xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision 0a7e80ddf00b85a8bec408344d0bbd42e7f7dbd2)
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 static PetscBool PCGAMGPackageInitialized;
32 
33 /* ----------------------------------------------------------------------------- */
34 #undef __FUNCT__
35 #define __FUNCT__ "PCReset_GAMG"
36 PetscErrorCode PCReset_GAMG(PC pc)
37 {
38   PetscErrorCode ierr;
39   PC_MG          *mg      = (PC_MG*)pc->data;
40   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
41 
42   PetscFunctionBegin;
43   if (pc_gamg->data) { /* this should not happen, cleaned up in SetUp */
44     PetscPrintf(PetscObjectComm((PetscObject)pc),"***[%d]%s this should not happen, cleaned up in SetUp\n",0,__FUNCT__);
45     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
46   }
47   pc_gamg->data = NULL; pc_gamg->data_sz = 0;
48 
49   if (pc_gamg->orig_data) {
50     ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
51   }
52   PetscFunctionReturn(0);
53 }
54 
55 /* private 2x2 Mat Nest for Stokes */
56 typedef struct {
57   Mat A11,A21,A12,Amat;
58   IS  prim_is,constr_is;
59 } GAMGKKTMat;
60 
61 #undef __FUNCT__
62 #define __FUNCT__ "GAMGKKTMatCreate"
63 static PetscErrorCode GAMGKKTMatCreate(Mat A, PetscBool iskkt, GAMGKKTMat *out)
64 {
65   PetscFunctionBegin;
66   out->Amat = A;
67   if (iskkt) {
68     PetscErrorCode ierr;
69     IS             is_constraint, is_prime;
70     PetscInt       nmin,nmax;
71 
72     ierr = MatGetOwnershipRange(A, &nmin, &nmax);CHKERRQ(ierr);
73     ierr = MatFindZeroDiagonals(A, &is_constraint);CHKERRQ(ierr);
74     ierr = ISComplement(is_constraint, nmin, nmax, &is_prime);CHKERRQ(ierr);
75 
76     out->prim_is   = is_prime;
77     out->constr_is = is_constraint;
78 
79     ierr = MatGetSubMatrix(A, is_prime, is_prime,      MAT_INITIAL_MATRIX, &out->A11);CHKERRQ(ierr);
80     ierr = MatGetSubMatrix(A, is_prime, is_constraint, MAT_INITIAL_MATRIX, &out->A12);CHKERRQ(ierr);
81     ierr = MatGetSubMatrix(A, is_constraint, is_prime, MAT_INITIAL_MATRIX, &out->A21);CHKERRQ(ierr);
82   } else {
83     out->A11       = A;
84     out->A21       = NULL;
85     out->A12       = NULL;
86     out->prim_is   = NULL;
87     out->constr_is = NULL;
88   }
89   PetscFunctionReturn(0);
90 }
91 
92 #undef __FUNCT__
93 #define __FUNCT__ "GAMGKKTMatDestroy"
94 static PetscErrorCode GAMGKKTMatDestroy(GAMGKKTMat *mat)
95 {
96   PetscErrorCode ierr;
97 
98   PetscFunctionBegin;
99   if (mat->A11 && mat->A11 != mat->Amat) {
100     ierr = MatDestroy(&mat->A11);CHKERRQ(ierr);
101   }
102   ierr = MatDestroy(&mat->A21);CHKERRQ(ierr);
103   ierr = MatDestroy(&mat->A12);CHKERRQ(ierr);
104 
105   ierr = ISDestroy(&mat->prim_is);CHKERRQ(ierr);
106   ierr = ISDestroy(&mat->constr_is);CHKERRQ(ierr);
107   PetscFunctionReturn(0);
108 }
109 
110 /* -------------------------------------------------------------------------- */
111 /*
112    createLevel: create coarse op with RAP.  repartition and/or reduce number
113      of active processors.
114 
115    Input Parameter:
116    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
117           'pc_gamg->data_sz' are changed via repartitioning/reduction.
118    . Amat_fine - matrix on this fine (k) level
119    . cr_bs - coarse block size
120    . isLast -
121    . stokes -
122    In/Output Parameter:
123    . a_P_inout - prolongation operator to the next level (k-->k-1)
124    . a_nactive_proc - number of active procs
125    Output Parameter:
126    . a_Amat_crs - coarse matrix that is created (k-1)
127 */
128 
129 #undef __FUNCT__
130 #define __FUNCT__ "createLevel"
131 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)
132 {
133   PetscErrorCode  ierr;
134   PC_MG           *mg         = (PC_MG*)pc->data;
135   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
136   const PetscBool repart      = pc_gamg->repart;
137   const PetscInt  min_eq_proc = pc_gamg->min_eq_proc, coarse_max = pc_gamg->coarse_eq_limit;
138   Mat             Cmat,Pold=*a_P_inout;
139   MPI_Comm        comm;
140   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
141   PetscInt        ncrs_eq,ncrs_prim,f_bs;
142 
143   PetscFunctionBegin;
144   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
145   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
146   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
147   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
148   /* RAP */
149   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
150 
151   /* set 'ncrs_prim' (nodes), 'ncrs_eq' (equations)*/
152   ncrs_prim = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
153   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);
154   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
155 
156   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
157   {
158     PetscInt ncrs_eq_glob;
159     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
160     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
161     if (new_size == 0 || ncrs_eq_glob < coarse_max) new_size = 1;
162     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
163     if (isLast) new_size = 1;
164   }
165 
166   if (!repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
167   else {
168     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
169     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_prim_new,ncrs_eq_new,nloc_old;
170     IS             is_eq_newproc,is_eq_newproc_prim,is_eq_num,is_eq_num_prim,isscat,new_eq_indices;
171     VecScatter     vecscat;
172     PetscScalar    *array;
173     Vec            src_crd, dest_crd;
174 
175     nloc_old = ncrs_eq/cr_bs;
176     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);
177 #if defined PETSC_GAMG_USE_LOG
178     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
179 #endif
180     /* make 'is_eq_newproc' */
181     ierr = PetscMalloc(size*sizeof(PetscInt), &counts);CHKERRQ(ierr);
182     if (repart && !stokes) {
183       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
184       Mat adj;
185 
186       if (pc_gamg->verbose>0) {
187         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);
188         else {
189           PetscInt n;
190           ierr = MPI_Allreduce(&ncrs_eq, &n, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
191           PetscPrintf(comm,"\t[%d]%s repartition: size (active): %d --> %d, neq = %d\n",rank,__FUNCT__,*a_nactive_proc,new_size,n);
192         }
193       }
194 
195       /* get 'adj' */
196       if (cr_bs == 1) {
197         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
198       } else {
199         /* make a scalar matrix to partition (no Stokes here) */
200         Mat               tMat;
201         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
202         const PetscScalar *vals;
203         const PetscInt    *idx;
204         PetscInt          *d_nnz, *o_nnz, M, N;
205         static PetscInt   llev = 0;
206 
207         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &d_nnz);CHKERRQ(ierr);
