xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision b20b4189892be55dc38d9c19ce94b8fae3144b76)
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 PetscLogEvent PC_GAMGKKTProl_AGG;
22 #endif
23 
24 #define GAMG_MAXLEVELS 30
25 
26 /* #define GAMG_STAGES */
27 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
28 static PetscLogStage gamg_stages[GAMG_MAXLEVELS];
29 #endif
30 
31 static PetscFunctionList GAMGList = 0;
32 static PetscBool PCGAMGPackageInitialized;
33 
34 /* ----------------------------------------------------------------------------- */
35 #undef __FUNCT__
36 #define __FUNCT__ "PCReset_GAMG"
37 PetscErrorCode PCReset_GAMG(PC pc)
38 {
39   PetscErrorCode ierr;
40   PC_MG          *mg      = (PC_MG*)pc->data;
41   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
42 
43   PetscFunctionBegin;
44   if (pc_gamg->data) { /* this should not happen, cleaned up in SetUp */
45     PetscPrintf(PetscObjectComm((PetscObject)pc),"***[%d]%s this should not happen, cleaned up in SetUp\n",0,__FUNCT__);
46     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
47   }
48   pc_gamg->data = NULL; pc_gamg->data_sz = 0;
49 
50   if (pc_gamg->orig_data) {
51     ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
52   }
53   PetscFunctionReturn(0);
54 }
55 
56 /* private 2x2 Mat Nest for Stokes */
57 typedef struct {
58   Mat A11,A21,A12,Amat;
59   IS  prim_is,constr_is;
60 } GAMGKKTMat;
61 
62 #undef __FUNCT__
63 #define __FUNCT__ "GAMGKKTMatCreate"
64 static PetscErrorCode GAMGKKTMatCreate(Mat A, PetscBool iskkt, GAMGKKTMat *out)
65 {
66   PetscFunctionBegin;
67   out->Amat = A;
68   if (iskkt) {
69     PetscErrorCode ierr;
70     IS             is_constraint, is_prime;
71     PetscInt       nmin,nmax;
72 
73     ierr = MatGetOwnershipRange(A, &nmin, &nmax);CHKERRQ(ierr);
74     ierr = MatFindZeroDiagonals(A, &is_constraint);CHKERRQ(ierr);
75     ierr = ISComplement(is_constraint, nmin, nmax, &is_prime);CHKERRQ(ierr);
76 
77     out->prim_is   = is_prime;
78     out->constr_is = is_constraint;
79 
80     ierr = MatGetSubMatrix(A, is_prime, is_prime,      MAT_INITIAL_MATRIX, &out->A11);CHKERRQ(ierr);
81     ierr = MatGetSubMatrix(A, is_prime, is_constraint, MAT_INITIAL_MATRIX, &out->A12);CHKERRQ(ierr);
82     ierr = MatGetSubMatrix(A, is_constraint, is_prime, MAT_INITIAL_MATRIX, &out->A21);CHKERRQ(ierr);
83   } else {
84     out->A11       = A;
85     out->A21       = NULL;
86     out->A12       = NULL;
87     out->prim_is   = NULL;
88     out->constr_is = NULL;
89   }
90   PetscFunctionReturn(0);
91 }
92 
93 #undef __FUNCT__
94 #define __FUNCT__ "GAMGKKTMatDestroy"
95 static PetscErrorCode GAMGKKTMatDestroy(GAMGKKTMat *mat)
96 {
97   PetscErrorCode ierr;
98 
99   PetscFunctionBegin;
100   if (mat->A11 && mat->A11 != mat->Amat) {
101     ierr = MatDestroy(&mat->A11);CHKERRQ(ierr);
102   }
103   ierr = MatDestroy(&mat->A21);CHKERRQ(ierr);
104   ierr = MatDestroy(&mat->A12);CHKERRQ(ierr);
105 
106   ierr = ISDestroy(&mat->prim_is);CHKERRQ(ierr);
107   ierr = ISDestroy(&mat->constr_is);CHKERRQ(ierr);
108   PetscFunctionReturn(0);
109 }
110 
111 /* -------------------------------------------------------------------------- */
112 /*
113    createLevel: create coarse op with RAP.  repartition and/or reduce number
114      of active processors.
115 
116    Input Parameter:
117    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
118           'pc_gamg->data_sz' are changed via repartitioning/reduction.
119    . Amat_fine - matrix on this fine (k) level
120    . cr_bs - coarse block size
121    . isLast -
122    . stokes -
123    In/Output Parameter:
124    . a_P_inout - prolongation operator to the next level (k-->k-1)
125    . a_nactive_proc - number of active procs
126    Output Parameter:
127    . a_Amat_crs - coarse matrix that is created (k-1)
128 */
129 
130 #undef __FUNCT__
131 #define __FUNCT__ "createLevel"
132 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)
133 {
134   PetscErrorCode  ierr;
135   PC_MG           *mg         = (PC_MG*)pc->data;
136   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
137   const PetscBool repart      = pc_gamg->repart;
138   const PetscInt  min_eq_proc = pc_gamg->min_eq_proc, coarse_max = pc_gamg->coarse_eq_limit;
139   Mat             Cmat,Pold=*a_P_inout;
140   MPI_Comm        comm;
141   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
142   PetscInt        ncrs_eq,ncrs_prim,f_bs;
143 
144   PetscFunctionBegin;
145   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
146   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
147   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
148   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
149   /* RAP */
150   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
151 
152   /* set 'ncrs_prim' (nodes), 'ncrs_eq' (equations)*/
153   ncrs_prim = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
154   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);
155   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
156 
157   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
158   {
159     PetscInt ncrs_eq_glob;
160     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
161     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
162     if (new_size == 0 || ncrs_eq_glob < coarse_max) new_size = 1;
163     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
164     if (isLast) new_size = 1;
165   }
166 
167   if (!repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
168   else {
169     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
170     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_prim_new,ncrs_eq_new,nloc_old;
171     IS             is_eq_newproc,is_eq_newproc_prim,is_eq_num,is_eq_num_prim,isscat,new_eq_indices;
172     VecScatter     vecscat;
173     PetscScalar    *array;
174     Vec            src_crd, dest_crd;
175 
176     nloc_old = ncrs_eq/cr_bs;
177     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);
178 #if defined PETSC_GAMG_USE_LOG
179     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
180 #endif
181     /* make 'is_eq_newproc' */
182     ierr = PetscMalloc(size*sizeof(PetscInt), &counts);CHKERRQ(ierr);
183     if (repart && !stokes) {
184       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
185       Mat adj;
186 
187       if (pc_gamg->verbose>0) {
188         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);
189         else {
190           PetscInt n;
191           ierr = MPI_Allreduce(&ncrs_eq, &n, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
192           PetscPrintf(comm,"\t[%d]%s repartition: size (active): %d --> %d, neq = %d\n",rank,__FUNCT__,*a_nactive_proc,new_size,n);
193         }
194       }
195 
196       /* get 'adj' */
197       if (cr_bs == 1) {
198         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
199       } else {
200         /* make a scalar matrix to partition (no Stokes here) */
201         Mat               tMat;
202         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
203         const PetscScalar *vals;
204         const PetscInt    *idx;
205         PetscInt          *d_nnz, *o_nnz, M, N;
206         static PetscInt   llev = 0;
207 
208         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &d_nnz);CHKERRQ(ierr);
209         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &o_nnz);CHKERRQ(ierr);
210         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
211         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
212         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
213           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
214           d_nnz[jj] = ncols/cr_bs;
215           o_nnz[jj] = ncols/cr_bs;
216           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
217           if (d_nnz[jj] > ncrs_prim) d_nnz[jj] = ncrs_prim;
218           if (o_nnz[jj] > (M/cr_bs-ncrs_prim)) o_nnz[jj] = M/cr_bs-ncrs_prim;
219         }
220 
221         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
222         ierr = MatSetSizes(tMat, ncrs_prim, ncrs_prim,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
223         ierr = MatSetType(tMat,MATAIJ);CHKERRQ(ierr);
224         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
225         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
226         ierr = PetscFree(d_nnz);CHKERRQ(ierr);
227         ierr = PetscFree(o_nnz);CHKERRQ(ierr);
228 
229         for (ii = Istart_crs; ii < Iend_crs; ii++) {
230           PetscInt dest_row = ii/cr_bs;
231           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
232           for (jj = 0; jj < ncols; jj++) {
233             PetscInt    dest_col = idx[jj]/cr_bs;
