xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision 186d4ecdc2f8f3d4a2a0951ddba16cdc5cd22fa1)
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 
8 #if defined PETSC_GAMG_USE_LOG
9 PetscLogEvent petsc_gamg_setup_events[NUM_SET];
10 #endif
11 
12 #if defined PETSC_USE_LOG
13 PetscLogEvent PC_GAMGGgraph_AGG;
14 PetscLogEvent PC_GAMGGgraph_GEO;
15 PetscLogEvent PC_GAMGCoarsen_AGG;
16 PetscLogEvent PC_GAMGCoarsen_GEO;
17 PetscLogEvent PC_GAMGProlongator_AGG;
18 PetscLogEvent PC_GAMGProlongator_GEO;
19 PetscLogEvent PC_GAMGOptprol_AGG;
20 PetscLogEvent PC_GAMGKKTProl_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 
32 /* ----------------------------------------------------------------------------- */
33 #undef __FUNCT__
34 #define __FUNCT__ "PCReset_GAMG"
35 PetscErrorCode PCReset_GAMG(PC pc)
36 {
37   PetscErrorCode ierr;
38   PC_MG          *mg      = (PC_MG*)pc->data;
39   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
40 
41   PetscFunctionBegin;
42   if (pc_gamg->data) { /* this should not happen, cleaned up in SetUp */
43     PetscPrintf(PetscObjectComm((PetscObject)pc),"***[%d]%s this should not happen, cleaned up in SetUp\n",0,__FUNCT__);
44     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
45   }
46   pc_gamg->data = NULL; pc_gamg->data_sz = 0;
47 
48   if (pc_gamg->orig_data) {
49     ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
50   }
51   PetscFunctionReturn(0);
52 }
53 
54 /* private 2x2 Mat Nest for Stokes */
55 typedef struct {
56   Mat A11,A21,A12,Amat;
57   IS  prim_is,constr_is;
58 } GAMGKKTMat;
59 
60 #undef __FUNCT__
61 #define __FUNCT__ "GAMGKKTMatCreate"
62 static PetscErrorCode GAMGKKTMatCreate(Mat A, PetscBool iskkt, GAMGKKTMat *out)
63 {
64   PetscFunctionBegin;
65   out->Amat = A;
66   if (iskkt) {
67     PetscErrorCode ierr;
68     IS             is_constraint, is_prime;
69     PetscInt       nmin,nmax;
70 
71     ierr = MatGetOwnershipRange(A, &nmin, &nmax);CHKERRQ(ierr);
72     ierr = MatFindZeroDiagonals(A, &is_constraint);CHKERRQ(ierr);
73     ierr = ISComplement(is_constraint, nmin, nmax, &is_prime);CHKERRQ(ierr);
74 
75     out->prim_is   = is_prime;
76     out->constr_is = is_constraint;
77 
78     ierr = MatGetSubMatrix(A, is_prime, is_prime,      MAT_INITIAL_MATRIX, &out->A11);CHKERRQ(ierr);
79     ierr = MatGetSubMatrix(A, is_prime, is_constraint, MAT_INITIAL_MATRIX, &out->A12);CHKERRQ(ierr);
80     ierr = MatGetSubMatrix(A, is_constraint, is_prime, MAT_INITIAL_MATRIX, &out->A21);CHKERRQ(ierr);
81   } else {
82     out->A11       = A;
83     out->A21       = NULL;
84     out->A12       = NULL;
85     out->prim_is   = NULL;
86     out->constr_is = NULL;
87   }
88   PetscFunctionReturn(0);
89 }
90 
91 #undef __FUNCT__
92 #define __FUNCT__ "GAMGKKTMatDestroy"
93 static PetscErrorCode GAMGKKTMatDestroy(GAMGKKTMat *mat)
94 {
95   PetscErrorCode ierr;
96 
97   PetscFunctionBegin;
98   if (mat->A11 && mat->A11 != mat->Amat) {
99     ierr = MatDestroy(&mat->A11);CHKERRQ(ierr);
100   }
101   ierr = MatDestroy(&mat->A21);CHKERRQ(ierr);
102   ierr = MatDestroy(&mat->A12);CHKERRQ(ierr);
103 
104   ierr = ISDestroy(&mat->prim_is);CHKERRQ(ierr);
105   ierr = ISDestroy(&mat->constr_is);CHKERRQ(ierr);
106   PetscFunctionReturn(0);
107 }
108 
109 /* -------------------------------------------------------------------------- */
110 /*
111    createLevel: create coarse op with RAP.  repartition and/or reduce number
112      of active processors.
113 
114    Input Parameter:
115    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
116           'pc_gamg->data_sz' are changed via repartitioning/reduction.
117    . Amat_fine - matrix on this fine (k) level
118    . cr_bs - coarse block size
119    . isLast -
120    . stokes -
121    In/Output Parameter:
122    . a_P_inout - prolongation operator to the next level (k-->k-1)
123    . a_nactive_proc - number of active procs
124    Output Parameter:
125    . a_Amat_crs - coarse matrix that is created (k-1)
126 */
127 
128 #undef __FUNCT__
129 #define __FUNCT__ "createLevel"
130 static PetscErrorCode createLevel(const PC pc,const Mat Amat_fine,const PetscInt cr_bs,const PetscBool isLast,const PetscBool stokes,Mat *a_P_inout,Mat *a_Amat_crs,PetscMPIInt *a_nactive_proc)
131 {
132   PetscErrorCode  ierr;
133   PC_MG           *mg         = (PC_MG*)pc->data;
134   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
135   const PetscBool repart      = pc_gamg->repart;
136   const PetscInt  min_eq_proc = pc_gamg->min_eq_proc, coarse_max = pc_gamg->coarse_eq_limit;
137   Mat             Cmat,Pold=*a_P_inout;
138   MPI_Comm        comm;
139   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
140   PetscInt        ncrs_eq,ncrs_prim,f_bs;
141 
142   PetscFunctionBegin;
143   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
144   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
145   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
146   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
147   /* RAP */
148   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
149 
150   /* set 'ncrs_prim' (nodes), 'ncrs_eq' (equations)*/
151   ncrs_prim = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
152   if (pc_gamg->data_sz % (pc_gamg->data_cell_cols*pc_gamg->data_cell_rows)) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"pc_gamg->data_sz %D not divisible by (pc_gamg->data_cell_cols %D *pc_gamg->data_cell_rows %D)",pc_gamg->data_sz,pc_gamg->data_cell_cols,pc_gamg->data_cell_rows);
153   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
154 
155   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
156   {
157     PetscInt ncrs_eq_glob;
158     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
159     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
160     if (new_size == 0 || ncrs_eq_glob < coarse_max) new_size = 1;
161     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
162     if (isLast) new_size = 1;
163   }
164 
165   if (!repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
166   else {
167     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
168     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_prim_new,ncrs_eq_new,nloc_old;
169     IS             is_eq_newproc,is_eq_newproc_prim,is_eq_num,is_eq_num_prim,isscat,new_eq_indices;
170     VecScatter     vecscat;
171     PetscScalar    *array;
172     Vec            src_crd, dest_crd;
173 
174     nloc_old = ncrs_eq/cr_bs;
175     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);
176 #if defined PETSC_GAMG_USE_LOG
177     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
178 #endif
179     /* make 'is_eq_newproc' */
180     ierr = PetscMalloc(size*sizeof(PetscInt), &counts);CHKERRQ(ierr);
181     if (repart && !stokes) {
182       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
183       Mat adj;
184 
185       if (pc_gamg->verbose>0) {
186         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);
187         else {
188           PetscInt n;
189           ierr = MPI_Allreduce(&ncrs_eq, &n, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
190           PetscPrintf(comm,"\t[%d]%s repartition: size (active): %d --> %d, neq = %d\n",rank,__FUNCT__,*a_nactive_proc,new_size,n);
191         }
192       }
193 
194       /* get 'adj' */
195       if (cr_bs == 1) {
196         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
197       } else {
198         /* make a scalar matrix to partition (no Stokes here) */
199         Mat               tMat;
200         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
201         const PetscScalar *vals;
202         const PetscInt    *idx;
203         PetscInt          *d_nnz, *o_nnz, M, N;
204         static PetscInt   llev = 0;
205 
206         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &d_nnz);CHKERRQ(ierr);
207         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &o_nnz);CHKERRQ(ierr);
208         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
209         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
210         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
211           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
212           d_nnz[jj] = ncols/cr_bs;
213           o_nnz[jj] = ncols/cr_bs;
214           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
215           if (d_nnz[jj] > ncrs_prim) d_nnz[jj] = ncrs_prim;
216           if (o_nnz[jj] > (M/cr_bs-ncrs_prim)) o_nnz[jj] = M/cr_bs-ncrs_prim;
217         }
218 
219         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
220         ierr = MatSetSizes(tMat, ncrs_prim, ncrs_prim,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
