* ------------------------------------------------------------------------- */
898 /*
899  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
900    that was created with PCCreate_GAMG().
901 
902    Input Parameter:
903 .  pc - the preconditioner context
904 
905    Application Interface Routine: PCDestroy()
906 */
907 #undef __FUNCT__
908 #define __FUNCT__ "PCDestroy_GAMG"
909 PetscErrorCode PCDestroy_GAMG(PC pc)
910 {
911   PetscErrorCode ierr;
912   PC_MG          *mg     = (PC_MG*)pc->data;
913   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
914 
915   PetscFunctionBegin;
916   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
917   if (pc_gamg->ops->destroy) {
918     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
919   }
920   ierr = PetscFree(pc_gamg->ops);CHKERRQ(ierr);
921   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
922   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
923   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
924   PetscFunctionReturn(0);
925 }
926 
927 
928 #undef __FUNCT__
929 #define __FUNCT__ "PCGAMGSetProcEqLim"
930 /*@
931    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via processor reduction.
932 
933    Logically Collective on PC
934 
935    Input Parameters:
936 +  pc - the preconditioner context
937 -  n - the number of equations
938 
939 
940    Options Database Key:
941 .  -pc_gamg_process_eq_limit <limit>
942 
943    Level: intermediate
944 
945    Concepts: Unstructured multrigrid preconditioner
946 
947 .seealso: ()
948 @*/
949 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
950 {
951   PetscErrorCode ierr;
952 
953   PetscFunctionBegin;
954   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
955   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
956   PetscFunctionReturn(0);
957 }
958 
959 #undef __FUNCT__
960 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
961 static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
962 {
963   PC_MG   *mg      = (PC_MG*)pc->data;
964   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
965 
966   PetscFunctionBegin;
967   if (n>0) pc_gamg->min_eq_proc = n;
968   PetscFunctionReturn(0);
969 }
970 
971 #undef __FUNCT__
972 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
973 /*@
974    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
975 
976  Collective on PC
977 
978    Input Parameters:
979 +  pc - the preconditioner context
980 -  n - maximum number of equations to aim for
981 
982    Options Database Key:
983 .  -pc_gamg_coarse_eq_limit <limit>
984 
985    Level: intermediate
986 
987    Concepts: Unstructured multrigrid preconditioner
988 
989 @*/
990 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
991 {
992   PetscErrorCode ierr;
993 
994   PetscFunctionBegin;
995   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
996   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
997   PetscFunctionReturn(0);
998 }
999 
1000 #undef __FUNCT__
1001 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
1002 static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
1003 {
1004   PC_MG   *mg      = (PC_MG*)pc->data;
1005   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1006 
1007   PetscFunctionBegin;
1008   if (n>0) pc_gamg->coarse_eq_limit = n;
1009   PetscFunctionReturn(0);
1010 }
1011 
1012 #undef __FUNCT__
1013 #define __FUNCT__ "PCGAMGSetRepartitioning"
1014 /*@
1015    PCGAMGSetRepartitioning - Repartition the coarse grids
1016 
1017    Collective on PC
1018 
1019    Input Parameters:
1020 +  pc - the preconditioner context
1021 -  n - PETSC_TRUE or PETSC_FALSE
1022 
1023    Options Database Key:
1024 .  -pc_gamg_repartition <true,false>
1025 
1026    Level: intermediate
1027 
1028    Concepts: Unstructured multrigrid preconditioner
1029 
1030 .seealso: ()
1031 @*/
1032 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
1033 {
1034   PetscErrorCode ierr;
1035 
1036   PetscFunctionBegin;
1037   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1038   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1039   PetscFunctionReturn(0);
1040 }
1041 
1042 #undef __FUNCT__
1043 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
1044 static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
1045 {
1046   PC_MG   *mg      = (PC_MG*)pc->data;