234             PetscScalar v        = 1.0;
235             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
236           }
237           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
238         }
239         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
240         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
241 
242         if (llev++ == -1) {
243           PetscViewer viewer; char fname[32];
244           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
245           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
246           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
247           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
248         }
249 
250         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
251 
252         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
253       } /* create 'adj' */
254 
255       { /* partition: get newproc_idx */
256         char            prefix[256];
257         const char      *pcpre;
258         const PetscInt  *is_idx;
259         MatPartitioning mpart;
260         IS              proc_is;
261         PetscInt        targetPE;
262 
263         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
264         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
265         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
266         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
267         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
268         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
269         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
270         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
271         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
272 
273         /* collect IS info */
274         ierr     = PetscMalloc(ncrs_eq*sizeof(PetscInt), &newproc_idx);CHKERRQ(ierr);
275         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
276         targetPE = 1; /* bring to "front" of machine */
277         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
278         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
279           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
280             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
281           }
282         }
283         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
284         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
285       }
286       ierr = MatDestroy(&adj);CHKERRQ(ierr);
287 
288       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
289       if (newproc_idx != 0) {
290         ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
291       }
292     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
293 
294       PetscInt rfactor,targetPE;
295       /* find factor */
296       if (new_size == 1) rfactor = size; /* easy */
297       else {
298         PetscReal best_fact = 0.;
299         jj = -1;
300         for (kk = 1 ; kk <= size ; kk++) {
301           if (size%kk==0) { /* a candidate */
302             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
303             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
304             if (fact > best_fact) {
305               best_fact = fact; jj = kk;
306             }
307           }
308         }
309         if (jj != -1) rfactor = jj;
310         else rfactor = 1; /* does this happen .. a prime */
311       }
312       new_size = size/rfactor;
313 
314       if (new_size==nactive) {
315         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
316         ierr        = PetscFree(counts);CHKERRQ(ierr);
317         if (pc_gamg->verbose>0) {
318           PetscPrintf(comm,"\t[%d]%s aggregate processors noop: new_size=%d, neq(loc)=%d\n",rank,__FUNCT__,new_size,ncrs_eq);
319         }
320         PetscFunctionReturn(0);
321       }
322 
323       if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s number of equations (loc) %d with simple aggregation\n",rank,__FUNCT__,ncrs_eq);
324       targetPE = rank/rfactor;
325       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
326 
327       if (stokes) {
328         ierr = ISCreateStride(comm, ncrs_prim*cr_bs, targetPE, 0, &is_eq_newproc_prim);CHKERRQ(ierr);
329       }
330     } /* end simple 'is_eq_newproc' */
331 
332     /*
333      Create an index set from the is_eq_newproc index set to indicate the mapping TO
334      */
335     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
336     if (stokes) {
337       ierr = ISPartitioningToNumbering(is_eq_newproc_prim, &is_eq_num_prim);CHKERRQ(ierr);
338     } else is_eq_num_prim = is_eq_num;
339     /*
340       Determine how many equations/vertices are assigned to each processor
341      */
342     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
343     ncrs_eq_new = counts[rank];
344     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
345     if (stokes) {
346       ierr          = ISPartitioningCount(is_eq_newproc_prim, size, counts);CHKERRQ(ierr);
347       ierr          = ISDestroy(&is_eq_newproc_prim);CHKERRQ(ierr);
348       ncrs_prim_new = counts[rank]/cr_bs; /* nodes */
349     } else ncrs_prim_new = ncrs_eq_new/cr_bs; /* eqs */
350 
351     ierr = PetscFree(counts);CHKERRQ(ierr);
352 #if defined PETSC_GAMG_USE_LOG
353     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
354 #endif
355 
356     /* move data (for primal equations only) */
357     /* Create a vector to contain the newly ordered element information */
358     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
359     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_prim_new, PETSC_DECIDE);CHKERRQ(ierr);
360     ierr = VecSetFromOptions(dest_crd);CHKERRQ(ierr); /* this is needed! */
361     /*
362      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
363      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
364      */
365     ierr = PetscMalloc((ncrs_prim*node_data_sz)*sizeof(PetscInt), &tidx);CHKERRQ(ierr);
366     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
367     for (ii=0,jj=0; ii<ncrs_prim; ii++) {
368       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
369       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
370     }
371     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
372     ierr = ISCreateGeneral(comm, node_data_sz*ncrs_prim, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
373     ierr = PetscFree(tidx);CHKERRQ(ierr);
374     /*
375      Create a vector to contain the original vertex information for each element
376      */
377     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs_prim, &src_crd);CHKERRQ(ierr);
378     for (jj=0; jj<ndata_cols; jj++) {
379       const PetscInt stride0=ncrs_prim*pc_gamg->data_cell_rows;
380       for (ii=0; ii<ncrs_prim; ii++) {
381         for (kk=0; kk<ndata_rows; kk++) {
382           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
383           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
384           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
385         }
386       }
387     }
388     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
389     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
390     /*
391       Scatter the element vertex information (still in the original vertex ordering)
392       to the correct processor
393     */
394     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
395     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
396     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
397     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
398     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
399     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
400     /*
401       Put the element vertex data into a new allocation of the gdata->ele
402     */
403     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
404     ierr = PetscMalloc(node_data_sz*ncrs_prim_new*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
405 
406     pc_gamg->data_sz = node_data_sz*ncrs_prim_new;
407     strideNew        = ncrs_prim_new*ndata_rows;
408 
409     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
410     for (jj=0; jj<ndata_cols; jj++) {
411       for (ii=0; ii<ncrs_prim_new; ii++) {
412         for (kk=0; kk<ndata_rows; kk++) {
413           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
414           pc_gamg->data[ix] = PetscRealPart(array[jx]);
415         }
416       }
417     }
418     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
419     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
420 
421     /* move A and P (columns) with new layout */