221         ierr = MatSetType(tMat,MATAIJ);CHKERRQ(ierr);
222         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
223         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
224         ierr = PetscFree(d_nnz);CHKERRQ(ierr);
225         ierr = PetscFree(o_nnz);CHKERRQ(ierr);
226 
227         for (ii = Istart_crs; ii < Iend_crs; ii++) {
228           PetscInt dest_row = ii/cr_bs;
229           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
230           for (jj = 0; jj < ncols; jj++) {
231             PetscInt    dest_col = idx[jj]/cr_bs;
232             PetscScalar v        = 1.0;
233             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
234           }
235           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
236         }
237         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
238         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
239 
240         if (llev++ == -1) {
241           PetscViewer viewer; char fname[32];
242           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
243           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
244           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
245           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
246         }
247 
248         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
249 
250         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
251       } /* create 'adj' */
252 
253       { /* partition: get newproc_idx */
254         char            prefix[256];
255         const char      *pcpre;
256         const PetscInt  *is_idx;
257         MatPartitioning mpart;
258         IS              proc_is;
259         PetscInt        targetPE;
260 
261         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
262         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
263         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
264         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
265         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
266         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
267         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
268         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
269         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
270 
271         /* collect IS info */
272         ierr     = PetscMalloc(ncrs_eq*sizeof(PetscInt), &newproc_idx);CHKERRQ(ierr);
273         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
274         targetPE = 1; /* bring to "front" of machine */
275         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
276         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
277           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
278             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
279           }
280         }
281         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
282         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
283       }
284       ierr = MatDestroy(&adj);CHKERRQ(ierr);
285 
286       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
287       if (newproc_idx != 0) {
288         ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
289       }
290     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
291 
292       PetscInt rfactor,targetPE;
293       /* find factor */
294       if (new_size == 1) rfactor = size; /* easy */
295       else {
296         PetscReal best_fact = 0.;
297         jj = -1;
298         for (kk = 1 ; kk <= size ; kk++) {
299           if (size%kk==0) { /* a candidate */
300             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
301             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
302             if (fact > best_fact) {
303               best_fact = fact; jj = kk;
304             }
305           }
306         }
307         if (jj != -1) rfactor = jj;
308         else rfactor = 1; /* does this happen .. a prime */
309       }
310       new_size = size/rfactor;
311 
312       if (new_size==nactive) {
313         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
314         ierr        = PetscFree(counts);CHKERRQ(ierr);
315         if (pc_gamg->verbose>0) {
316           PetscPrintf(comm,"\t[%d]%s aggregate processors noop: new_size=%d, neq(loc)=%d\n",rank,__FUNCT__,new_size,ncrs_eq);
317         }
318         PetscFunctionReturn(0);
319       }
320 
321       if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s number of equations (loc) %d with simple aggregation\n",rank,__FUNCT__,ncrs_eq);
322       targetPE = rank/rfactor;
323       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
324 
325       if (stokes) {
326         ierr = ISCreateStride(comm, ncrs_prim*cr_bs, targetPE, 0, &is_eq_newproc_prim);CHKERRQ(ierr);
327       }
328     } /* end simple 'is_eq_newproc' */
329 
330     /*
331      Create an index set from the is_eq_newproc index set to indicate the mapping TO
332      */
333     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
334     if (stokes) {
335       ierr = ISPartitioningToNumbering(is_eq_newproc_prim, &is_eq_num_prim);CHKERRQ(ierr);
336     } else is_eq_num_prim = is_eq_num;
337     /*
338       Determine how many equations/vertices are assigned to each processor
339      */
340     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
341     ncrs_eq_new = counts[rank];
342     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
343     if (stokes) {
344       ierr          = ISPartitioningCount(is_eq_newproc_prim, size, counts);CHKERRQ(ierr);
345       ierr          = ISDestroy(&is_eq_newproc_prim);CHKERRQ(ierr);
346       ncrs_prim_new = counts[rank]/cr_bs; /* nodes */
347     } else ncrs_prim_new = ncrs_eq_new/cr_bs; /* eqs */
348 
349     ierr = PetscFree(counts);CHKERRQ(ierr);
350 #if defined PETSC_GAMG_USE_LOG
351     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
352 #endif
353 
354     /* move data (for primal equations only) */
355     /* Create a vector to contain the newly ordered element information */
356     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
357     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_prim_new, PETSC_DECIDE);CHKERRQ(ierr);
358     ierr = VecSetFromOptions(dest_crd);CHKERRQ(ierr); /* this is needed! */
359     /*
360      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
361      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
362      */
363     ierr = PetscMalloc((ncrs_prim*node_data_sz)*sizeof(PetscInt), &tidx);CHKERRQ(ierr);
364     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
365     for (ii=0,jj=0; ii<ncrs_prim; ii++) {
366       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
367       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
368     }
369     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
370     ierr = ISCreateGeneral(comm, node_data_sz*ncrs_prim, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
371     ierr = PetscFree(tidx);CHKERRQ(ierr);
372     /*
373      Create a vector to contain the original vertex information for each element
374      */
375     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs_prim, &src_crd);CHKERRQ(ierr);
376     for (jj=0; jj<ndata_cols; jj++) {
377       const PetscInt stride0=ncrs_prim*pc_gamg->data_cell_rows;
378       for (ii=0; ii<ncrs_prim; ii++) {
379         for (kk=0; kk<ndata_rows; kk++) {
380           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
381           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
382           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
383         }
384       }
385     }
386     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
387     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
388     /*
389       Scatter the element vertex information (still in the original vertex ordering)
390       to the correct processor
391     */
392     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
393     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
394     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
395     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
396     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
397     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
398     /*
399       Put the element vertex data into a new allocation of the gdata->ele
400     */
401     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
402     ierr = PetscMalloc(node_data_sz*ncrs_prim_new*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
403 
404     pc_gamg->data_sz = node_data_sz*ncrs_prim_new;