208         ierr = PetscMalloc(ncrs_prim*sizeof(PetscInt), &o_nnz);CHKERRQ(ierr);
209         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
210         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
211         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
212           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
213           d_nnz[jj] = ncols/cr_bs;
214           o_nnz[jj] = ncols/cr_bs;
215           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
216           if (d_nnz[jj] > ncrs_prim) d_nnz[jj] = ncrs_prim;
217           if (o_nnz[jj] > (M/cr_bs-ncrs_prim)) o_nnz[jj] = M/cr_bs-ncrs_prim;
218         }
219 
220         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
221         ierr = MatSetSizes(tMat, ncrs_prim, ncrs_prim,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
222         ierr = MatSetType(tMat,MATAIJ);CHKERRQ(ierr);
223         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
224         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
225         ierr = PetscFree(d_nnz);CHKERRQ(ierr);
226         ierr = PetscFree(o_nnz);CHKERRQ(ierr);
227 
228         for (ii = Istart_crs; ii < Iend_crs; ii++) {
229           PetscInt dest_row = ii/cr_bs;
230           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
231           for (jj = 0; jj < ncols; jj++) {
232             PetscInt    dest_col = idx[jj]/cr_bs;
233             PetscScalar v        = 1.0;
234             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
235           }
236           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
237         }
238         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
239         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
240 
241         if (llev++ == -1) {
242           PetscViewer viewer; char fname[32];
243           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
244           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
245           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
246           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
247         }
248 
249         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
250 
251         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
252       } /* create 'adj' */
253 
254       { /* partition: get newproc_idx */
255         char            prefix[256];
256         const char      *pcpre;
257         const PetscInt  *is_idx;
258         MatPartitioning mpart;
259         IS              proc_is;
260         PetscInt        targetPE;
261 
262         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
263         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
264         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
265         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
266         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
267         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
268         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
269         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
270         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
271 
272         /* collect IS info */
273         ierr     = PetscMalloc(ncrs_eq*sizeof(PetscInt), &newproc_idx);CHKERRQ(ierr);
274         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
275         targetPE = 1; /* bring to "front" of machine */
276         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
277         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
278           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
279             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
280           }
281         }
282         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
283         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
284       }
285       ierr = MatDestroy(&adj);CHKERRQ(ierr);
286 
287       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
288       if (newproc_idx != 0) {
289         ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
290       }
291     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
292 
293       PetscInt rfactor,targetPE;
294       /* find factor */
295       if (new_size == 1) rfactor = size; /* easy */
296       else {
297         PetscReal best_fact = 0.;
298         jj = -1;
299         for (kk = 1 ; kk <= size ; kk++) {
300           if (size%kk==0) { /* a candidate */
301             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
302             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
303             if (fact > best_fact) {
304               best_fact = fact; jj = kk;
305             }
306           }
307         }
308         if (jj != -1) rfactor = jj;
309         else rfactor = 1; /* does this happen .. a prime */
310       }
311       new_size = size/rfactor;
312 
313       if (new_size==nactive) {
314         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
315         ierr        = PetscFree(counts);CHKERRQ(ierr);
316         if (pc_gamg->verbose>0) {
317           PetscPrintf(comm,"\t[%d]%s aggregate processors noop: new_size=%d, neq(loc)=%d\n",rank,__FUNCT__,new_size,ncrs_eq);
318         }
319         PetscFunctionReturn(0);
320       }
321 
322       if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s number of equations (loc) %d with simple aggregation\n",rank,__FUNCT__,ncrs_eq);
323       targetPE = rank/rfactor;
324       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
325 
326       if (stokes) {
327         ierr = ISCreateStride(comm, ncrs_prim*cr_bs, targetPE, 0, &is_eq_newproc_prim);CHKERRQ(ierr);
328       }
329     } /* end simple 'is_eq_newproc' */
330 
331     /*
332      Create an index set from the is_eq_newproc index set to indicate the mapping TO
333      */
334     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
335     if (stokes) {
336       ierr = ISPartitioningToNumbering(is_eq_newproc_prim, &is_eq_num_prim);CHKERRQ(ierr);
337     } else is_eq_num_prim = is_eq_num;
338     /*
339       Determine how many equations/vertices are assigned to each processor
340      */
341     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
342     ncrs_eq_new = counts[rank];
343     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
344     if (stokes) {
345       ierr          = ISPartitioningCount(is_eq_newproc_prim, size, counts);CHKERRQ(ierr);
346       ierr          = ISDestroy(&is_eq_newproc_prim);CHKERRQ(ierr);
347       ncrs_prim_new = counts[rank]/cr_bs; /* nodes */
348     } else ncrs_prim_new = ncrs_eq_new/cr_bs; /* eqs */
349 
350     ierr = PetscFree(counts);CHKERRQ(ierr);
351 #if defined PETSC_GAMG_USE_LOG
352     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
353 #endif
354 
355     /* move data (for primal equations only) */
356     /* Create a vector to contain the newly ordered element information */
357     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