422 #if defined PETSC_GAMG_USE_LOG
423     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
424 #endif
425 
426     /*
427       Invert for MatGetSubMatrix
428     */
429     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
430     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
431     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
432     if (is_eq_num != is_eq_num_prim) {
433       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
434     }
435     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
436 #if defined PETSC_GAMG_USE_LOG
437     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
438     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
439 #endif
440     /* 'a_Amat_crs' output */
441     {
442       Mat mat;
443       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
444       *a_Amat_crs = mat;
445 
446       if (!PETSC_TRUE) {
447         PetscInt cbs, rbs;
448         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
449         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
450         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
451         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);
452       }
453     }
454     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
455 
456 #if defined PETSC_GAMG_USE_LOG
457     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
458 #endif
459     /* prolongator */
460     {
461       IS       findices;
462       PetscInt Istart,Iend;
463       Mat      Pnew;
464       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
465 #if defined PETSC_GAMG_USE_LOG
466       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
467 #endif
468       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
469       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
470       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
471       ierr = ISDestroy(&findices);CHKERRQ(ierr);
472 
473       if (!PETSC_TRUE) {
474         PetscInt cbs, rbs;
475         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
476         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
477         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
478         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
479       }
480 #if defined PETSC_GAMG_USE_LOG
481       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
482 #endif
483       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
484 
485       /* output - repartitioned */
486       *a_P_inout = Pnew;
487     }
488     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
489 
490     *a_nactive_proc = new_size; /* output */
491   }
492 
493   /* outout matrix data */
494   if (!PETSC_TRUE) {
495     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
496     if (llev==0) {
497       sprintf(fname,"Cmat_%d.m",llev++);
498       PetscViewerASCIIOpen(comm,fname,&viewer);
499       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
500       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
501       ierr = PetscViewerDestroy(&viewer);
502     }
503     sprintf(fname,"Cmat_%d.m",llev++);
504     PetscViewerASCIIOpen(comm,fname,&viewer);
505     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
506     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
507     ierr = PetscViewerDestroy(&viewer);
508   }
509   PetscFunctionReturn(0);
510 }
511 
512 /* -------------------------------------------------------------------------- */
513 /*
514    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
515                     by setting data structures and options.
516 
517    Input Parameter:
518 .  pc - the preconditioner context
519 
520    Application Interface Routine: PCSetUp()
521 
522    Notes:
523    The interface routine PCSetUp() is not usually called directly by
524    the user, but instead is called by PCApply() if necessary.
525 */
526 #undef __FUNCT__
527 #define __FUNCT__ "PCSetUp_GAMG"
528 PetscErrorCode PCSetUp_GAMG(PC pc)
529 {
530   PetscErrorCode ierr;
531   PC_MG          *mg      = (PC_MG*)pc->data;
532   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
533   Mat            Pmat     = pc->pmat;
534   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
535   MPI_Comm       comm;
536   PetscMPIInt    rank,size,nactivepe;
537   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
538   PetscReal      emaxs[GAMG_MAXLEVELS];
539   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
540   GAMGKKTMat     kktMatsArr[GAMG_MAXLEVELS];
541   PetscLogDouble nnz0=0.,nnztot=0.;
542   MatInfo        info;
543   PetscBool      stokes = PETSC_FALSE, redo_mesh_setup = (PetscBool)(!pc_gamg->reuse_prol);
544 
545   PetscFunctionBegin;
546   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
547   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
548   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
549 
550   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);
551 
552   if (pc_gamg->setup_count++ > 0) {
553     if (redo_mesh_setup) {
554       /* reset everything */
555       ierr = PCReset_MG(pc);CHKERRQ(ierr);
556       pc->setupcalled = 0;
557     } else {
558       PC_MG_Levels **mglevels = mg->levels;
559       /* just do Galerkin grids */
560       Mat          B,dA,dB;
561 
562      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
563       if (pc_gamg->Nlevels > 1) {
564         /* currently only handle case where mat and pmat are the same on coarser levels */
565         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB,NULL);CHKERRQ(ierr);
566         /* (re)set to get dirty flag */
567         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
568 
569         for (level=pc_gamg->Nlevels-2; level>=0; level--) {
570           /* the first time through the matrix structure has changed from repartitioning */
571           if (pc_gamg->setup_count==2 && (pc_gamg->repart || level==0)) {
572             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
573             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
574 
575             mglevels[level]->A = B;
576           } else {
577             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B,NULL);CHKERRQ(ierr);
578             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
579           }
580           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
581           dB   = B;
582         }
583       }
584 
585       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
586 
587       /* PCSetUp_MG seems to insists on setting this to GMRES */
588       ierr = KSPSetType(mglevels[0]->smoothd, KSPPREONLY);CHKERRQ(ierr);
589       PetscFunctionReturn(0);
590     }
591   }
592 
593   ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr);
594 
595   ierr = GAMGKKTMatCreate(Pmat, stokes, &kktMatsArr[0]);CHKERRQ(ierr);
596 
597   if (!pc_gamg->data) {
598     if (pc_gamg->orig_data) {
599       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
600       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
601 
602       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
603       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
604       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;
605 
606       ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
607       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
608     } else {
609       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
610       if (stokes) SETERRQ(comm,PETSC_ERR_PLIB,"Need data (eg, PCSetCoordinates) for Stokes problems");
611       ierr = pc_gamg->ops->createdefaultdata(pc, kktMatsArr[0].A11);CHKERRQ(ierr);
612     }
613   }
614 
615   /* cache original data for reuse */
616   if (!pc_gamg->orig_data && redo_mesh_setup) {
617     ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->orig_data);CHKERRQ(ierr);
618     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
619     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
620     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
621   }
622 
623   /* get basic dims */
624   if (stokes) bs = pc_gamg->data_cell_rows; /* this is agg-mg specific */
625   else {
626     ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
627   }
628 
629   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
630   if (pc_gamg->verbose) {
631     PetscInt NN = M;
632     if (pc_gamg->verbose==1) {
633       ierr =  MatGetInfo(Pmat,MAT_LOCAL,&info);CHKERRQ(ierr);
634       ierr = MatGetLocalSize(Pmat, &NN, &qq);CHKERRQ(ierr);
635     } else {
636       ierr = MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr);
637     }
638     nnz0   = info.nz_used;
639     nnztot = info.nz_used;