1047   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1048 
1049   PetscFunctionBegin;
1050   pc_gamg->repart = n;
1051   PetscFunctionReturn(0);
1052 }
1053 
1054 #undef __FUNCT__
1055 #define __FUNCT__ "PCGAMGSetReuseInterpolation"
1056 /*@
1057    PCGAMGSetReuseInterpolation - Reuse prolongation when rebuilding preconditioner
1058 
1059    Collective on PC
1060 
1061    Input Parameters:
1062 +  pc - the preconditioner context
1063 -  n - PETSC_TRUE or PETSC_FALSE
1064 
1065    Options Database Key:
1066 .  -pc_gamg_reuse_interpolation <true,false>
1067 
1068    Level: intermediate
1069 
1070    Concepts: Unstructured multrigrid preconditioner
1071 
1072 .seealso: ()
1073 @*/
1074 PetscErrorCode PCGAMGSetReuseInterpolation(PC pc, PetscBool n)
1075 {
1076   PetscErrorCode ierr;
1077 
1078   PetscFunctionBegin;
1079   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1080   ierr = PetscTryMethod(pc,"PCGAMGSetReuseInterpolation_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1081   PetscFunctionReturn(0);
1082 }
1083 
1084 #undef __FUNCT__
1085 #define __FUNCT__ "PCGAMGSetReuseInterpolation_GAMG"
1086 static PetscErrorCode PCGAMGSetReuseInterpolation_GAMG(PC pc, PetscBool n)
1087 {
1088   PC_MG   *mg      = (PC_MG*)pc->data;
1089   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1090 
1091   PetscFunctionBegin;
1092   pc_gamg->reuse_prol = n;
1093   PetscFunctionReturn(0);
1094 }
1095 
1096 #undef __FUNCT__
1097 #define __FUNCT__ "PCGAMGSetUseASMAggs"
1098 /*@
1099    PCGAMGSetUseASMAggs -
1100 
1101    Collective on PC
1102 
1103    Input Parameters:
1104 .  pc - the preconditioner context
1105 
1106 
1107    Options Database Key:
1108 .  -pc_gamg_use_agg_gasm
1109 
1110    Level: intermediate
1111 
1112    Concepts: Unstructured multrigrid preconditioner
1113 
1114 .seealso: ()
1115 @*/
1116 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1117 {
1118   PetscErrorCode ierr;
1119 
1120   PetscFunctionBegin;
1121   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1122   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1123   PetscFunctionReturn(0);
1124 }
1125 
1126 #undef __FUNCT__
1127 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
1128 static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
1129 {
1130   PC_MG   *mg      = (PC_MG*)pc->data;
1131   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1132 
1133   PetscFunctionBegin;
1134   pc_gamg->use_aggs_in_gasm = n;
1135   PetscFunctionReturn(0);
1136 }
1137 
1138 #undef __FUNCT__
1139 #define __FUNCT__ "PCGAMGSetNlevels"
1140 /*@
1141    PCGAMGSetNlevels -  Sets the maximum number of levels PCGAMG will use
1142 
1143    Not collective on PC
1144 
1145    Input Parameters:
1146 +  pc - the preconditioner
1147 -  n - the maximum number of levels to use
1148 
1149    Options Database Key:
1150 .  -pc_mg_levels
1151 
1152    Level: intermediate
1153 
1154    Concepts: Unstructured multrigrid preconditioner
1155 
1156 .seealso: ()
1157 @*/
1158 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1159 {
1160   PetscErrorCode ierr;
1161 
1162   PetscFunctionBegin;
1163   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1164   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1165   PetscFunctionReturn(0);
1166 }
1167 
1168 #undef __FUNCT__
1169 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
1170 static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
1171 {
1172   PC_MG   *mg      = (PC_MG*)pc->data;
1173   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1174 
1175   PetscFunctionBegin;
1176   pc_gamg->Nlevels = n;
1177   PetscFunctionReturn(0);
1178 }
1179 
1180 #undef __FUNCT__
1181 #define __FUNCT__ "PCGAMGSetThreshold"
1182 /*@
1183    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph
1184 
1185    Not collective on PC
1186 
1187    Input Parameters:
1188 +  pc - the preconditioner context
1189 -  threshold - the threshold value, 0.0 is the lowest possible
1190 
1191    Options Database Key:
1192 .  -pc_gamg_threshold <threshold>
1193 
1194    Level: intermediate
1195 
1196    Concepts: Unstructured multrigrid preconditioner
1197 
1198 .seealso: ()
1199 @*/
1200 PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
1201 {
1202   PetscErrorCode ierr;
1203 
1204   PetscFunctionBegin;