358     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_prim_new, PETSC_DECIDE);CHKERRQ(ierr);
359     ierr = VecSetFromOptions(dest_crd);CHKERRQ(ierr); /* this is needed! */
360     /*
361      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
362      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
363      */
364     ierr = PetscMalloc((ncrs_prim*node_data_sz)*sizeof(PetscInt), &tidx);CHKERRQ(ierr);
365     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
366     for (ii=0,jj=0; ii<ncrs_prim; ii++) {
367       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
368       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
369     }
370     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
371     ierr = ISCreateGeneral(comm, node_data_sz*ncrs_prim, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
372     ierr = PetscFree(tidx);CHKERRQ(ierr);
373     /*
374      Create a vector to contain the original vertex information for each element
375      */
376     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs_prim, &src_crd);CHKERRQ(ierr);
377     for (jj=0; jj<ndata_cols; jj++) {
378       const PetscInt stride0=ncrs_prim*pc_gamg->data_cell_rows;
379       for (ii=0; ii<ncrs_prim; ii++) {
380         for (kk=0; kk<ndata_rows; kk++) {
381           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
382           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
383           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
384         }
385       }
386     }
387     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
388     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
389     /*
390       Scatter the element vertex information (still in the original vertex ordering)
391       to the correct processor
392     */
393     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
394     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
395     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
396     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
397     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
398     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
399     /*
400       Put the element vertex data into a new allocation of the gdata->ele
401     */
402     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
403     ierr = PetscMalloc(node_data_sz*ncrs_prim_new*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
404 
405     pc_gamg->data_sz = node_data_sz*ncrs_prim_new;
406     strideNew        = ncrs_prim_new*ndata_rows;
407 
408     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
409     for (jj=0; jj<ndata_cols; jj++) {
410       for (ii=0; ii<ncrs_prim_new; ii++) {
411         for (kk=0; kk<ndata_rows; kk++) {
412           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
413           pc_gamg->data[ix] = PetscRealPart(array[jx]);
414         }
415       }
416     }
417     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
418     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
419 
420     /* move A and P (columns) with new layout */
421 #if defined PETSC_GAMG_USE_LOG
422     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
423 #endif
424 
425     /*
426       Invert for MatGetSubMatrix
427     */
428     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
429     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
430     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
431     if (is_eq_num != is_eq_num_prim) {
432       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
433     }
434     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
435 #if defined PETSC_GAMG_USE_LOG
436     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
437     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
438 #endif
439     /* 'a_Amat_crs' output */
440     {
441       Mat mat;
442       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
443       *a_Amat_crs = mat;
444 
445       if (!PETSC_TRUE) {
446         PetscInt cbs, rbs;
447         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
448         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
449         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
450         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);
451       }
452     }
453     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
454 
455 #if defined PETSC_GAMG_USE_LOG
456     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
457 #endif
458     /* prolongator */
459     {
460       IS       findices;
461       PetscInt Istart,Iend;
462       Mat      Pnew;
463       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
464 #if defined PETSC_GAMG_USE_LOG
465       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
466 #endif
467       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
468       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
469       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
470       ierr = ISDestroy(&findices);CHKERRQ(ierr);
471 
472       if (!PETSC_TRUE) {
473         PetscInt cbs, rbs;
474         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
475         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
476         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
477         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
478       }
479 #if defined PETSC_GAMG_USE_LOG
480       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
481 #endif
482       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
483 
484       /* output - repartitioned */
485       *a_P_inout = Pnew;
486     }
487     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
488 
489     *a_nactive_proc = new_size; /* output */
490   }
491 
492   /* outout matrix data */
493   if (!PETSC_TRUE) {
494     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
495     if (llev==0) {
496       sprintf(fname,"Cmat_%d.m",llev++);
497       PetscViewerASCIIOpen(comm,fname,&viewer);
498       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
499       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
500       ierr = PetscViewerDestroy(&viewer);
501     }
502     sprintf(fname,"Cmat_%d.m",llev++);
503     PetscViewerASCIIOpen(comm,fname,&viewer);
504     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
505     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
506     ierr = PetscViewerDestroy(&viewer);
507   }
508   PetscFunctionReturn(0);
509 }
510 
511 /* -------------------------------------------------------------------------- */
512 /*
513    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
514                     by setting data structures and options.
515 
516    Input Parameter:
517 .  pc - the preconditioner context
518 
519    Application Interface Routine: PCSetUp()
520 
521    Notes:
522    The interface routine PCSetUp() is not usually called directly by
523    the user, but instead is called by PCApply() if necessary.