640     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",
641                          rank,__FUNCT__,0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
642                          (int)(nnz0/(PetscReal)NN),size);CHKERRQ(ierr);
643   }
644 
645   /* Get A_i and R_i */
646   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
647        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);  /* && (size==1 || nactivepe>1); */
648        level++) {
649     level1 = level + 1;
650 #if defined PETSC_GAMG_USE_LOG
651     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
652 #if (defined GAMG_STAGES)
653     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
654 #endif
655 #endif
656     /* deal with Stokes, get sub matrices */
657     if (level > 0) {
658       ierr = GAMGKKTMatCreate(Aarr[level], stokes, &kktMatsArr[level]);CHKERRQ(ierr);
659     }
660     { /* construct prolongator */
661       Mat              Gmat;
662       PetscCoarsenData *agg_lists;
663       Mat              Prol11,Prol22;
664 
665       ierr = pc_gamg->ops->graph(pc,kktMatsArr[level].A11, &Gmat);CHKERRQ(ierr);
666       ierr = pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
667       ierr = pc_gamg->ops->prolongator(pc, kktMatsArr[level].A11, Gmat, agg_lists, &Prol11);CHKERRQ(ierr);
668 
669       /* could have failed to create new level */
670       if (Prol11) {
671         /* get new block size of coarse matrices */
672         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
673 
674         if (stokes) {
675           if (!pc_gamg->ops->formkktprol) SETERRQ(comm,PETSC_ERR_USER,"Stokes not supportd by AMG method.");
676           /* R A12 == (T = A21 P)';  G = T' T; coarsen G; form plain agg with G */
677           ierr = pc_gamg->ops->formkktprol(pc, Prol11, kktMatsArr[level].A21, &Prol22);CHKERRQ(ierr);
678         }
679 
680         if (pc_gamg->ops->optprol) {
681           /* smooth */
682           ierr = pc_gamg->ops->optprol(pc, kktMatsArr[level].A11, &Prol11);CHKERRQ(ierr);
683         }
684 
685         if (stokes) {
686           IS  is_row[2];
687           Mat a[4];
688 
689           is_row[0] = kktMatsArr[level].prim_is; is_row[1] = kktMatsArr[level].constr_is;
690           a[0]      = Prol11; a[1] = NULL; a[2] = NULL; a[3] = Prol22;
691           ierr      = MatCreateNest(comm,2,is_row, 2, is_row, a, &Parr[level1]);CHKERRQ(ierr);
692         } else Parr[level1] = Prol11;
693       } else Parr[level1] = NULL;
694 
695       if (pc_gamg->use_aggs_in_gasm) {
696         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
697       }
698 
699       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
700       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
701     } /* construct prolongator scope */
702 #if defined PETSC_GAMG_USE_LOG
703     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
704 #endif
705     /* cache eigen estimate */
706     if (pc_gamg->emax_id != -1) {
707       PetscBool flag;
708       ierr = PetscObjectComposedDataGetReal((PetscObject)kktMatsArr[level].A11, pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
709       if (!flag) emaxs[level] = -1.;
710     } else emaxs[level] = -1.;
711     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
712     if (!Parr[level1]) {
713       if (pc_gamg->verbose) {
714         ierr =  PetscPrintf(comm,"\t[%d]%s stop gridding, level %d\n",rank,__FUNCT__,level);CHKERRQ(ierr);
715       }
716       break;
717     }
718 #if defined PETSC_GAMG_USE_LOG
719     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
720 #endif
721 
722     ierr = createLevel(pc, Aarr[level], bs, (PetscBool)(level==pc_gamg->Nlevels-2),
723                        stokes, &Parr[level1], &Aarr[level1], &nactivepe);CHKERRQ(ierr);
724 
725 #if defined PETSC_GAMG_USE_LOG
726     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
727 #endif
728     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
729 
730     if (pc_gamg->verbose > 0) {
731       PetscInt NN = M;
732       if (pc_gamg->verbose==1) {
733         ierr = MatGetInfo(Aarr[level1],MAT_LOCAL,&info);CHKERRQ(ierr);
734         ierr = MatGetLocalSize(Aarr[level1], &NN, &qq);CHKERRQ(ierr);
735       } else {
736         ierr = MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
737       }
738 
739       nnztot += info.nz_used;
740       ierr    = PetscPrintf(comm,"\t\t[%d]%s %d) N=%d, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",
741                             rank,__FUNCT__,(int)level1,M,pc_gamg->data_cell_cols,
742                             (int)(info.nz_used/(PetscReal)NN), nactivepe);CHKERRQ(ierr);
743     }
744 
745     /* stop if one node -- could pull back for singular problems */
746     if (M/pc_gamg->data_cell_cols < 2) {
747       level++;
748       break;
749     }
750 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
751     ierr = PetscLogStagePop();CHKERRQ(ierr);
752 #endif
753   } /* levels */
754 
755   if (pc_gamg->data) {
756     ierr          = PetscFree(pc_gamg->data);CHKERRQ(ierr);
757     pc_gamg->data = NULL;
758   }
759 
760   if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s %d levels, grid complexity = %g\n",0,__FUNCT__,level+1,nnztot/nnz0);
761   pc_gamg->Nlevels = level + 1;
762   fine_level       = level;
763   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
764 
765   /* simple setup */
766   if (!PETSC_TRUE) {
767     PC_MG_Levels **mglevels = mg->levels;
768     for (lidx=0,level=pc_gamg->Nlevels-1;
769          lidx<fine_level;
770          lidx++, level--) {
771       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
772       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
773       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
774       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
775     }
776     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
777 
778     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
779   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
780     /* set default smoothers & set operators */
781     for (lidx = 1, level = pc_gamg->Nlevels-2;
782          lidx <= fine_level;
783          lidx++, level--) {
784       KSP smoother;
785       PC  subpc;
786 
787       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
788       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
789 
790       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
791       /* set ops */
792       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
793       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
794 
795       /* create field split PC, get subsmoother */
796       if (stokes) {
797         KSP      *ksps;
798         PetscInt nn;
799         ierr     = PCFieldSplitSetIS(subpc,"0",kktMatsArr[level].prim_is);CHKERRQ(ierr);
800         ierr     = PCFieldSplitSetIS(subpc,"1",kktMatsArr[level].constr_is);CHKERRQ(ierr);
801         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
802         smoother = ksps[0];
803         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
804         ierr     = PetscFree(ksps);CHKERRQ(ierr);
805       }
806       ierr = GAMGKKTMatDestroy(&kktMatsArr[level]);CHKERRQ(ierr);
807 
808       /* set defaults */
809       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
810 
811       /* override defaults and command line args (!) */
812       if (pc_gamg->use_aggs_in_gasm) {
813         PetscInt sz;
814         IS       *is;
815 
816         sz   = nASMBlocksArr[level];
817         is   = ASMLocalIDsArr[level];
818         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
819         if (sz==0) {
820           IS       is;
821           PetscInt my0,kk;
822           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
823           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
824           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
825           ierr = ISDestroy(&is);CHKERRQ(ierr);
826         } else {
827           PetscInt kk;
828           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
829           for (kk=0; kk<sz; kk++) {
830             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
831           }
832           ierr = PetscFree(is);CHKERRQ(ierr);
833         }
834         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
835 
836         ASMLocalIDsArr[level] = NULL;
837         nASMBlocksArr[level]  = 0;
838         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
839       } else {
840         ierr = PCSetType(subpc, PCJACOBI);CHKERRQ(ierr);
841       }
842     }
843     {
844       /* coarse grid */
845       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