1205   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1206   ierr = PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));CHKERRQ(ierr);
1207   PetscFunctionReturn(0);
1208 }
1209 
1210 #undef __FUNCT__
1211 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
1212 static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
1213 {
1214   PC_MG   *mg      = (PC_MG*)pc->data;
1215   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1216 
1217   PetscFunctionBegin;
1218   pc_gamg->threshold = n;
1219   PetscFunctionReturn(0);
1220 }
1221 
1222 #undef __FUNCT__
1223 #define __FUNCT__ "PCGAMGSetType"
1224 /*@
1225    PCGAMGSetType - Set solution method
1226 
1227    Collective on PC
1228 
1229    Input Parameters:
1230 +  pc - the preconditioner context
1231 -  type - PCGAMGAGG, PCGAMGGEO, or PCGAMGCLASSICAL
1232 
1233    Options Database Key:
1234 .  -pc_gamg_type <agg,geo,classical>
1235 
1236    Level: intermediate
1237 
1238    Concepts: Unstructured multrigrid preconditioner
1239 
1240 .seealso: PCGAMGGetType(), PCGAMG
1241 @*/
1242 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1243 {
1244   PetscErrorCode ierr;
1245 
1246   PetscFunctionBegin;
1247   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1248   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1249   PetscFunctionReturn(0);
1250 }
1251 
1252 #undef __FUNCT__
1253 #define __FUNCT__ "PCGAMGGetType"
1254 /*@
1255    PCGAMGGetType - Get solution method
1256 
1257    Collective on PC
1258 
1259    Input Parameter:
1260 .  pc - the preconditioner context
1261 
1262    Output Parameter:
1263 .  type - the type of algorithm used
1264 
1265    Level: intermediate
1266 
1267    Concepts: Unstructured multrigrid preconditioner
1268 
1269 .seealso: PCGAMGSetType()
1270 @*/
1271 PetscErrorCode PCGAMGGetType(PC pc, PCGAMGType *type)
1272 {
1273   PetscErrorCode ierr;
1274 
1275   PetscFunctionBegin;
1276   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1277   ierr = PetscUseMethod(pc,"PCGAMGGetType_C",(PC,PCGAMGType*),(pc,type));CHKERRQ(ierr);
1278   PetscFunctionReturn(0);
1279 }
1280 
1281 #undef __FUNCT__
1282 #define __FUNCT__ "PCGAMGGetType_GAMG"
1283 static PetscErrorCode PCGAMGGetType_GAMG(PC pc, PCGAMGType *type)
1284 {
1285   PC_MG          *mg      = (PC_MG*)pc->data;
1286   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1287 
1288   PetscFunctionBegin;
1289   *type = pc_gamg->type;
1290   PetscFunctionReturn(0);
1291 }
1292 
1293 #undef __FUNCT__
1294 #define __FUNCT__ "PCGAMGSetType_GAMG"
1295 static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
1296 {
1297   PetscErrorCode ierr,(*r)(PC);
1298   PC_MG          *mg      = (PC_MG*)pc->data;
1299   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1300 
1301   PetscFunctionBegin;
1302   pc_gamg->type = type;
1303   ierr = PetscFunctionListFind(GAMGList,type,&r);CHKERRQ(ierr);
1304   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
1305   if (pc_gamg->ops->destroy) {
1306     /* there was something here - kill it */
1307     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1308     ierr = PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));CHKERRQ(ierr);
1309     pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
1310     /* cleaning up common data in pc_gamg - this should disapear someday */
1311     pc_gamg->data_cell_cols = 0;
1312     pc_gamg->data_cell_rows = 0;
1313     pc_gamg->orig_data_cell_cols = 0;
1314     pc_gamg->orig_data_cell_rows = 0;
1315     if (pc_gamg->data_sz) {
1316       ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1317       pc_gamg->data_sz = 0;
1318     } else if (pc_gamg->data) {
1319       ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr); /* can this happen ? */
1320     }
1321   }
1322   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1323   ierr = PetscStrallocpy(type,&pc_gamg->gamg_type_name);CHKERRQ(ierr);
1324   ierr = (*r)(pc);CHKERRQ(ierr);
1325   PetscFunctionReturn(0);
1326 }
1327 
1328 #undef __FUNCT__
1329 #define __FUNCT__ "PCSetFromOptions_GAMG"
1330 PetscErrorCode PCSetFromOptions_GAMG(PetscOptions *PetscOptionsObject,PC pc)
1331 {
1332   PetscErrorCode ierr;
1333   PC_MG          *mg      = (PC_MG*)pc->data;
1334   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1335   PetscBool      flag;
1336   PetscInt       two   = 2;