524 */
525 #undef __FUNCT__
526 #define __FUNCT__ "PCSetUp_GAMG"
527 PetscErrorCode PCSetUp_GAMG(PC pc)
528 {
529   PetscErrorCode ierr;
530   PC_MG          *mg      = (PC_MG*)pc->data;
531   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
532   Mat            Pmat     = pc->pmat;
533   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
534   MPI_Comm       comm;
535   PetscMPIInt    rank,size,nactivepe;
536   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
537   PetscReal      emaxs[GAMG_MAXLEVELS];
538   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
539   GAMGKKTMat     kktMatsArr[GAMG_MAXLEVELS];
540   PetscLogDouble nnz0=0.,nnztot=0.;
541   MatInfo        info;
542   PetscBool      stokes = PETSC_FALSE, redo_mesh_setup = (PetscBool)(!pc_gamg->reuse_prol);
543 
544   PetscFunctionBegin;
545   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
546   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
547   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
548 
549   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);
550 
551   if (pc_gamg->setup_count++ > 0) {
552     if (redo_mesh_setup) {
553       /* reset everything */
554       ierr = PCReset_MG(pc);CHKERRQ(ierr);
555       pc->setupcalled = 0;
556     } else {
557       PC_MG_Levels **mglevels = mg->levels;
558       /* just do Galerkin grids */
559       Mat          B,dA,dB;
560 
561      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
562       if (pc_gamg->Nlevels > 1) {
563         /* currently only handle case where mat and pmat are the same on coarser levels */
564         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB,NULL);CHKERRQ(ierr);
565         /* (re)set to get dirty flag */
566         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
567 
568         for (level=pc_gamg->Nlevels-2; level>=0; level--) {
569           /* the first time through the matrix structure has changed from repartitioning */
570           if (pc_gamg->setup_count==2 && (pc_gamg->repart || level==0)) {
571             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
572             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
573 
574             mglevels[level]->A = B;
575           } else {
576             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B,NULL);CHKERRQ(ierr);
577             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
578           }
579           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
580           dB   = B;
581         }
582       }
583 
584       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
585 
586       /* PCSetUp_MG seems to insists on setting this to GMRES */
587       ierr = KSPSetType(mglevels[0]->smoothd, KSPPREONLY);CHKERRQ(ierr);
588       PetscFunctionReturn(0);
589     }
590   }
591 
592   ierr = PetscOptionsGetBool(((PetscObject)pc)->prefix,"-pc_fieldsplit_detect_saddle_point",&stokes,NULL);CHKERRQ(ierr);
593 
594   ierr = GAMGKKTMatCreate(Pmat, stokes, &kktMatsArr[0]);CHKERRQ(ierr);
595 
596   if (!pc_gamg->data) {
597     if (pc_gamg->orig_data) {
598       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
599       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
600 
601       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
602       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
603       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;
604 
605       ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
606       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
607     } else {
608       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
609       if (stokes) SETERRQ(comm,PETSC_ERR_PLIB,"Need data (eg, PCSetCoordinates) for Stokes problems");
610       ierr = pc_gamg->ops->createdefaultdata(pc, kktMatsArr[0].A11);CHKERRQ(ierr);
611     }
612   }
613 
614   /* cache original data for reuse */
615   if (!pc_gamg->orig_data && redo_mesh_setup) {
616     ierr = PetscMalloc(pc_gamg->data_sz*sizeof(PetscReal), &pc_gamg->orig_data);CHKERRQ(ierr);
617     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
618     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
619     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
620   }
621 
622   /* get basic dims */
623   if (stokes) bs = pc_gamg->data_cell_rows; /* this is agg-mg specific */
624   else {
625     ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
626   }
627 
628   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
629   if (pc_gamg->verbose) {
630     PetscInt NN = M;
631     if (pc_gamg->verbose==1) {
632       ierr =  MatGetInfo(Pmat,MAT_LOCAL,&info);CHKERRQ(ierr);
633       ierr = MatGetLocalSize(Pmat, &NN, &qq);CHKERRQ(ierr);
634     } else {
635       ierr = MatGetInfo(Pmat,MAT_GLOBAL_SUM,&info);CHKERRQ(ierr);
636     }
637     nnz0   = info.nz_used;
638     nnztot = info.nz_used;
639     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",
640                          rank,__FUNCT__,0,M,pc_gamg->data_cell_rows,pc_gamg->data_cell_cols,
641                          (int)(nnz0/(PetscReal)NN),size);CHKERRQ(ierr);
642   }
643 
644   /* Get A_i and R_i */
645   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
646        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);  /* && (size==1 || nactivepe>1); */
647        level++) {
648     level1 = level + 1;
649 #if defined PETSC_GAMG_USE_LOG
650     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
651 #if (defined GAMG_STAGES)
652     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
653 #endif
654 #endif
655     /* deal with Stokes, get sub matrices */
656     if (level > 0) {
657       ierr = GAMGKKTMatCreate(Aarr[level], stokes, &kktMatsArr[level]);CHKERRQ(ierr);
658     }
659     { /* construct prolongator */
660       Mat              Gmat;
661       PetscCoarsenData *agg_lists;
662       Mat              Prol11,Prol22;
663 
664       ierr = pc_gamg->ops->graph(pc,kktMatsArr[level].A11, &Gmat);CHKERRQ(ierr);
665       ierr = pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
666       ierr = pc_gamg->ops->prolongator(pc, kktMatsArr[level].A11, Gmat, agg_lists, &Prol11);CHKERRQ(ierr);
667 
668       /* could have failed to create new level */
669       if (Prol11) {
670         /* get new block size of coarse matrices */
671         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
672 
673         if (stokes) {
674           if (!pc_gamg->ops->formkktprol) SETERRQ(comm,PETSC_ERR_USER,"Stokes not supportd by AMG method.");
675           /* R A12 == (T = A21 P)';  G = T' T; coarsen G; form plain agg with G */
676           ierr = pc_gamg->ops->formkktprol(pc, Prol11, kktMatsArr[level].A21, &Prol22);CHKERRQ(ierr);
677         }
678 
679         if (pc_gamg->ops->optprol) {
680           /* smooth */
681           ierr = pc_gamg->ops->optprol(pc, kktMatsArr[level].A11, &Prol11);CHKERRQ(ierr);
682         }
683 
684         if (stokes) {
685           IS  is_row[2];
686           Mat a[4];
687 
688           is_row[0] = kktMatsArr[level].prim_is; is_row[1] = kktMatsArr[level].constr_is;
689           a[0]      = Prol11; a[1] = NULL; a[2] = NULL; a[3] = Prol22;
690           ierr      = MatCreateNest(comm,2,is_row, 2, is_row, a, &Parr[level1]);CHKERRQ(ierr);