846       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
847       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
848       ierr = KSPSetOperators(smoother, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
849       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
850       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
851       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
852       ierr = PCSetUp(subpc);CHKERRQ(ierr);
853       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
854       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
855       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
856       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
857       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
858       ierr = KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);CHKERRQ(ierr);
859       /* This flag gets reset by PCBJacobiGetSubKSP(), but our BJacobi really does the same algorithm everywhere (and in
860        * fact, all but one process will have zero dofs), so we reset the flag to avoid having PCView_BJacobi attempt to
861        * view every subdomain as though they were different. */
862       ((PC_BJacobi*)subpc->data)->same_local_solves = PETSC_TRUE;
863     }
864 
865     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
866     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
867     ierr = PCSetFromOptions_MG(pc);CHKERRQ(ierr);
868     ierr = PetscOptionsEnd();CHKERRQ(ierr);
869     if (mg->galerkin != 2) SETERRQ(comm,PETSC_ERR_USER,"GAMG does Galerkin manually so the -pc_mg_galerkin option must not be used.");
870 
871     /* create cheby smoothers */
872     for (lidx = 1, level = pc_gamg->Nlevels-2;
873          lidx <= fine_level;
874          lidx++, level--) {
875       KSP       smoother;
876       PetscBool flag;
877       PC        subpc;
878 
879       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
880       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
881 
882       /* create field split PC, get subsmoother */
883       if (stokes) {
884         KSP      *ksps;
885         PetscInt nn;
886         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
887         smoother = ksps[0];
888         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
889         ierr     = PetscFree(ksps);CHKERRQ(ierr);
890       }
891 
892       /* do my own cheby */
893       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
894       if (flag) {
895         PetscReal emax, emin;
896         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
897         if (flag && emaxs[level] > 0.0) emax=emaxs[level]; /* eigen estimate only for diagnal PC */
898         else { /* eigen estimate 'emax' */
899           KSP eksp;
900           Mat Lmat = Aarr[level];
901           Vec bb, xx;
902 
903           ierr = MatGetVecs(Lmat, &bb, 0);CHKERRQ(ierr);
904           ierr = MatGetVecs(Lmat, &xx, 0);CHKERRQ(ierr);
905           {
906             PetscRandom rctx;
907             ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
908             ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
909             ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
910             ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
911           }
912 
913           /* zeroing out BC rows -- needed for crazy matrices */
914           {
915             PetscInt    Istart,Iend,ncols,jj,Ii;
916             PetscScalar zero = 0.0;
917             ierr = MatGetOwnershipRange(Lmat, &Istart, &Iend);CHKERRQ(ierr);
918             for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
919               ierr = MatGetRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
920               if (ncols <= 1) {
921                 ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
922               }
923               ierr = MatRestoreRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
924             }
925             ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
926             ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
927           }
928 
929           ierr = KSPCreate(comm, &eksp);CHKERRQ(ierr);
930           ierr = KSPSetTolerances(eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10);CHKERRQ(ierr);
931           ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
932           ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
933           ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
934           ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
935 
936           ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
937           ierr = KSPSetOperators(eksp, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
938           ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
939 
940           /* set PC type to be same as smoother */
941           ierr = KSPSetPC(eksp, subpc);CHKERRQ(ierr);
942 
943           /* solve - keep stuff out of logging */
944           ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
945           ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
946           ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
947           ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
948           ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
949 
950           ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
951 
952           ierr = VecDestroy(&xx);CHKERRQ(ierr);
953           ierr = VecDestroy(&bb);CHKERRQ(ierr);
954           ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
955 
956           if (pc_gamg->verbose > 0) {
957             PetscInt N1, tt;
958             ierr = MatGetSize(Aarr[level], &N1, &tt);CHKERRQ(ierr);
959             PetscPrintf(comm,"\t\t\t%s PC setup max eigen=%e min=%e on level %d (N=%d)\n",__FUNCT__,emax,emin,lidx,N1);
960           }
961         }
962         {
963           PetscInt N1, N0;
964           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
965           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
966           /* heuristic - is this crap? */
967           /* emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); */
968           emin  = emax * pc_gamg->eigtarget[0];
969           emax *= pc_gamg->eigtarget[1];
970         }
971         ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
972       } /* setup checby flag */
973     } /* non-coarse levels */
974 
975     /* clean up */
976     for (level=1; level<pc_gamg->Nlevels; level++) {
977       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
978       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
979     }
980 
981     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
982 
983     if (PETSC_TRUE) {
984       KSP smoother;  /* PCSetUp_MG seems to insists on setting this to GMRES on coarse grid */
985       ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
986       ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
987     }
988   } else {
989     KSP smoother;
990     if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s one level solver used (system is seen as DD). Using default solver.\n",rank,__FUNCT__);
991     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
992     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
993     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
994     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
995   }
996   PetscFunctionReturn(0);
997 }
998 
999 /* ------------------------------------------------------------------------- */
1000 /*
1001  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
1002    that was created with PCCreate_GAMG().
1003 
1004    Input Parameter:
1005 .  pc - the preconditioner context
1006 
1007    Application Interface Routine: PCDestroy()
1008 */
1009 #undef __FUNCT__
1010 #define __FUNCT__ "PCDestroy_GAMG"
1011 PetscErrorCode PCDestroy_GAMG(PC pc)
1012 {
1013   PetscErrorCode ierr;
1014   PC_MG          *mg     = (PC_MG*)pc->data;
1015   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
1016 
1017   PetscFunctionBegin;
1018   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
1019   if (pc_gamg->ops->destroy) {
1020     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1021   }
1022   ierr = PetscFree(pc_gamg->ops);CHKERRQ(ierr);
1023   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1024   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
1025   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
1026   PetscFunctionReturn(0);
1027 }
1028 
1029 
1030 #undef __FUNCT__
1031 #define __FUNCT__ "PCGAMGSetProcEqLim"
1032 /*@
1033    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via
1034    processor reduction.