405     strideNew        = ncrs_prim_new*ndata_rows;
406 
407     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
408     for (jj=0; jj<ndata_cols; jj++) {
409       for (ii=0; ii<ncrs_prim_new; ii++) {
410         for (kk=0; kk<ndata_rows; kk++) {
411           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
412           pc_gamg->data[ix] = PetscRealPart(array[jx]);
413         }
414       }
415     }
416     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
417     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
418 
419     /* move A and P (columns) with new layout */
420 #if defined PETSC_GAMG_USE_LOG
421     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
422 #endif
423 
424     /*
425       Invert for MatGetSubMatrix
426     */
427     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
428     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
429     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
430     if (is_eq_num != is_eq_num_prim) {
431       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
432     }
433     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
434 #if defined PETSC_GAMG_USE_LOG
435     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
436     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
437 #endif
438     /* 'a_Amat_crs' output */
439     {
440       Mat mat;
441       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
442       *a_Amat_crs = mat;
443 
444       if (!PETSC_TRUE) {
445         PetscInt cbs, rbs;
446         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
447         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
448         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
449         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);
450       }
451     }
452     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
453 
454 #if defined PETSC_GAMG_USE_LOG
455     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
456 #endif
457     /* prolongator */
458     {
459       IS       findices;
460       PetscInt Istart,Iend;
461       Mat      Pnew;
462       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
463 #if defined PETSC_GAMG_USE_LOG
464       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
465 #endif
466       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
467       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
468       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
469       ierr = ISDestroy(&findices);CHKERRQ(ierr);
470 
471       if (!PETSC_TRUE) {
472         PetscInt cbs, rbs;
473         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
474         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
475         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
476         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
477       }
478 #if defined PETSC_GAMG_USE_LOG
479       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
480 #endif
481       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
482 
483       /* output - repartitioned */
484       *a_P_inout = Pnew;
485     }
486     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
487 
488     *a_nactive_proc = new_size; /* output */
489   }
490 
491   /* outout matrix data */
492   if (!PETSC_TRUE) {
493     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
494     if (llev==0) {
495       sprintf(fname,"Cmat_%d.m",llev++);
496       PetscViewerASCIIOpen(comm,fname,&viewer);
497       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
498       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
499       ierr = PetscViewerDestroy(&viewer);
500     }
501     sprintf(fname,"Cmat_%d.m",llev++);
502     PetscViewerASCIIOpen(comm,fname,&viewer);
503     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
504     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
505     ierr = PetscViewerDestroy(&viewer);
506   }
507   PetscFunctionReturn(0);
508 }
509 
510 /* -------------------------------------------------------------------------- */
511 /*
512    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
513                     by setting data structures and options.
514 
515    Input Parameter:
516 .  pc - the preconditioner context
517 
518    Application Interface Routine: PCSetUp()
519 
520    Notes:
521    The interface routine PCSetUp() is not usually called directly by
522    the user, but instead is called by PCApply() if necessary.
523 */
524 #undef __FUNCT__
525 #define __FUNCT__ "PCSetUp_GAMG"
526 PetscErrorCode PCSetUp_GAMG(PC pc)
527 {
528   PetscErrorCode ierr;
529   PC_MG          *mg      = (PC_MG*)pc->data;
530   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
531   Mat            Pmat     = pc->pmat;
532   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
533   MPI_Comm       comm;
534   PetscMPIInt    rank,size,nactivepe;
535   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
536   PetscReal      emaxs[GAMG_MAXLEVELS];
537   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
538   GAMGKKTMat     kktMatsArr[GAMG_MAXLEVELS];
539   PetscLogDouble nnz0=0.,nnztot=0.;
540   MatInfo        info;
541   PetscBool      stokes = PETSC_FALSE, redo_mesh_setup = (PetscBool)(!pc_gamg->reuse_prol);
542 
543   PetscFunctionBegin;
544   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
545   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
546   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
547 
548   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);
549 
550   if (pc_gamg->setup_count++ > 0) {
551     if (redo_mesh_setup) {
552       /* reset everything */
553       ierr            = PCReset_MG(pc);CHKERRQ(ierr);
554       pc->setupcalled = 0;
555     } else {
556       PC_MG_Levels **mglevels = mg->levels;
557       /* just do Galerkin grids */
558       Mat          B,dA,dB;
559 
560      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
561       if (pc_gamg->Nlevels > 1) {
562         /* currently only handle case where mat and pmat are the same on coarser levels */
563         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB,NULL);CHKERRQ(ierr);
564         /* (re)set to get dirty flag */
565         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
566 
567         for (level=pc_gamg->Nlevels-2; level>-1; level--) {
568           /* the first time through the matrix structure has changed from repartitioning */
569           if (pc_gamg->setup_count==2 /*&& (pc_gamg->repart || level==0)*/) {
570             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
571             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
572 
573             mglevels[level]->A = B;
574           } else {
575             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B,NULL);CHKERRQ(ierr);
576             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
577           }
578           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
579           dB   = B;
580         }
581       }
582 
583       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
584 
585       /* PCSetUp_MG seems to insists on setting this to GMRES */
586       ierr = KSPSetType(mglevels[0]->smoothd, KSPPREONLY);CHKERRQ(ierr);
587       PetscFunctionReturn(0);
588     }
589   }
590 
591   ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr);
592 
593   ierr = GAMGKKTMatCreate(Pmat, stokes, &kktMatsArr[0]);CHKERRQ(ierr);
594 
595   if (!pc_gamg->data) {
596     if (pc_gamg->orig_data) {
597       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
598       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
599 
600       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
601       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
602       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;
603 
604       ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
605       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
606     } else {
607       if (!pc_gamg->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
608       if (stokes) SETERRQ(comm,PETSC_ERR_PLIB,"Need data (eg, PCSetCoordinates) for Stokes problems");
609       ierr = pc_gamg->createdefaultdata(pc, kktMatsArr[0].A11);CHKERRQ(ierr);
610     }
611   }
612 
613   /* cache original data for reuse */
614   if (!pc_gamg->orig_data && redo_mesh_setup) {
615     ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->orig_data);CHKERRQ(ierr);
616     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
617     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
618     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