691         } else Parr[level1] = Prol11;
692       } else Parr[level1] = NULL;
693 
694       if (pc_gamg->use_aggs_in_gasm) {
695         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
696       }
697 
698       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
699       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
700     } /* construct prolongator scope */
701 #if defined PETSC_GAMG_USE_LOG
702     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
703 #endif
704     /* cache eigen estimate */
705     if (pc_gamg->emax_id != -1) {
706       PetscBool flag;
707       ierr = PetscObjectComposedDataGetReal((PetscObject)kktMatsArr[level].A11, pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
708       if (!flag) emaxs[level] = -1.;
709     } else emaxs[level] = -1.;
710     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
711     if (!Parr[level1]) {
712       if (pc_gamg->verbose) {
713         ierr =  PetscPrintf(comm,"\t[%d]%s stop gridding, level %d\n",rank,__FUNCT__,level);CHKERRQ(ierr);
714       }
715       break;
716     }
717 #if defined PETSC_GAMG_USE_LOG
718     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
719 #endif
720 
721     ierr = createLevel(pc, Aarr[level], bs, (PetscBool)(level==pc_gamg->Nlevels-2),
722                        stokes, &Parr[level1], &Aarr[level1], &nactivepe);CHKERRQ(ierr);
723 
724 #if defined PETSC_GAMG_USE_LOG
725     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
726 #endif
727     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
728 
729     if (pc_gamg->verbose > 0) {
730       PetscInt NN = M;
731       if (pc_gamg->verbose==1) {
732         ierr = MatGetInfo(Aarr[level1],MAT_LOCAL,&info);CHKERRQ(ierr);
733         ierr = MatGetLocalSize(Aarr[level1], &NN, &qq);CHKERRQ(ierr);
734       } else {
735         ierr = MatGetInfo(Aarr[level1], MAT_GLOBAL_SUM, &info);CHKERRQ(ierr);
736       }
737 
738       nnztot += info.nz_used;
739       ierr    = PetscPrintf(comm,"\t\t[%d]%s %d) N=%d, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",
740                             rank,__FUNCT__,(int)level1,M,pc_gamg->data_cell_cols,
741                             (int)(info.nz_used/(PetscReal)NN), nactivepe);CHKERRQ(ierr);
742     }
743 
744     /* stop if one node -- could pull back for singular problems */
745     if (M/pc_gamg->data_cell_cols < 2) {
746       level++;
747       break;
748     }
749 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
750     ierr = PetscLogStagePop();CHKERRQ(ierr);
751 #endif
752   } /* levels */
753 
754   if (pc_gamg->data) {
755     ierr          = PetscFree(pc_gamg->data);CHKERRQ(ierr);
756     pc_gamg->data = NULL;
757   }
758 
759   if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s %d levels, grid complexity = %g\n",0,__FUNCT__,level+1,nnztot/nnz0);
760   pc_gamg->Nlevels = level + 1;
761   fine_level       = level;
762   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
763 
764   /* simple setup */
765   if (!PETSC_TRUE) {
766     PC_MG_Levels **mglevels = mg->levels;
767     for (lidx=0,level=pc_gamg->Nlevels-1;
768          lidx<fine_level;
769          lidx++, level--) {
770       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
771       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
772       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
773       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
774     }
775     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
776 
777     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
778   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
779     /* set default smoothers & set operators */
780     for (lidx = 1, level = pc_gamg->Nlevels-2;
781          lidx <= fine_level;
782          lidx++, level--) {
783       KSP smoother;
784       PC  subpc;
785 
786       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
787       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
788 
789       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
790       /* set ops */
791       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
792       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
793 
794       /* create field split PC, get subsmoother */
795       if (stokes) {
796         KSP      *ksps;
797         PetscInt nn;
798         ierr     = PCFieldSplitSetIS(subpc,"0",kktMatsArr[level].prim_is);CHKERRQ(ierr);
799         ierr     = PCFieldSplitSetIS(subpc,"1",kktMatsArr[level].constr_is);CHKERRQ(ierr);
800         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
801         smoother = ksps[0];
802         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
803         ierr     = PetscFree(ksps);CHKERRQ(ierr);
804       }
805       ierr = GAMGKKTMatDestroy(&kktMatsArr[level]);CHKERRQ(ierr);
806 
807       /* set defaults */
808       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
809 
810       /* override defaults and command line args (!) */
811       if (pc_gamg->use_aggs_in_gasm) {
812         PetscInt sz;
813         IS       *is;
814 
815         sz   = nASMBlocksArr[level];
816         is   = ASMLocalIDsArr[level];
817         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
818         if (sz==0) {
819           IS       is;
820           PetscInt my0,kk;
821           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
822           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
823           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
824           ierr = ISDestroy(&is);CHKERRQ(ierr);
825         } else {
826           PetscInt kk;
827           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
828           for (kk=0; kk<sz; kk++) {
829             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
830           }
831           ierr = PetscFree(is);CHKERRQ(ierr);
832         }
833         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
834 
835         ASMLocalIDsArr[level] = NULL;
836         nASMBlocksArr[level]  = 0;
837         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
838       } else {
839         ierr = PCSetType(subpc, PCJACOBI);CHKERRQ(ierr);
840       }
841     }
842     {
843       /* coarse grid */
844       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
845       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
846       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
847       ierr = KSPSetOperators(smoother, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
848       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
849       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
850       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
851       ierr = PCSetUp(subpc);CHKERRQ(ierr);
852       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
853       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
854       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
855       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
856       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
857       ierr = KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);CHKERRQ(ierr);
858     }
859 
860     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