1035 
1036    Not Collective on PC
1037 
1038    Input Parameters:
1039 .  pc - the preconditioner context
1040 
1041 
1042    Options Database Key:
1043 .  -pc_gamg_process_eq_limit
1044 
1045    Level: intermediate
1046 
1047    Concepts: Unstructured multrigrid preconditioner
1048 
1049 .seealso: ()
1050 @*/
1051 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
1052 {
1053   PetscErrorCode ierr;
1054 
1055   PetscFunctionBegin;
1056   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1057   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1058   PetscFunctionReturn(0);
1059 }
1060 
1061 #undef __FUNCT__
1062 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
1063 static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
1064 {
1065   PC_MG   *mg      = (PC_MG*)pc->data;
1066   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1067 
1068   PetscFunctionBegin;
1069   if (n>0) pc_gamg->min_eq_proc = n;
1070   PetscFunctionReturn(0);
1071 }
1072 
1073 #undef __FUNCT__
1074 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
1075 /*@
1076    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
1077 
1078  Collective on PC
1079 
1080    Input Parameters:
1081 .  pc - the preconditioner context
1082 
1083 
1084    Options Database Key:
1085 .  -pc_gamg_coarse_eq_limit
1086 
1087    Level: intermediate
1088 
1089    Concepts: Unstructured multrigrid preconditioner
1090 
1091 .seealso: ()
1092  @*/
1093 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
1094 {
1095   PetscErrorCode ierr;
1096 
1097   PetscFunctionBegin;
1098   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1099   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1100   PetscFunctionReturn(0);
1101 }
1102 
1103 #undef __FUNCT__
1104 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
1105 static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
1106 {
1107   PC_MG   *mg      = (PC_MG*)pc->data;
1108   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1109 
1110   PetscFunctionBegin;
1111   if (n>0) pc_gamg->coarse_eq_limit = n;
1112   PetscFunctionReturn(0);
1113 }
1114 
1115 #undef __FUNCT__
1116 #define __FUNCT__ "PCGAMGSetRepartitioning"
1117 /*@
1118    PCGAMGSetRepartitioning - Repartition the coarse grids
1119 
1120    Collective on PC
1121 
1122    Input Parameters:
1123 .  pc - the preconditioner context
1124 
1125 
1126    Options Database Key:
1127 .  -pc_gamg_repartition
1128 
1129    Level: intermediate
1130 
1131    Concepts: Unstructured multrigrid preconditioner
1132 
1133 .seealso: ()
1134 @*/
1135 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
1136 {
1137   PetscErrorCode ierr;
1138 
1139   PetscFunctionBegin;
1140   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1141   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1142   PetscFunctionReturn(0);
1143 }
1144 
1145 #undef __FUNCT__
1146 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
1147 static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
1148 {
1149   PC_MG   *mg      = (PC_MG*)pc->data;
1150   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1151 
1152   PetscFunctionBegin;
1153   pc_gamg->repart = n;
1154   PetscFunctionReturn(0);
1155 }
1156 
1157 #undef __FUNCT__
1158 #define __FUNCT__ "PCGAMGSetReuseProl"
1159 /*@
1160    PCGAMGSetReuseProl - Reuse prlongation
1161 
1162    Collective on PC
1163 
1164    Input Parameters:
1165 .  pc - the preconditioner context
1166 
1167 
1168    Options Database Key:
1169 .  -pc_gamg_reuse_interpolation
1170 
1171    Level: intermediate
1172 
1173    Concepts: Unstructured multrigrid preconditioner
1174 
1175 .seealso: ()
1176 @*/
1177 PetscErrorCode PCGAMGSetReuseProl(PC pc, PetscBool n)
1178 {
1179   PetscErrorCode ierr;
1180 
1181   PetscFunctionBegin;
1182   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1183   ierr = PetscTryMethod(pc,"PCGAMGSetReuseProl_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1184   PetscFunctionReturn(0);
1185 }
1186 
1187 #undef __FUNCT__
1188 #define __FUNCT__ "PCGAMGSetReuseProl_GAMG"
1189 static PetscErrorCode PCGAMGSetReuseProl_GAMG(PC pc, PetscBool n)
1190 {
1191   PC_MG   *mg      = (PC_MG*)pc->data;
1192   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1193 
1194   PetscFunctionBegin;
1195   pc_gamg->reuse_prol = n;
1196   PetscFunctionReturn(0);
1197 }
1198 
1199 #undef __FUNCT__
1200 #define __FUNCT__ "PCGAMGSetUseASMAggs"
1201 /*@
1202    PCGAMGSetUseASMAggs -
1203 
1204    Collective on PC
1205 
1206    Input Parameters:
1207 .  pc - the preconditioner context
1208 
1209 
1210    Options Database Key:
1211 .  -pc_gamg_use_agg_gasm
1212 
1213    Level: intermediate
1214 
1215    Concepts: Unstructured multrigrid preconditioner
1216 
1217 .seealso: ()
1218 @*/
1219 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1220 {
1221   PetscErrorCode ierr;
1222 
1223   PetscFunctionBegin;
1224   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1225   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1226   PetscFunctionReturn(0);
1227 }
1228 
1229 #undef __FUNCT__
1230 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
1231 static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
1232 {
1233   PC_MG   *mg      = (PC_MG*)pc->data;
1234   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1235 
1236   PetscFunctionBegin;
1237   pc_gamg->use_aggs_in_gasm = n;
1238   PetscFunctionReturn(0);
1239 }
1240 
1241 #undef __FUNCT__
1242 #define __FUNCT__ "PCGAMGSetNlevels"
1243 /*@
1244    PCGAMGSetNlevels -
1245 
1246    Not collective on PC
1247 
1248    Input Parameters:
1249 .  pc - the preconditioner context
1250 
1251 
1252    Options Database Key:
1253 .  -pc_mg_levels
1254 
1255    Level: intermediate
1256 
1257    Concepts: Unstructured multrigrid preconditioner
1258 
1259 .seealso: ()
1260 @*/
1261 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1262 {
1263   PetscErrorCode ierr;
1264 
1265   PetscFunctionBegin;
1266   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1267   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1268   PetscFunctionReturn(0);
1269 }
1270 
1271 #undef __FUNCT__
1272 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
1273 static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
1274 {
1275   PC_MG   *mg      = (PC_MG*)pc->data;
1276   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1277 
1278   PetscFunctionBegin;
1279   pc_gamg->Nlevels = n;
1280   PetscFunctionReturn(0);
1281 }
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 #undef __FUNCT__