619   }
620 
621   /* get basic dims */
622   if (stokes) bs = pc_gamg->data_cell_rows; /* this is agg-mg specific */
623   else {
624     ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
625   }
626 
627   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
628   if (pc_gamg->verbose) {
629     PetscInt NN = M;
630     if (pc_gamg->verbose==1) {
631       ierr =  MatGetInfo(Pmat,MAT_LOCAL,&info);CHKERRQ(ierr);
632       ierr = MatGetLocalSize(Pmat, &NN, &qq);CHKERRQ(ierr);
633     } else {
634       ierr = MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr);
635     }
636     nnz0   = info.nz_used;
637     nnztot = info.nz_used;
638     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",
639                          rank,__FUNCT__,0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
640                          (int)(nnz0/(PetscReal)NN),size);CHKERRQ(ierr);
641   }
642 
643   /* Get A_i and R_i */
644   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
645        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);  /* && (size==1 || nactivepe>1); */
646        level++) {
647     level1 = level + 1;
648 #if defined PETSC_GAMG_USE_LOG
649     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
650 #if (defined GAMG_STAGES)
651     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
652 #endif
653 #endif
654     /* deal with Stokes, get sub matrices */
655     if (level > 0) {
656       ierr = GAMGKKTMatCreate(Aarr[level], stokes, &kktMatsArr[level]);CHKERRQ(ierr);
657     }
658     { /* construct prolongator */
659       Mat              Gmat;
660       PetscCoarsenData *agg_lists;
661       Mat              Prol11,Prol22;
662 
663       ierr = pc_gamg->graph(pc,kktMatsArr[level].A11, &Gmat);CHKERRQ(ierr);
664       ierr = pc_gamg->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
665       ierr = pc_gamg->prolongator(pc, kktMatsArr[level].A11, Gmat, agg_lists, &Prol11);CHKERRQ(ierr);
666 
667       /* could have failed to create new level */
668       if (Prol11) {
669         /* get new block size of coarse matrices */
670         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
671 
672         if (stokes) {
673           if (!pc_gamg->formkktprol) SETERRQ(comm,PETSC_ERR_USER,"Stokes not supportd by AMG method.");
674           /* R A12 == (T = A21 P)';  G = T' T; coarsen G; form plain agg with G */
675           ierr = pc_gamg->formkktprol(pc, Prol11, kktMatsArr[level].A21, &Prol22);CHKERRQ(ierr);
676         }
677 
678         if (pc_gamg->optprol) {
679           /* smooth */
680           ierr = pc_gamg->optprol(pc, kktMatsArr[level].A11, &Prol11);CHKERRQ(ierr);
681         }
682 
683         if (stokes) {
684           IS  is_row[2];
685           Mat a[4];
686 
687           is_row[0] = kktMatsArr[level].prim_is; is_row[1] = kktMatsArr[level].constr_is;
688           a[0]      = Prol11; a[1] = NULL; a[2] = NULL; a[3] = Prol22;
689           ierr      = MatCreateNest(comm,2,is_row, 2, is_row, a, &Parr[level1]);CHKERRQ(ierr);
690         } else Parr[level1] = Prol11;
691       } else Parr[level1] = NULL;
692 
693       if (pc_gamg->use_aggs_in_gasm) {
694         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
695       }
696 
697       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
698       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
699     } /* construct prolongator scope */
700 #if defined PETSC_GAMG_USE_LOG
701     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
702 #endif
703     /* cache eigen estimate */
704     if (pc_gamg->emax_id != -1) {
705       PetscBool flag;
706       ierr = PetscObjectComposedDataGetReal((PetscObject)kktMatsArr[level].A11, pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
707       if (!flag) emaxs[level] = -1.;
708     } else emaxs[level] = -1.;
709     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
710     if (!Parr[level1]) {
711       if (pc_gamg->verbose) {
712         ierr =  PetscPrintf(comm,"\t[%d]%s stop gridding, level %d\n",rank,__FUNCT__,level);CHKERRQ(ierr);
713       }
714       break;
715     }
716 #if defined PETSC_GAMG_USE_LOG
717     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
718 #endif
719 
720     ierr = createLevel(pc, Aarr[level], bs, (PetscBool)(level==pc_gamg->Nlevels-2),
721                        stokes, &Parr[level1], &Aarr[level1], &nactivepe);CHKERRQ(ierr);
722 
723 #if defined PETSC_GAMG_USE_LOG
724     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
725 #endif
726     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
727 
728     if (pc_gamg->verbose > 0) {
729       PetscInt NN = M;
730       if (pc_gamg->verbose==1) {
731         ierr = MatGetInfo(Aarr[level1],MAT_LOCAL,&info);CHKERRQ(ierr);
732         ierr = MatGetLocalSize(Aarr[level1], &NN, &qq);CHKERRQ(ierr);
733       } else {
734         ierr = MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
735       }
736 
737       nnztot += info.nz_used;
738       ierr    = PetscPrintf(comm,"\t\t[%d]%s %d) N=%d, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",
739                             rank,__FUNCT__,(int)level1,M,pc_gamg->data_cell_cols,
740                             (int)(info.nz_used/(PetscReal)NN), nactivepe);CHKERRQ(ierr);
741     }
742 
743     /* stop if one node -- could pull back for singular problems */
744     if (M/pc_gamg->data_cell_cols < 2) {
745       level++;
746       break;
747     }
748 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
749     ierr = PetscLogStagePop();CHKERRQ(ierr);
750 #endif
751   } /* levels */
752 
753   if (pc_gamg->data) {
754     ierr          = PetscFree(pc_gamg->data);CHKERRQ(ierr);
755     pc_gamg->data = NULL;
756   }
757 
758   if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s %d levels, grid complexity = %g\n",0,__FUNCT__,level+1,nnztot/nnz0);
759   pc_gamg->Nlevels = level + 1;
760   fine_level       = level;
761   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
762 
763   /* simple setup */
764   if (!PETSC_TRUE) {
765     PC_MG_Levels **mglevels = mg->levels;
766     for (lidx=0,level=pc_gamg->Nlevels-1;
767          lidx<fine_level;
768          lidx++, level--) {
769       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
770       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
771       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
772       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
773     }
774     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
775 
776     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
777   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
778     /* set default smoothers & set operators */
779     for (lidx = 1, level = pc_gamg->Nlevels-2;
780          lidx <= fine_level;
781          lidx++, level--) {
782       KSP smoother;
783       PC  subpc;
784 
785       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
786       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
787 
788       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
789       /* set ops */
790       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
791       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
792 
793       /* create field split PC, get subsmoother */
794       if (stokes) {
795         KSP      *ksps;
796         PetscInt nn;
797         ierr     = PCFieldSplitSetIS(subpc,"0",kktMatsArr[level].prim_is);CHKERRQ(ierr);
798         ierr     = PCFieldSplitSetIS(subpc,"1",kktMatsArr[level].constr_is);CHKERRQ(ierr);
799         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
800         smoother = ksps[0];
801         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
802         ierr     = PetscFree(ksps);CHKERRQ(ierr);
803       }
804       ierr = GAMGKKTMatDestroy(&kktMatsArr[level]);CHKERRQ(ierr);
805 
806       /* set defaults */
807       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
808 
809       /* override defaults and command line args (!) */
810       if (pc_gamg->use_aggs_in_gasm) {
811         PetscInt sz;
812         IS       *is;
813 
814         sz   = nASMBlocksArr[level];
815         is   = ASMLocalIDsArr[level];
816         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
817         if (sz==0) {
818           IS       is;
819           PetscInt my0,kk;
820           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
821           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
822           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
823           ierr = ISDestroy(&is);CHKERRQ(ierr);
824         } else {
825           PetscInt kk;
826           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