1337   MPI_Comm       comm;
1338 
1339   PetscFunctionBegin;
1340   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1341   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG options");CHKERRQ(ierr);
1342   {
1343     /* -pc_gamg_type */
1344     {
1345       char tname[256];
1346       ierr = PetscOptionsFList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, pc_gamg->gamg_type_name, tname, sizeof(tname), &flag);CHKERRQ(ierr);
1347       if (flag) {
1348         ierr = PCGAMGSetType(pc,tname);CHKERRQ(ierr);
1349       }
1350     }
1351     /* -pc_gamg_verbose */
1352     ierr = PetscOptionsInt("-pc_gamg_verbose","Verbose (debugging) output for PCGAMG","none", pc_gamg->verbose,&pc_gamg->verbose, NULL);CHKERRQ(ierr);
1353     /* -pc_gamg_repartition */
1354     ierr = PetscOptionsBool("-pc_gamg_repartition","Repartion coarse grids","PCGAMGRepartitioning",pc_gamg->repart,&pc_gamg->repart,NULL);CHKERRQ(ierr);
1355     /* -pc_gamg_reuse_interpolation */
1356     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation","Reuse prolongation operator","PCGAMGReuseInterpolation",pc_gamg->reuse_prol,&pc_gamg->reuse_prol,NULL);CHKERRQ(ierr);
1357     /* -pc_gamg_use_agg_gasm */
1358     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);
1359     /* -pc_gamg_process_eq_limit */
1360     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);
1361     /* -pc_gamg_coarse_eq_limit */
1362     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);
1363     /* -pc_gamg_threshold */
1364     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);
1365     if (flag && pc_gamg->verbose) {
1366       ierr = PetscPrintf(comm,"\t[%d]%s threshold set %e\n",0,__FUNCT__,pc_gamg->threshold);CHKERRQ(ierr);
1367     }
1368     /* -pc_gamg_eigtarget */
1369     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1370     ierr = PetscOptionsInt("-pc_mg_levels","Set number of MG levels","PCGAMGSetNlevels",pc_gamg->Nlevels,&pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
1371 
1372     /* set options for subtype */
1373     if (pc_gamg->ops->setfromoptions) {ierr = (*pc_gamg->ops->setfromoptions)(PetscOptionsObject,pc);CHKERRQ(ierr);}
1374   }
1375   ierr = PetscOptionsTail();CHKERRQ(ierr);
1376   PetscFunctionReturn(0);
1377 }
1378 
1379 /* -------------------------------------------------------------------------- */
1380 /*MC
1381      PCGAMG - Geometric algebraic multigrid (AMG) preconditioner
1382 
1383    Options Database Keys:
1384    Multigrid options(inherited)
1385 +  -pc_mg_cycles <v>: v or w (PCMGSetCycleType())
1386 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
1387 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
1388 -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade
1389 
1390 
1391   Notes: In order to obtain good performance for PCGAMG for vector valued problems you must
1392 $       Call MatSetBlockSize() to indicate the number of degrees of freedom per grid point
1393 $       Call MatSetNearNullSpace() (or PCSetCoordinates() if solving the equations of elasticity) to indicate the near null space of the operator
1394 $       See the Users Manual Chapter 4 for more details
1395 
1396   Level: intermediate
1397 
1398   Concepts: algebraic multigrid
1399 
1400 .seealso:  PCCreate(), PCSetType(), MatSetBlockSize(), PCMGType, PCSetCoordinates(), MatSetNearNullSpace(), PCGAMGSetType(), PCGAMGAGG, PCGAMGGEO, PCGAMGCLASSICAL, PCGAMGSetProcEqLim(),
1401            PCGAMGSetCoarseEqLim(), PCGAMGSetRepartitioning(), PCGAMGRegister(), PCGAMGSetReuseInterpolation(), PCGAMGSetUseASMAggs(), PCGAMGSetNlevels(), PCGAMGSetThreshold(), PCGAMGGetType()
1402 M*/
1403 
1404 #undef __FUNCT__
1405 #define __FUNCT__ "PCCreate_GAMG"
1406 PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
1407 {
1408   PetscErrorCode ierr;
1409   PC_GAMG        *pc_gamg;
1410   PC_MG          *mg;
1411 #if defined PETSC_GAMG_USE_LOG
1412   static long count = 0;
1413 #endif
1414 
1415   PetscFunctionBegin;
1416   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1417   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr); /* calls PCCreate_MG() and MGCreate_Private() */
1418   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1419 
1420   /* create a supporting struct and attach it to pc */
1421   ierr         = PetscNewLog(pc,&pc_gamg);CHKERRQ(ierr);