1314 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
1315 static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
1316 {
1317   PC_MG   *mg      = (PC_MG*)pc->data;
1318   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1319 
1320   PetscFunctionBegin;
1321   pc_gamg->threshold = n;
1322   PetscFunctionReturn(0);
1323 }
1324 
1325 #undef __FUNCT__
1326 #define __FUNCT__ "PCGAMGSetType"
1327 /*@
1328    PCGAMGSetType - Set solution method - calls sub create method
1329 
1330    Collective on PC
1331 
1332    Input Parameters:
1333 .  pc - the preconditioner context
1334 
1335 
1336    Options Database Key:
1337 .  -pc_gamg_type
1338 
1339    Level: intermediate
1340 
1341    Concepts: Unstructured multrigrid preconditioner
1342 
1343 .seealso: ()
1344 @*/
1345 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1346 {
1347   PetscErrorCode ierr;
1348 
1349   PetscFunctionBegin;
1350   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1351   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1352   PetscFunctionReturn(0);
1353 }
1354 
1355 #undef __FUNCT__
1356 #define __FUNCT__ "PCGAMGSetType_GAMG"
1357 static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
1358 {
1359   PetscErrorCode ierr,(*r)(PC);
1360   PC_MG          *mg      = (PC_MG*)pc->data;
1361   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1362 
1363   PetscFunctionBegin;
1364   ierr = PetscFunctionListFind(GAMGList,type,&r);CHKERRQ(ierr);
1365   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
1366   if (pc_gamg->ops->destroy) {
1367     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1368     ierr = PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));CHKERRQ(ierr);
1369   }
1370   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1371   ierr = PetscStrallocpy(type,&pc_gamg->gamg_type_name);CHKERRQ(ierr);
1372   ierr = (*r)(pc);CHKERRQ(ierr);
1373   PetscFunctionReturn(0);
1374 }
1375 
1376 #undef __FUNCT__
1377 #define __FUNCT__ "PCSetFromOptions_GAMG"
1378 PetscErrorCode PCSetFromOptions_GAMG(PC pc)
1379 {
1380   PetscErrorCode ierr;
1381   PC_MG          *mg      = (PC_MG*)pc->data;
1382   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1383   PetscBool      flag;
1384   PetscInt       two   = 2;
1385   MPI_Comm       comm;
1386 
1387   PetscFunctionBegin;
1388   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1389   ierr = PetscOptionsHead("GAMG options");CHKERRQ(ierr);
1390   {
1391     /* -pc_gamg_type */
1392     {
1393       char tname[256] = PCGAMGAGG;
1394       const char *deftype = pc_gamg->gamg_type_name ? pc_gamg->gamg_type_name : tname;
1395       ierr = PetscOptionsList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, tname, tname, sizeof(tname), &flag);CHKERRQ(ierr);
1396       /* call PCCreateGAMG_XYZ */
1397       if (flag || !pc_gamg->gamg_type_name) {
1398         ierr = PCGAMGSetType(pc, flag ? tname : deftype);CHKERRQ(ierr);
1399       }
1400     }
1401     /* -pc_gamg_verbose */
1402     ierr = PetscOptionsInt("-pc_gamg_verbose","Verbose (debugging) output for PCGAMG",
1403                            "none", pc_gamg->verbose,
1404                            &pc_gamg->verbose, NULL);CHKERRQ(ierr);
1405     /* -pc_gamg_repartition */
1406     ierr = PetscOptionsBool("-pc_gamg_repartition",
1407                             "Repartion coarse grids (false)",
1408                             "PCGAMGRepartitioning",
1409                             pc_gamg->repart,
1410                             &pc_gamg->repart,
1411                             &flag);CHKERRQ(ierr);
1412     /* -pc_gamg_reuse_interpolation */
1413     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation",
1414                             "Reuse prolongation operator (true)",
1415                             "PCGAMGReuseProl",
1416                             pc_gamg->reuse_prol,
1417                             &pc_gamg->reuse_prol,
1418                             &flag);CHKERRQ(ierr);
1419     /* -pc_gamg_use_agg_gasm */
1420     ierr = PetscOptionsBool("-pc_gamg_use_agg_gasm",
1421                             "Use aggregation agragates for GASM smoother (false)",
1422                             "PCGAMGUseASMAggs",
1423                             pc_gamg->use_aggs_in_gasm,
1424                             &pc_gamg->use_aggs_in_gasm,
1425                             &flag);CHKERRQ(ierr);
1426     /* -pc_gamg_process_eq_limit */
1427     ierr = PetscOptionsInt("-pc_gamg_process_eq_limit",
1428                            "Limit (goal) on number of equations per process on coarse grids",
1429                            "PCGAMGSetProcEqLim",
1430                            pc_gamg->min_eq_proc,
1431                            &pc_gamg->min_eq_proc,
1432                            &flag);CHKERRQ(ierr);
1433     /* -pc_gamg_coarse_eq_limit */
1434     ierr = PetscOptionsInt("-pc_gamg_coarse_eq_limit",
1435                            "Limit on number of equations for the coarse grid",
1436                            "PCGAMGSetCoarseEqLim",
1437                            pc_gamg->coarse_eq_limit,
1438                            &pc_gamg->coarse_eq_limit,
1439                            &flag);CHKERRQ(ierr);
1440     /* -pc_gamg_threshold */
1441     ierr = PetscOptionsReal("-pc_gamg_threshold",
1442                             "Relative threshold to use for dropping edges in aggregation graph",
1443                             "PCGAMGSetThreshold",
1444                             pc_gamg->threshold,
1445                             &pc_gamg->threshold,
1446                             &flag);CHKERRQ(ierr);
1447     if (flag && pc_gamg->verbose) {
1448       ierr = PetscPrintf(comm,"\t[%d]%s threshold set %e\n",0,__FUNCT__,pc_gamg->threshold);CHKERRQ(ierr);
1449     }
1450     /* -pc_gamg_eigtarget */
1451     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1452     ierr = PetscOptionsInt("-pc_mg_levels",
1453                            "Set number of MG levels",
1454                            "PCGAMGSetNlevels",
1455                            pc_gamg->Nlevels,
1456                            &pc_gamg->Nlevels,
1457                            &flag);CHKERRQ(ierr);
1458 
1459     /* set options for subtype */
1460     if (pc_gamg->ops->setfromoptions) {ierr = (*pc_gamg->ops->setfromoptions)(pc);CHKERRQ(ierr);}
1461   }
1462   ierr = PetscOptionsTail();CHKERRQ(ierr);
1463   PetscFunctionReturn(0);
1464 }
1465 
1466 /* -------------------------------------------------------------------------- */