827           for (kk=0; kk<sz; kk++) {
828             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
829           }
830           ierr = PetscFree(is);CHKERRQ(ierr);
831         }
832         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
833 
834         ASMLocalIDsArr[level] = NULL;
835         nASMBlocksArr[level]  = 0;
836         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
837       } else {
838         ierr = PCSetType(subpc, PCJACOBI);CHKERRQ(ierr);
839       }
840     }
841     {
842       /* coarse grid */
843       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
844       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
845       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
846       ierr = KSPSetOperators(smoother, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
847       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
848       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
849       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
850       ierr = PCSetUp(subpc);CHKERRQ(ierr);
851       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
852       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
853       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
854       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
855       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
856     }
857 
858     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
859     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
860     ierr = PCSetFromOptions_MG(pc);CHKERRQ(ierr);
861     ierr = PetscOptionsEnd();CHKERRQ(ierr);
862     if (mg->galerkin != 2) SETERRQ(comm,PETSC_ERR_USER,"GAMG does Galerkin manually so the -pc_mg_galerkin option must not be used.");
863 
864     /* create cheby smoothers */
865     for (lidx = 1, level = pc_gamg->Nlevels-2;
866          lidx <= fine_level;
867          lidx++, level--) {
868       KSP       smoother;
869       PetscBool flag;
870       PC        subpc;
871 
872       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
873       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
874 
875       /* create field split PC, get subsmoother */
876       if (stokes) {
877         KSP      *ksps;
878         PetscInt nn;
879         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
880         smoother = ksps[0];
881         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
882         ierr     = PetscFree(ksps);CHKERRQ(ierr);
883       }
884 
885       /* do my own cheby */
886       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
887       if (flag) {
888         PetscReal emax, emin;
889         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
890         if (flag && emaxs[level] > 0.0) emax=emaxs[level]; /* eigen estimate only for diagnal PC */
891         else { /* eigen estimate 'emax' */
892           KSP eksp;
893           Mat Lmat = Aarr[level];
894           Vec bb, xx;
895 
896           ierr = MatGetVecs(Lmat, &bb, 0);CHKERRQ(ierr);
897           ierr = MatGetVecs(Lmat, &xx, 0);CHKERRQ(ierr);
898           {
899             PetscRandom rctx;
900             ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
901             ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
902             ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
903             ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
904           }
905 
906           /* zeroing out BC rows -- needed for crazy matrices */
907           {
908             PetscInt    Istart,Iend,ncols,jj,Ii;
909             PetscScalar zero = 0.0;
910             ierr = MatGetOwnershipRange(Lmat, &Istart, &Iend);CHKERRQ(ierr);
911             for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
912               ierr = MatGetRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
913               if (ncols <= 1) {
914                 ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
915               }
916               ierr = MatRestoreRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
917             }
918             ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
919             ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
920           }
921 
922           ierr = KSPCreate(comm, &eksp);CHKERRQ(ierr);
923           ierr = KSPSetTolerances(eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10);CHKERRQ(ierr);
924           ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
925           ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
926           ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
927           ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
928 
929           ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
930           ierr = KSPSetOperators(eksp, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
931           ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
932 
933           /* set PC type to be same as smoother */
934           ierr = KSPSetPC(eksp, subpc);CHKERRQ(ierr);
935 
936           /* solve - keep stuff out of logging */
937           ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
938           ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
939           ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
940           ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
941           ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
942 
943           ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
944 
945           ierr = VecDestroy(&xx);CHKERRQ(ierr);
946           ierr = VecDestroy(&bb);CHKERRQ(ierr);
947           ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
948 
949           if (pc_gamg->verbose > 0) {
950             PetscInt N1, tt;
951             ierr = MatGetSize(Aarr[level], &N1, &tt);CHKERRQ(ierr);
952             PetscPrintf(comm,"\t\t\t%s PC setup max eigen=%e min=%e on level %d (N=%d)\n",__FUNCT__,emax,emin,lidx,N1);
953           }
954         }
955         {
956           PetscInt N1, N0;
957           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
958           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
959           /* heuristic - is this crap? */
960           /* emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); */
961           emin  = emax * pc_gamg->eigtarget[0];
962           emax *= pc_gamg->eigtarget[1];
963         }
964         ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
965       } /* setup checby flag */
966     } /* non-coarse levels */
967 
968     /* clean up */
969     for (level=1; level<pc_gamg->Nlevels; level++) {
970       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
971       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
972     }
973 
974     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
975 
976     if (PETSC_TRUE) {
977       KSP smoother;  /* PCSetUp_MG seems to insists on setting this to GMRES on coarse grid */
978       ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
979       ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
980     }
981   } else {
982     KSP smoother;
983     if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s one level solver used (system is seen as DD). Using default solver.\n",rank,__FUNCT__);
984     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
985     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
986     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
987     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
988   }
989   PetscFunctionReturn(0);
990 }
991 
992 /* ------------------------------------------------------------------------- */
993 /*
994  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
995    that was created with PCCreate_GAMG().
996 
997    Input Parameter:
998 .  pc - the preconditioner context
999 
1000    Application Interface Routine: PCDestroy()
1001 */
1002 #undef __FUNCT__
1003 #define __FUNCT__ "PCDestroy_GAMG"
1004 PetscErrorCode PCDestroy_GAMG(PC pc)
1005 {
1006   PetscErrorCode ierr;
1007   PC_MG          *mg     = (PC_MG*)pc->data;
1008   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
1009 
1010   PetscFunctionBegin;
1011   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
1012   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
1013   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
1014   PetscFunctionReturn(0);
1015 }
1016 
1017 
1018 #undef __FUNCT__
1019 #define __FUNCT__ "PCGAMGSetProcEqLim"
1020 /*@
1021    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via
1022    processor reduction.