861     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
862     ierr = PCSetFromOptions_MG(pc);CHKERRQ(ierr);
863     ierr = PetscOptionsEnd();CHKERRQ(ierr);
864     if (mg->galerkin != 2) SETERRQ(comm,PETSC_ERR_USER,"GAMG does Galerkin manually so the -pc_mg_galerkin option must not be used.");
865 
866     /* create cheby smoothers */
867     for (lidx = 1, level = pc_gamg->Nlevels-2;
868          lidx <= fine_level;
869          lidx++, level--) {
870       KSP       smoother;
871       PetscBool flag;
872       PC        subpc;
873 
874       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
875       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
876 
877       /* create field split PC, get subsmoother */
878       if (stokes) {
879         KSP      *ksps;
880         PetscInt nn;
881         ierr     = PCFieldSplitGetSubKSP(subpc,&nn,&ksps);CHKERRQ(ierr);
882         smoother = ksps[0];
883         ierr     = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
884         ierr     = PetscFree(ksps);CHKERRQ(ierr);
885       }
886 
887       /* do my own cheby */
888       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
889       if (flag) {
890         PetscReal emax, emin;
891         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
892         if (flag && emaxs[level] > 0.0) emax=emaxs[level]; /* eigen estimate only for diagnal PC */
893         else { /* eigen estimate 'emax' */
894           KSP eksp;
895           Mat Lmat = Aarr[level];
896           Vec bb, xx;
897 
898           ierr = MatGetVecs(Lmat, &bb, 0);CHKERRQ(ierr);
899           ierr = MatGetVecs(Lmat, &xx, 0);CHKERRQ(ierr);
900           {
901             PetscRandom rctx;
902             ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
903             ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
904             ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
905             ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
906           }
907 
908           /* zeroing out BC rows -- needed for crazy matrices */
909           {
910             PetscInt    Istart,Iend,ncols,jj,Ii;
911             PetscScalar zero = 0.0;
912             ierr = MatGetOwnershipRange(Lmat, &Istart, &Iend);CHKERRQ(ierr);
913             for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
914               ierr = MatGetRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
915               if (ncols <= 1) {
916                 ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
917               }
918               ierr = MatRestoreRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
919             }
920             ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
921             ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
922           }
923 
924           ierr = KSPCreate(comm, &eksp);CHKERRQ(ierr);
925           ierr = KSPSetTolerances(eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10);CHKERRQ(ierr);
926           ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
927           ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
928           ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
929           ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
930 
931           ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
932           ierr = KSPSetOperators(eksp, Lmat, Lmat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
933           ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
934 
935           /* set PC type to be same as smoother */
936           ierr = KSPSetPC(eksp, subpc);CHKERRQ(ierr);
937 
938           /* solve - keep stuff out of logging */
939           ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
940           ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
941           ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
942           ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
943           ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
944 
945           ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
946 
947           ierr = VecDestroy(&xx);CHKERRQ(ierr);
948           ierr = VecDestroy(&bb);CHKERRQ(ierr);
949           ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
950 
951           if (pc_gamg->verbose > 0) {
952             PetscInt N1, tt;
953             ierr = MatGetSize(Aarr[level], &N1, &tt);CHKERRQ(ierr);
954             PetscPrintf(comm,"\t\t\t%s PC setup max eigen=%e min=%e on level %d (N=%d)\n",__FUNCT__,emax,emin,lidx,N1);
955           }
956         }
957         {
958           PetscInt N1, N0;
959           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
960           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
961           /* heuristic - is this crap? */
962           /* emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); */
963           emin  = emax * pc_gamg->eigtarget[0];
964           emax *= pc_gamg->eigtarget[1];
965         }
966         ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
967       } /* setup checby flag */
968     } /* non-coarse levels */
969 
970     /* clean up */
971     for (level=1; level<pc_gamg->Nlevels; level++) {
972       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
973       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
974     }
975 
976     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
977 
978     if (PETSC_TRUE) {
979       KSP smoother;  /* PCSetUp_MG seems to insists on setting this to GMRES on coarse grid */
980       ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
981       ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
982     }
983   } else {
984     KSP smoother;
985     if (pc_gamg->verbose) PetscPrintf(comm,"\t[%d]%s one level solver used (system is seen as DD). Using default solver.\n",rank,__FUNCT__);
986     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
987     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0], SAME_NONZERO_PATTERN);CHKERRQ(ierr);
988     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
989     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
990   }
991   PetscFunctionReturn(0);
992 }
993 
994 /* ------------------------------------------------------------------------- */
995 /*
996  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
997    that was created with PCCreate_GAMG().
998 
999    Input Parameter:
1000 .  pc - the preconditioner context
1001 
1002    Application Interface Routine: PCDestroy()
1003 */
1004 #undef __FUNCT__
1005 #define __FUNCT__ "PCDestroy_GAMG"
1006 PetscErrorCode PCDestroy_GAMG(PC pc)
1007 {
1008   PetscErrorCode ierr;
1009   PC_MG          *mg     = (PC_MG*)pc->data;
1010   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
1011 
1012   PetscFunctionBegin;
1013   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
1014   if (pc_gamg->ops->destroy) {
1015     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1016   }
1017   ierr = PetscFree(pc_gamg->ops);CHKERRQ(ierr);
1018   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1019   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
1020   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
1021   PetscFunctionReturn(0);
1022 }
1023 
1024 