1467 /*MC
1468      PCGAMG - Geometric algebraic multigrid (AMG) preconditioning framework.
1469        - This is the entry point to GAMG, registered in pcregis.c
1470 
1471    Options Database Keys:
1472    Multigrid options(inherited)
1473 +  -pc_mg_cycles <1>: 1 for V cycle, 2 for W-cycle (PCMGSetCycleType)
1474 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
1475 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
1476 -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade
1477 
1478   Level: intermediate
1479 
1480   Concepts: multigrid
1481 
1482 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC, PCMGType,
1483            PCMGSetLevels(), PCMGGetLevels(), PCMGSetType(), PCMGSetCycleType(), PCMGSetNumberSmoothDown(),
1484            PCMGSetNumberSmoothUp(), PCMGGetCoarseSolve(), PCMGSetResidual(), PCMGSetInterpolation(),
1485            PCMGSetRestriction(), PCMGGetSmoother(), PCMGGetSmootherUp(), PCMGGetSmootherDown(),
1486            PCMGSetCyclesOnLevel(), PCMGSetRhs(), PCMGSetX(), PCMGSetR()
1487 M*/
1488 
1489 #undef __FUNCT__
1490 #define __FUNCT__ "PCCreate_GAMG"
1491 PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
1492 {
1493   PetscErrorCode ierr;
1494   PC_GAMG        *pc_gamg;
1495   PC_MG          *mg;
1496 #if defined PETSC_GAMG_USE_LOG
1497   static long count = 0;
1498 #endif
1499 
1500   PetscFunctionBegin;
1501   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1502   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr); /* calls PCCreate_MG() and MGCreate_Private() */
1503   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1504 
1505   /* create a supporting struct and attach it to pc */
1506   ierr         = PetscNewLog(pc, PC_GAMG, &pc_gamg);CHKERRQ(ierr);
1507   mg           = (PC_MG*)pc->data;
1508   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally */
1509   mg->innerctx = pc_gamg;
1510 
1511   ierr = PetscNewLog(pc,struct _PCGAMGOps,&pc_gamg->ops);CHKERRQ(ierr);
1512 
1513   pc_gamg->setup_count = 0;
1514   /* these should be in subctx but repartitioning needs simple arrays */
1515   pc_gamg->data_sz = 0;
1516   pc_gamg->data    = 0;
1517 
1518   /* register AMG type */
1519 #if !defined(PETSC_USE_DYNAMIC_LIBRARIES)
1520   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1521 #endif
1522 
1523   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
1524   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
1525   pc->ops->setup          = PCSetUp_GAMG;
1526   pc->ops->reset          = PCReset_GAMG;
1527   pc->ops->destroy        = PCDestroy_GAMG;
1528 
1529   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1530   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1531   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1532   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseProl_C",PCGAMGSetReuseProl_GAMG);CHKERRQ(ierr);
1533   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1534   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1535   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);CHKERRQ(ierr);
1536   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);CHKERRQ(ierr);
1537   pc_gamg->repart           = PETSC_FALSE;
1538   pc_gamg->reuse_prol       = PETSC_FALSE;
1539   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
1540   pc_gamg->min_eq_proc      = 50;
1541   pc_gamg->coarse_eq_limit  = 800;
1542   pc_gamg->threshold        = 0.;
1543   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
1544   pc_gamg->verbose          = 0;
1545   pc_gamg->emax_id          = -1;
1546   pc_gamg->eigtarget[0]     = 0.05;
1547   pc_gamg->eigtarget[1]     = 1.05;
1548 
1549   /* private events */
1550 #if defined PETSC_GAMG_USE_LOG
1551   if (count++ == 0) {
1552     ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1553     ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
1554     /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
1555     /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
1556     /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
1557     ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1558     ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1559     ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1560     ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1561     ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1562     ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1563     ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1564     ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1565     ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1566     ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1567     ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1568     ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1569 
1570     /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
1571     /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
1572     /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
1573     /* create timer stages */
1574 #if defined GAMG_STAGES
1575     {
1576       char     str[32];
1577       PetscInt lidx;
1578       sprintf(str,"MG Level %d (finest)",0);
1579       ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1580       for (lidx=1; lidx<9; lidx++) {
1581         sprintf(str,"MG Level %d",lidx);
1582         ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1583       }
1584     }
1585 #endif
1586   }
1587 #endif
1588 
1589   PetscFunctionReturn(0);
1590 }
1591 
1592 #undef __FUNCT__
1593 #define __FUNCT__ "PCGAMGInitializePackage"
1594 /*@C
1595  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
1596  from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
1597  when using static libraries.
1598 
1599  Level: developer
1600 
1601  .keywords: PC, PCGAMG, initialize, package
1602  .seealso: PetscInitialize()
1603 @*/
1604 PetscErrorCode PCGAMGInitializePackage(void)
1605 {
1606   PetscErrorCode ierr;
1607 
1608   PetscFunctionBegin;
1609   if (PCGAMGPackageInitialized) PetscFunctionReturn(0);
1610   PCGAMGPackageInitialized = PETSC_TRUE;
1611   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);CHKERRQ(ierr);
1612   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);CHKERRQ(ierr);
1613   ierr = PetscRegisterFinalize(PCGAMGFinalizePackage);CHKERRQ(ierr);
1614 
1615   /* general events */
1616 #if defined PETSC_USE_LOG
1617   ierr = PetscLogEventRegister("PCGAMGgraph_AGG", 0, &PC_GAMGGgraph_AGG);CHKERRQ(ierr);
1618   ierr = PetscLogEventRegister("PCGAMGgraph_GEO", PC_CLASSID, &PC_GAMGGgraph_GEO);CHKERRQ(ierr);
1619   ierr = PetscLogEventRegister("PCGAMGcoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1620   ierr = PetscLogEventRegister("PCGAMGcoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1621   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1622   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1623   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptprol_AGG);CHKERRQ(ierr);
1624   ierr = PetscLogEventRegister("GAMGKKTProl_AGG", PC_CLASSID, &PC_GAMGKKTProl_AGG);CHKERRQ(ierr);
1625 #endif
1626 
1627   PetscFunctionReturn(0);
1628 }
1629 
1630 #undef __FUNCT__
1631 #define __FUNCT__ "PCGAMGFinalizePackage"
1632 /*@C
1633  PCGAMGFinalizePackage - This function destroys everything in the PCGAMG package. It is
1634  called from PetscFinalize().
1635 
1636  Level: developer
1637 
1638  .keywords: Petsc, destroy, package
1639  .seealso: PetscFinalize()
1640 @*/
1641 PetscErrorCode PCGAMGFinalizePackage(void)
1642 {
1643   PetscErrorCode ierr;
1644 
1645   PetscFunctionBegin;
1646   PCGAMGPackageInitialized = PETSC_FALSE;
1647   ierr = PetscFunctionListDestroy(&GAMGList);CHKERRQ(ierr);
1648   PetscFunctionReturn(0);
1649 }
1650