1023 
1024    Not Collective on PC
1025 
1026    Input Parameters:
1027 .  pc - the preconditioner context
1028 
1029 
1030    Options Database Key:
1031 .  -pc_gamg_process_eq_limit
1032 
1033    Level: intermediate
1034 
1035    Concepts: Unstructured multrigrid preconditioner
1036 
1037 .seealso: ()
1038 @*/
1039 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
1040 {
1041   PetscErrorCode ierr;
1042 
1043   PetscFunctionBegin;
1044   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1045   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1046   PetscFunctionReturn(0);
1047 }
1048 
1049 EXTERN_C_BEGIN
1050 #undef __FUNCT__
1051 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
1052 PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
1053 {
1054   PC_MG   *mg      = (PC_MG*)pc->data;
1055   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1056 
1057   PetscFunctionBegin;
1058   if (n>0) pc_gamg->min_eq_proc = n;
1059   PetscFunctionReturn(0);
1060 }
1061 EXTERN_C_END
1062 
1063 #undef __FUNCT__
1064 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
1065 /*@
1066    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
1067 
1068  Collective on PC
1069 
1070    Input Parameters:
1071 .  pc - the preconditioner context
1072 
1073 
1074    Options Database Key:
1075 .  -pc_gamg_coarse_eq_limit
1076 
1077    Level: intermediate
1078 
1079    Concepts: Unstructured multrigrid preconditioner
1080 
1081 .seealso: ()
1082  @*/
1083 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
1084 {
1085   PetscErrorCode ierr;
1086 
1087   PetscFunctionBegin;
1088   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1089   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1090   PetscFunctionReturn(0);
1091 }
1092 
1093 EXTERN_C_BEGIN
1094 #undef __FUNCT__
1095 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
1096 PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
1097 {
1098   PC_MG   *mg      = (PC_MG*)pc->data;
1099   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1100 
1101   PetscFunctionBegin;
1102   if (n>0) pc_gamg->coarse_eq_limit = n;
1103   PetscFunctionReturn(0);
1104 }
1105 EXTERN_C_END
1106 
1107 #undef __FUNCT__
1108 #define __FUNCT__ "PCGAMGSetRepartitioning"
1109 /*@
1110    PCGAMGSetRepartitioning - Repartition the coarse grids
1111 
1112    Collective on PC
1113 
1114    Input Parameters:
1115 .  pc - the preconditioner context
1116 
1117 
1118    Options Database Key:
1119 .  -pc_gamg_repartition
1120 
1121    Level: intermediate
1122 
1123    Concepts: Unstructured multrigrid preconditioner
1124 
1125 .seealso: ()
1126 @*/
1127 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
1128 {
1129   PetscErrorCode ierr;
1130 
1131   PetscFunctionBegin;
1132   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1133   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1134   PetscFunctionReturn(0);
1135 }
1136 
1137 EXTERN_C_BEGIN
1138 #undef __FUNCT__
1139 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
1140 PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
1141 {
1142   PC_MG   *mg      = (PC_MG*)pc->data;
1143   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1144 
1145   PetscFunctionBegin;
1146   pc_gamg->repart = n;
1147   PetscFunctionReturn(0);
1148 }
1149 EXTERN_C_END
1150 
1151 #undef __FUNCT__
1152 #define __FUNCT__ "PCGAMGSetReuseProl"
1153 /*@
1154    PCGAMGSetReuseProl - Reuse prlongation
1155 
1156    Collective on PC
1157 
1158    Input Parameters:
1159 .  pc - the preconditioner context
1160 
1161 
1162    Options Database Key:
1163 .  -pc_gamg_reuse_interpolation
1164 
1165    Level: intermediate
1166 
1167    Concepts: Unstructured multrigrid preconditioner
1168 
1169 .seealso: ()
1170 @*/
1171 PetscErrorCode PCGAMGSetReuseProl(PC pc, PetscBool n)
1172 {
1173   PetscErrorCode ierr;
1174 
1175   PetscFunctionBegin;
1176   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1177   ierr = PetscTryMethod(pc,"PCGAMGSetReuseProl_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1178   PetscFunctionReturn(0);
1179 }
1180 
1181 EXTERN_C_BEGIN
1182 #undef __FUNCT__
1183 #define __FUNCT__ "PCGAMGSetReuseProl_GAMG"
1184 PetscErrorCode PCGAMGSetReuseProl_GAMG(PC pc, PetscBool n)
1185 {
1186   PC_MG   *mg      = (PC_MG*)pc->data;
1187   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1188 
1189   PetscFunctionBegin;
1190   pc_gamg->reuse_prol = n;
1191   PetscFunctionReturn(0);
1192 }
1193 EXTERN_C_END
1194 
1195 #undef __FUNCT__
1196 #define __FUNCT__ "PCGAMGSetUseASMAggs"
1197 /*@
1198    PCGAMGSetUseASMAggs -
1199 
1200    Collective on PC
1201 
1202    Input Parameters:
1203 .  pc - the preconditioner context
1204 
1205 
1206    Options Database Key:
1207 .  -pc_gamg_use_agg_gasm
1208 
1209    Level: intermediate
1210 
1211    Concepts: Unstructured multrigrid preconditioner
1212 
1213 .seealso: ()
1214 @*/
1215 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1216 {
1217   PetscErrorCode ierr;
1218 
1219   PetscFunctionBegin;
1220   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1221   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1222   PetscFunctionReturn(0);
1223 }
1224 
1225 EXTERN_C_BEGIN
1226 #undef __FUNCT__
1227 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
1228 PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
1229 {
1230   PC_MG   *mg      = (PC_MG*)pc->data;
1231   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1232 
1233   PetscFunctionBegin;
1234   pc_gamg->use_aggs_in_gasm = n;
1235   PetscFunctionReturn(0);
1236 }
1237 EXTERN_C_END
1238 
1239 #undef __FUNCT__
1240 #define __FUNCT__ "PCGAMGSetNlevels"
1241 /*@
1242    PCGAMGSetNlevels -
1243 
1244    Not collective on PC
1245 
1246    Input Parameters:
1247 .  pc - the preconditioner context
1248 
1249 
1250    Options Database Key:
1251 .  -pc_mg_levels
1252 
1253    Level: intermediate
1254 
1255    Concepts: Unstructured multrigrid preconditioner
1256 
1257 .seealso: ()
1258 @*/
1259 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1260 {
1261   PetscErrorCode ierr;
1262 
1263   PetscFunctionBegin;
1264   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1265   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1266   PetscFunctionReturn(0);
1267 }
1268 
1269 EXTERN_C_BEGIN
1270 #undef __FUNCT__
1271 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
1272 PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
1273 {
1274   PC_MG   *mg      = (PC_MG*)pc->data;