1422   mg           = (PC_MG*)pc->data;
1423   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally */
1424   mg->innerctx = pc_gamg;
1425 
1426   ierr = PetscNewLog(pc,&pc_gamg->ops);CHKERRQ(ierr);
1427 
1428   pc_gamg->setup_count = 0;
1429   /* these should be in subctx but repartitioning needs simple arrays */
1430   pc_gamg->data_sz = 0;
1431   pc_gamg->data    = 0;
1432 
1433   /* register AMG type */
1434   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1435 
1436   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
1437   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
1438   pc->ops->setup          = PCSetUp_GAMG;
1439   pc->ops->reset          = PCReset_GAMG;
1440   pc->ops->destroy        = PCDestroy_GAMG;
1441 
1442   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1443   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1444   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1445   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseInterpolation_C",PCGAMGSetReuseInterpolation_GAMG);CHKERRQ(ierr);
1446   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1447   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1448   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);CHKERRQ(ierr);
1449   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGGetType_C",PCGAMGGetType_GAMG);CHKERRQ(ierr);
1450   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);CHKERRQ(ierr);
1451   pc_gamg->repart           = PETSC_FALSE;
1452   pc_gamg->reuse_prol       = PETSC_FALSE;
1453   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
1454   pc_gamg->min_eq_proc      = 50;
1455   pc_gamg->coarse_eq_limit  = 50;
1456   pc_gamg->threshold        = 0.;
1457   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
1458   pc_gamg->verbose          = 0;
1459   pc_gamg->emax_id          = -1;
1460   pc_gamg->firstCoarsen     = PETSC_FALSE;
1461   pc_gamg->eigtarget[0]     = 0.05;
1462   pc_gamg->eigtarget[1]     = 1.05;
1463   pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
1464 
1465   /* private events */
1466 #if defined PETSC_GAMG_USE_LOG
1467   if (count++ == 0) {
1468     ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1469     ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
1470     /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
1471     /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
1472     /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
1473     ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1474     ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1475     ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1476     ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1477     ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1478     ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1479     ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1480     ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1481     ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1482     ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1483     ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1484     ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1485 
1486     /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
1487     /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
1488     /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
1489     /* create timer stages */
1490 #if defined GAMG_STAGES
1491     {
1492       char     str[32];
1493       PetscInt lidx;
1494       sprintf(str,"MG Level %d (finest)",0);
1495       ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1496       for (lidx=1; lidx<9; lidx++) {
1497         sprintf(str,"MG Level %d",lidx);
1498         ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1499       }
1500     }
1501 #endif
1502   }
1503 #endif
1504   /* PCSetUp_GAMG assumes that the type has been set, so set it to the default now */
1505   ierr = PCGAMGSetType(pc,PCGAMGAGG);CHKERRQ(ierr);
1506   PetscFunctionReturn(0);
1507 }
1508 
1509 #undef __FUNCT__
1510 #define __FUNCT__ "PCGAMGInitializePackage"
1511 /*@C
1512  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
1513  from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
1514  when using static libraries.