1025 #undef __FUNCT__
1026 #define __FUNCT__ "PCGAMGSetProcEqLim"
1027 /*@
1028    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via
1029    processor reduction.
1030 
1031    Not Collective on PC
1032 
1033    Input Parameters:
1034 .  pc - the preconditioner context
1035 
1036 
1037    Options Database Key:
1038 .  -pc_gamg_process_eq_limit
1039 
1040    Level: intermediate
1041 
1042    Concepts: Unstructured multrigrid preconditioner
1043 
1044 .seealso: ()
1045 @*/
1046 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
1047 {
1048   PetscErrorCode ierr;
1049 
1050   PetscFunctionBegin;
1051   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1052   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1053   PetscFunctionReturn(0);
1054 }
1055 
1056 #undef __FUNCT__
1057 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
1058 static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
1059 {
1060   PC_MG   *mg      = (PC_MG*)pc->data;
1061   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1062 
1063   PetscFunctionBegin;
1064   if (n>0) pc_gamg->min_eq_proc = n;
1065   PetscFunctionReturn(0);
1066 }
1067 
1068 #undef __FUNCT__
1069 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
1070 /*@
1071    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
1072 
1073  Collective on PC
1074 
1075    Input Parameters:
1076 .  pc - the preconditioner context
1077 
1078 
1079    Options Database Key:
1080 .  -pc_gamg_coarse_eq_limit
1081 
1082    Level: intermediate
1083 
1084    Concepts: Unstructured multrigrid preconditioner
1085 
1086 .seealso: ()
1087  @*/
1088 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
1089 {
1090   PetscErrorCode ierr;
1091 
1092   PetscFunctionBegin;
1093   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1094   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1095   PetscFunctionReturn(0);
1096 }
1097 
1098 #undef __FUNCT__
1099 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
1100 static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
1101 {
1102   PC_MG   *mg      = (PC_MG*)pc->data;
1103   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1104 
1105   PetscFunctionBegin;
1106   if (n>0) pc_gamg->coarse_eq_limit = n;
1107   PetscFunctionReturn(0);
1108 }
1109 
1110 #undef __FUNCT__
1111 #define __FUNCT__ "PCGAMGSetRepartitioning"
1112 /*@
1113    PCGAMGSetRepartitioning - Repartition the coarse grids
1114 
1115    Collective on PC
1116 
1117    Input Parameters:
1118 .  pc - the preconditioner context
1119 
1120 
1121    Options Database Key:
1122 .  -pc_gamg_repartition
1123 
1124    Level: intermediate
1125 
1126    Concepts: Unstructured multrigrid preconditioner
1127 
1128 .seealso: ()
1129 @*/
1130 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
1131 {
1132   PetscErrorCode ierr;
1133 
1134   PetscFunctionBegin;
1135   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1136   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1137   PetscFunctionReturn(0);
1138 }
1139 
1140 #undef __FUNCT__
1141 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
1142 static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
1143 {
1144   PC_MG   *mg      = (PC_MG*)pc->data;
1145   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1146 
1147   PetscFunctionBegin;
1148   pc_gamg->repart = n;
1149   PetscFunctionReturn(0);
1150 }
1151 
1152 #undef __FUNCT__
1153 #define __FUNCT__ "PCGAMGSetReuseProl"
1154 /*@
1155    PCGAMGSetReuseProl - Reuse prlongation
1156 
1157    Collective on PC
1158 
1159    Input Parameters:
1160 .  pc - the preconditioner context
1161 
1162 
1163    Options Database Key:
1164 .  -pc_gamg_reuse_interpolation
1165 
1166    Level: intermediate
1167 
1168    Concepts: Unstructured multrigrid preconditioner
1169 
1170 .seealso: ()
1171 @*/
1172 PetscErrorCode PCGAMGSetReuseProl(PC pc, PetscBool n)
1173 {
1174   PetscErrorCode ierr;
1175 
1176   PetscFunctionBegin;
1177   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1178   ierr = PetscTryMethod(pc,"PCGAMGSetReuseProl_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1179   PetscFunctionReturn(0);
1180 }
1181 
1182 #undef __FUNCT__
1183 #define __FUNCT__ "PCGAMGSetReuseProl_GAMG"
1184 static 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 
1194 #undef __FUNCT__
1195 #define __FUNCT__ "PCGAMGSetUseASMAggs"
1196 /*@
1197    PCGAMGSetUseASMAggs -
1198 
1199    Collective on PC
1200 
1201    Input Parameters:
1202 .  pc - the preconditioner context
1203 
1204 
1205    Options Database Key:
1206 .  -pc_gamg_use_agg_gasm
1207 
1208    Level: intermediate
1209 
1210    Concepts: Unstructured multrigrid preconditioner
1211 
1212 .seealso: ()
1213 @*/
1214 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1215 {
1216   PetscErrorCode ierr;
1217 
1218   PetscFunctionBegin;
1219   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1220   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1221   PetscFunctionReturn(0);
1222 }
1223 
1224 #undef __FUNCT__
1225 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
1226 static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
1227 {
1228   PC_MG   *mg      = (PC_MG*)pc->data;
1229   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1230 
1231   PetscFunctionBegin;
1232   pc_gamg->use_aggs_in_gasm = n;
1233   PetscFunctionReturn(0);
1234 }
1235 
1236 #undef __FUNCT__
1237 #define __FUNCT__ "PCGAMGSetNlevels"
1238 /*@
1239    PCGAMGSetNlevels -
1240 
1241    Not collective on PC
1242 
1243    Input Parameters:
1244 .  pc - the preconditioner context
1245 
1246 
1247    Options Database Key:
1248 .  -pc_mg_levels
1249 
1250    Level: intermediate
1251 
1252    Concepts: Unstructured multrigrid preconditioner
1253 
1254 .seealso: ()
1255 @*/
1256 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1257 {
1258   PetscErrorCode ierr;
1259 
1260   PetscFunctionBegin;
1261   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1262   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1263   PetscFunctionReturn(0);
1264 }
1265 
1266 #undef __FUNCT__
1267 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
1268 static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
1269 {
1270   PC_MG   *mg      = (PC_MG*)pc->data;
1271   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1272 
1273   PetscFunctionBegin;
1274   pc_gamg->Nlevels = n;
1275   PetscFunctionReturn(0);
1276 }
1277 
1278 #undef __FUNCT__
1279 #define __FUNCT__ "PCGAMGSetThreshold"
1280 /*@
1281    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph
1282 
1283    Not collective on PC
1284 
1285    Input Parameters:
1286 .  pc - the preconditioner context
1287 
1288 
1289    Options Database Key:
1290 .  -pc_gamg_threshold
1291 
1292    Level: intermediate
1293 
1294    Concepts: Unstructured multrigrid preconditioner
1295 
1296 .seealso: ()
1297 @*/
1298 PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
1299 {
1300   PetscErrorCode ierr;
1301 
1302   PetscFunctionBegin;
1303   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1304   ierr = PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));CHKERRQ(ierr);
1305   PetscFunctionReturn(0);
1306 }
1307 
1308 #undef __FUNCT__
1309 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