1275   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1276 
1277   PetscFunctionBegin;
1278   pc_gamg->Nlevels = n;
1279   PetscFunctionReturn(0);
1280 }
1281 EXTERN_C_END
1282 
1283 #undef __FUNCT__
1284 #define __FUNCT__ "PCGAMGSetThreshold"
1285 /*@
1286    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph
1287 
1288    Not collective on PC
1289 
1290    Input Parameters:
1291 .  pc - the preconditioner context
1292 
1293 
1294    Options Database Key:
1295 .  -pc_gamg_threshold
1296 
1297    Level: intermediate
1298 
1299    Concepts: Unstructured multrigrid preconditioner
1300 
1301 .seealso: ()
1302 @*/
1303 PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
1304 {
1305   PetscErrorCode ierr;
1306 
1307   PetscFunctionBegin;
1308   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1309   ierr = PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));CHKERRQ(ierr);
1310   PetscFunctionReturn(0);
1311 }
1312 
1313 EXTERN_C_BEGIN
1314 #undef __FUNCT__
1315 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
1316 PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
1317 {
1318   PC_MG   *mg      = (PC_MG*)pc->data;
1319   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1320 
1321   PetscFunctionBegin;
1322   pc_gamg->threshold = n;
1323   PetscFunctionReturn(0);
1324 }
1325 EXTERN_C_END
1326 
1327 #undef __FUNCT__
1328 #define __FUNCT__ "PCGAMGSetType"
1329 /*@
1330    PCGAMGSetType - Set solution method - calls sub create method
1331 
1332    Collective on PC
1333 
1334    Input Parameters:
1335 .  pc - the preconditioner context
1336 
1337 
1338    Options Database Key:
1339 .  -pc_gamg_type
1340 
1341    Level: intermediate
1342 
1343    Concepts: Unstructured multrigrid preconditioner
1344 
1345 .seealso: ()
1346 @*/
1347 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1348 {
1349   PetscErrorCode ierr;
1350 
1351   PetscFunctionBegin;
1352   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1353   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1354   PetscFunctionReturn(0);
1355 }
1356 
1357 EXTERN_C_BEGIN
1358 #undef __FUNCT__
1359 #define __FUNCT__ "PCGAMGSetType_GAMG"
1360 PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
1361 {
1362   PetscErrorCode ierr,(*r)(PC);
1363 
1364   PetscFunctionBegin;
1365   ierr = PetscFunctionListFind(PetscObjectComm((PetscObject)pc),GAMGList,type,PETSC_FALSE,(PetscVoidStarFunction)&r);CHKERRQ(ierr);
1366   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
1367   ierr = (*r)(pc);CHKERRQ(ierr);
1368   PetscFunctionReturn(0);
1369 }
1370 EXTERN_C_END
1371 
1372 #undef __FUNCT__
1373 #define __FUNCT__ "PCSetFromOptions_GAMG"
1374 PetscErrorCode PCSetFromOptions_GAMG(PC pc)
1375 {
1376   PetscErrorCode ierr;
1377   PC_MG          *mg      = (PC_MG*)pc->data;
1378   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1379   PetscBool      flag;
1380   PetscInt       two   = 2;
1381   MPI_Comm       comm;
1382 
1383   PetscFunctionBegin;
1384   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1385   ierr = PetscOptionsHead("GAMG options");CHKERRQ(ierr);
1386   {
1387     /* -pc_gamg_verbose */
1388     ierr = PetscOptionsInt("-pc_gamg_verbose","Verbose (debugging) output for PCGAMG",
1389                            "none", pc_gamg->verbose,
1390                            &pc_gamg->verbose, NULL);CHKERRQ(ierr);
1391     /* -pc_gamg_repartition */
1392     ierr = PetscOptionsBool("-pc_gamg_repartition",
1393                             "Repartion coarse grids (false)",
1394                             "PCGAMGRepartitioning",
1395                             pc_gamg->repart,
1396                             &pc_gamg->repart,
1397                             &flag);CHKERRQ(ierr);
1398     /* -pc_gamg_reuse_interpolation */
1399     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation",
1400                             "Reuse prolongation operator (true)",
1401                             "PCGAMGReuseProl",
1402                             pc_gamg->reuse_prol,
1403                             &pc_gamg->reuse_prol,
1404                             &flag);CHKERRQ(ierr);
1405     /* -pc_gamg_use_agg_gasm */
1406     ierr = PetscOptionsBool("-pc_gamg_use_agg_gasm",
1407                             "Use aggregation agragates for GASM smoother (false)",
1408                             "PCGAMGUseASMAggs",
1409                             pc_gamg->use_aggs_in_gasm,
1410                             &pc_gamg->use_aggs_in_gasm,
1411                             &flag);CHKERRQ(ierr);
1412     /* -pc_gamg_process_eq_limit */
1413     ierr = PetscOptionsInt("-pc_gamg_process_eq_limit",
1414                            "Limit (goal) on number of equations per process on coarse grids",
1415                            "PCGAMGSetProcEqLim",
1416                            pc_gamg->min_eq_proc,
1417                            &pc_gamg->min_eq_proc,
1418                            &flag);CHKERRQ(ierr);
1419     /* -pc_gamg_coarse_eq_limit */
1420     ierr = PetscOptionsInt("-pc_gamg_coarse_eq_limit",
1421                            "Limit on number of equations for the coarse grid",
1422                            "PCGAMGSetCoarseEqLim",
1423                            pc_gamg->coarse_eq_limit,
1424                            &pc_gamg->coarse_eq_limit,
1425                            &flag);CHKERRQ(ierr);
1426     /* -pc_gamg_threshold */
1427     ierr = PetscOptionsReal("-pc_gamg_threshold",
1428                             "Relative threshold to use for dropping edges in aggregation graph",
1429                             "PCGAMGSetThreshold",
1430                             pc_gamg->threshold,
1431                             &pc_gamg->threshold,
1432                             &flag);CHKERRQ(ierr);
1433     if (flag && pc_gamg->verbose) {
1434       ierr = PetscPrintf(comm,"\t[%d]%s threshold set %e\n",0,__FUNCT__,pc_gamg->threshold);CHKERRQ(ierr);
1435     }
1436 
1437     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1438     ierr = PetscOptionsInt("-pc_mg_levels",
1439                            "Set number of MG levels",
1440                            "PCGAMGSetNlevels",
1441                            pc_gamg->Nlevels,
1442                            &pc_gamg->Nlevels,
1443                            &flag);CHKERRQ(ierr);
1444   }
1445   ierr = PetscOptionsTail();CHKERRQ(ierr);
1446   PetscFunctionReturn(0);
1447 }
1448 
1449 /* -------------------------------------------------------------------------- */