1515 
1516  Level: developer
1517 
1518  .keywords: PC, PCGAMG, initialize, package
1519  .seealso: PetscInitialize()
1520 @*/
1521 PetscErrorCode PCGAMGInitializePackage(void)
1522 {
1523   PetscErrorCode ierr;
1524 
1525   PetscFunctionBegin;
1526   if (PCGAMGPackageInitialized) PetscFunctionReturn(0);
1527   PCGAMGPackageInitialized = PETSC_TRUE;
1528   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);CHKERRQ(ierr);
1529   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);CHKERRQ(ierr);
1530   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGCLASSICAL,PCCreateGAMG_Classical);CHKERRQ(ierr);
1531   ierr = PetscRegisterFinalize(PCGAMGFinalizePackage);CHKERRQ(ierr);
1532 
1533   /* general events */
1534 #if defined PETSC_USE_LOG
1535   ierr = PetscLogEventRegister("PCGAMGgraph_AGG", 0, &PC_GAMGGgraph_AGG);CHKERRQ(ierr);
1536   ierr = PetscLogEventRegister("PCGAMGgraph_GEO", PC_CLASSID, &PC_GAMGGgraph_GEO);CHKERRQ(ierr);
1537   ierr = PetscLogEventRegister("PCGAMGcoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1538   ierr = PetscLogEventRegister("PCGAMGcoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1539   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1540   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1541   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptprol_AGG);CHKERRQ(ierr);
1542 #endif
1543 
1544   PetscFunctionReturn(0);
1545 }
1546 
1547 #undef __FUNCT__
1548 #define __FUNCT__ "PCGAMGFinalizePackage"
1549 /*@C
1550  PCGAMGFinalizePackage - This function destroys everything in the PCGAMG package. It is
1551  called from PetscFinalize().
1552 
1553  Level: developer
1554 
1555  .keywords: Petsc, destroy, package
1556  .seealso: PetscFinalize()
1557 @*/
1558 PetscErrorCode PCGAMGFinalizePackage(void)
1559 {
1560   PetscErrorCode ierr;
1561 
1562   PetscFunctionBegin;
1563   PCGAMGPackageInitialized = PETSC_FALSE;
1564   ierr = PetscFunctionListDestroy(&GAMGList);CHKERRQ(ierr);
1565   PetscFunctionReturn(0);
1566 }
1567 
1568 #undef __FUNCT__
1569 #define __FUNCT__ "PCGAMGRegister"
1570 /*@C
1571  PCGAMGRegister - Register a PCGAMG implementation.
1572 
1573  Input Parameters:
1574  + type - string that will be used as the name of the GAMG type.
1575  - create - function for creating the gamg context.
1576 
1577   Level: advanced
1578 
1579  .seealso: PCGAMGGetContext(), PCGAMGSetContext()
1580 @*/
1581 PetscErrorCode PCGAMGRegister(PCGAMGType type, PetscErrorCode (*create)(PC))
1582 {
1583   PetscErrorCode ierr;
1584 
1585   PetscFunctionBegin;
1586   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1587   ierr = PetscFunctionListAdd(&GAMGList,type,create);CHKERRQ(ierr);
1588   PetscFunctionReturn(0);
1589 }
1590 
1591