1450 /*MC
1451      PCGAMG - Geometric algebraic multigrid (AMG) preconditioning framework.
1452        - This is the entry point to GAMG, registered in pcregis.c
1453 
1454    Options Database Keys:
1455    Multigrid options(inherited)
1456 +  -pc_mg_cycles <1>: 1 for V cycle, 2 for W-cycle (PCMGSetCycleType)
1457 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
1458 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
1459 -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade
1460 
1461   Level: intermediate
1462 
1463   Concepts: multigrid
1464 
1465 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC, PCMGType,
1466            PCMGSetLevels(), PCMGGetLevels(), PCMGSetType(), PCMGSetCycleType(), PCMGSetNumberSmoothDown(),
1467            PCMGSetNumberSmoothUp(), PCMGGetCoarseSolve(), PCMGSetResidual(), PCMGSetInterpolation(),
1468            PCMGSetRestriction(), PCMGGetSmoother(), PCMGGetSmootherUp(), PCMGGetSmootherDown(),
1469            PCMGSetCyclesOnLevel(), PCMGSetRhs(), PCMGSetX(), PCMGSetR()
1470 M*/
1471 EXTERN_C_BEGIN
1472 #undef __FUNCT__
1473 #define __FUNCT__ "PCCreate_GAMG"
1474 PetscErrorCode  PCCreate_GAMG(PC pc)
1475 {
1476   PetscErrorCode ierr;
1477   PC_GAMG        *pc_gamg;
1478   PC_MG          *mg;
1479 #if defined PETSC_GAMG_USE_LOG
1480   static long count = 0;
1481 #endif
1482 
1483   PetscFunctionBegin;
1484   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1485   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr); /* calls PCCreate_MG() and MGCreate_Private() */
1486   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1487 
1488   /* create a supporting struct and attach it to pc */
1489   ierr         = PetscNewLog(pc, PC_GAMG, &pc_gamg);CHKERRQ(ierr);
1490   mg           = (PC_MG*)pc->data;
1491   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally */
1492   mg->innerctx = pc_gamg;
1493 
1494   pc_gamg->setup_count = 0;
1495   /* these should be in subctx but repartitioning needs simple arrays */
1496   pc_gamg->data_sz = 0;
1497   pc_gamg->data    = 0;
1498 
1499   /* register AMG type */
1500   if (!GAMGList) {
1501     ierr = PetscFunctionListAdd(PETSC_COMM_WORLD,&GAMGList,GAMGGEO,"PCCreateGAMG_GEO",(void (*)(void))PCCreateGAMG_GEO);CHKERRQ(ierr);
1502     ierr = PetscFunctionListAdd(PETSC_COMM_WORLD,&GAMGList,GAMGAGG,"PCCreateGAMG_AGG",(void (*)(void))PCCreateGAMG_AGG);CHKERRQ(ierr);
1503   }
1504 
1505   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
1506   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
1507   pc->ops->setup          = PCSetUp_GAMG;
1508   pc->ops->reset          = PCReset_GAMG;
1509   pc->ops->destroy        = PCDestroy_GAMG;
1510 
1511   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1512                                            "PCGAMGSetProcEqLim_C",
1513                                            "PCGAMGSetProcEqLim_GAMG",
1514                                            PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1515   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1516                                            "PCGAMGSetCoarseEqLim_C",
1517                                            "PCGAMGSetCoarseEqLim_GAMG",
1518                                            PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1519   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1520                                            "PCGAMGSetRepartitioning_C",
1521                                            "PCGAMGSetRepartitioning_GAMG",
1522                                            PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1523   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1524                                            "PCGAMGSetReuseProl_C",
1525                                            "PCGAMGSetReuseProl_GAMG",
1526                                            PCGAMGSetReuseProl_GAMG);CHKERRQ(ierr);
1527   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1528                                            "PCGAMGSetUseASMAggs_C",
1529                                            "PCGAMGSetUseASMAggs_GAMG",
1530                                            PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1531   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1532                                            "PCGAMGSetThreshold_C",
1533                                            "PCGAMGSetThreshold_GAMG",
1534                                            PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1535   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,
1536                                            "PCGAMGSetType_C",
1537                                            "PCGAMGSetType_GAMG",
1538                                            PCGAMGSetType_GAMG);CHKERRQ(ierr);
1539   pc_gamg->repart           = PETSC_FALSE;
1540   pc_gamg->reuse_prol       = PETSC_TRUE;
1541   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
1542   pc_gamg->min_eq_proc      = 50;
1543   pc_gamg->coarse_eq_limit  = 800;
1544   pc_gamg->threshold        = 0.001;
1545   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
1546   pc_gamg->verbose          = 0;
1547   pc_gamg->emax_id          = -1;
1548   pc_gamg->eigtarget[0]     = 0.05;
1549   pc_gamg->eigtarget[1]     = 1.05;
1550 
1551   /* private events */
1552 #if defined PETSC_GAMG_USE_LOG
1553   if (count++ == 0) {
1554     ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1555     ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
1556     /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
1557     /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
1558     /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
1559     ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1560     ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1561     ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1562     ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1563     ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1564     ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1565     ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1566     ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1567     ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1568     ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1569     ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1570     ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1571 
1572     /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
1573     /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
1574     /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
1575     /* create timer stages */
1576 #if defined GAMG_STAGES
1577     {
1578       char     str[32];
1579       PetscInt lidx;
1580       sprintf(str,"MG Level %d (finest)",0);
1581       ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1582       for (lidx=1; lidx<9; lidx++) {
1583         sprintf(str,"MG Level %d",lidx);
1584         ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1585       }
1586     }
1587 #endif
1588   }
1589 #endif
1590   /* general events */
1591 #if defined PETSC_USE_LOG
1592   ierr = PetscLogEventRegister("PCGAMGgraph_AGG", 0, &PC_GAMGGgraph_AGG);CHKERRQ(ierr);
1593   ierr = PetscLogEventRegister("PCGAMGgraph_GEO", PC_CLASSID, &PC_GAMGGgraph_GEO);CHKERRQ(ierr);
1594   ierr = PetscLogEventRegister("PCGAMGcoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1595   ierr = PetscLogEventRegister("PCGAMGcoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1596   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1597   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1598   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptprol_AGG);CHKERRQ(ierr);
1599   ierr = PetscLogEventRegister("GAMGKKTProl_AGG", PC_CLASSID, &PC_GAMGKKTProl_AGG);CHKERRQ(ierr);
1600 #endif
1601 
1602   /* instantiate derived type */
1603   ierr = PetscOptionsHead("GAMG options");CHKERRQ(ierr);
1604   {
1605     char tname[256] = GAMGAGG;
1606     ierr = PetscOptionsList("-pc_gamg_type","Type of GAMG method","PCGAMGSetType",GAMGList, tname, tname, sizeof(tname), NULL);CHKERRQ(ierr);
1607     ierr = PCGAMGSetType(pc, tname);CHKERRQ(ierr);
1608   }
1609   ierr = PetscOptionsTail();CHKERRQ(ierr);
1610   PetscFunctionReturn(0);
1611 }
1612 EXTERN_C_END
1613