1310 static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
1311 {
1312   PC_MG   *mg      = (PC_MG*)pc->data;
1313   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1314 
1315   PetscFunctionBegin;
1316   pc_gamg->threshold = n;
1317   PetscFunctionReturn(0);
1318 }
1319 
1320 #undef __FUNCT__
1321 #define __FUNCT__ "PCGAMGSetType"
1322 /*@
1323    PCGAMGSetType - Set solution method - calls sub create method
1324 
1325    Collective on PC
1326 
1327    Input Parameters:
1328 .  pc - the preconditioner context
1329 
1330 
1331    Options Database Key:
1332 .  -pc_gamg_type
1333 
1334    Level: intermediate
1335 
1336    Concepts: Unstructured multrigrid preconditioner
1337 
1338 .seealso: ()
1339 @*/
1340 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1341 {
1342   PetscErrorCode ierr;
1343 
1344   PetscFunctionBegin;
1345   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1346   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1347   PetscFunctionReturn(0);
1348 }
1349 
1350 #undef __FUNCT__
1351 #define __FUNCT__ "PCGAMGSetType_GAMG"
1352 static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
1353 {
1354   PetscErrorCode ierr,(*r)(PC);
1355   PC_MG          *mg      = (PC_MG*)pc->data;
1356   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1357 
1358   PetscFunctionBegin;
1359   ierr = PetscFunctionListFind(GAMGList,type,&r);CHKERRQ(ierr);
1360   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
1361   if (pc_gamg->ops->destroy) {
1362     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1363     ierr = PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));CHKERRQ(ierr);
1364   }
1365   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1366   ierr = PetscStrallocpy(type,&pc_gamg->gamg_type_name);CHKERRQ(ierr);
1367   ierr = (*r)(pc);CHKERRQ(ierr);
1368   PetscFunctionReturn(0);
1369 }
1370 
1371 #undef __FUNCT__
1372 #define __FUNCT__ "PCSetFromOptions_GAMG"
1373 PetscErrorCode PCSetFromOptions_GAMG(PC pc)
1374 {
1375   PetscErrorCode ierr;
1376   PC_MG          *mg      = (PC_MG*)pc->data;
1377   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1378   PetscBool      flag;
1379   PetscInt       two   = 2;
1380   MPI_Comm       comm;
1381 
1382   PetscFunctionBegin;
1383   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1384   ierr = PetscOptionsHead("GAMG options");CHKERRQ(ierr);
1385   {
1386     /* -pc_gamg_type */
1387     {
1388       char tname[256] = PCGAMGAGG;
1389       const char *deftype = pc_gamg->gamg_type_name ? pc_gamg->gamg_type_name : tname;
1390       ierr = PetscOptionsList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, tname, tname, sizeof(tname), &flag);CHKERRQ(ierr);
1391       /* call PCCreateGAMG_XYZ */
1392       if (flag || !pc_gamg->gamg_type_name) {
1393         ierr = PCGAMGSetType(pc, flag ? tname : deftype);CHKERRQ(ierr);
1394       }
1395     }
1396     /* -pc_gamg_verbose */
1397     ierr = PetscOptionsInt("-pc_gamg_verbose","Verbose (debugging) output for PCGAMG",
1398                            "none", pc_gamg->verbose,
1399                            &pc_gamg->verbose, NULL);CHKERRQ(ierr);
1400     /* -pc_gamg_repartition */
1401     ierr = PetscOptionsBool("-pc_gamg_repartition",
1402                             "Repartion coarse grids (false)",
1403                             "PCGAMGRepartitioning",
1404                             pc_gamg->repart,
1405                             &pc_gamg->repart,
1406                             &flag);CHKERRQ(ierr);
1407     /* -pc_gamg_reuse_interpolation */
1408     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation",
1409                             "Reuse prolongation operator (true)",
1410                             "PCGAMGReuseProl",
1411                             pc_gamg->reuse_prol,
1412                             &pc_gamg->reuse_prol,
1413                             &flag);CHKERRQ(ierr);
1414     /* -pc_gamg_use_agg_gasm */
1415     ierr = PetscOptionsBool("-pc_gamg_use_agg_gasm",
1416                             "Use aggregation agragates for GASM smoother (false)",
1417                             "PCGAMGUseASMAggs",
1418                             pc_gamg->use_aggs_in_gasm,
1419                             &pc_gamg->use_aggs_in_gasm,
1420                             &flag);CHKERRQ(ierr);
1421     /* -pc_gamg_process_eq_limit */
1422     ierr = PetscOptionsInt("-pc_gamg_process_eq_limit",
1423                            "Limit (goal) on number of equations per process on coarse grids",
1424                            "PCGAMGSetProcEqLim",
1425                            pc_gamg->min_eq_proc,
1426                            &pc_gamg->min_eq_proc,
1427                            &flag);CHKERRQ(ierr);
1428     /* -pc_gamg_coarse_eq_limit */
1429     ierr = PetscOptionsInt("-pc_gamg_coarse_eq_limit",
1430                            "Limit on number of equations for the coarse grid",
1431                            "PCGAMGSetCoarseEqLim",
1432                            pc_gamg->coarse_eq_limit,
1433                            &pc_gamg->coarse_eq_limit,
1434                            &flag);CHKERRQ(ierr);
1435     /* -pc_gamg_threshold */
1436     ierr = PetscOptionsReal("-pc_gamg_threshold",
1437                             "Relative threshold to use for dropping edges in aggregation graph",
1438                             "PCGAMGSetThreshold",
1439                             pc_gamg->threshold,
1440                             &pc_gamg->threshold,
1441                             &flag);CHKERRQ(ierr);
1442     if (flag && pc_gamg->verbose) {
1443       ierr = PetscPrintf(comm,"\t[%d]%s threshold set %e\n",0,__FUNCT__,pc_gamg->threshold);CHKERRQ(ierr);
1444     }
1445     /* -pc_gamg_eigtarget */
1446     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1447     ierr = PetscOptionsInt("-pc_mg_levels",
1448                            "Set number of MG levels",
1449                            "PCGAMGSetNlevels",
1450                            pc_gamg->Nlevels,
1451                            &pc_gamg->Nlevels,
1452                            &flag);CHKERRQ(ierr);
1453 
1454     /* set options for subtype */
1455     if (pc_gamg->ops->setfromoptions) {ierr = (*pc_gamg->ops->setfromoptions)(pc);CHKERRQ(ierr);}
1456   }
1457   ierr = PetscOptionsTail();CHKERRQ(ierr);
1458   PetscFunctionReturn(0);
1459 }
1460 
1461 /* -------------------------------------------------------------------------- */
1462 /*MC
1463      PCGAMG - Geometric algebraic multigrid (AMG) preconditioning framework.
1464        - This is the entry point to GAMG, registered in pcregis.c
1465 
1466    Options Database Keys:
1467    Multigrid options(inherited)
1468 +  -pc_mg_cycles <1>: 1 for V cycle, 2 for W-cycle (PCMGSetCycleType)
1469 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
1470 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
1471 -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade
1472 
1473   Level: intermediate
1474 
1475   Concepts: multigrid
1476 
1477 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC, PCMGType,
1478            PCMGSetLevels(), PCMGGetLevels(), PCMGSetType(), PCMGSetCycleType(), PCMGSetNumberSmoothDown(),
1479            PCMGSetNumberSmoothUp(), PCMGGetCoarseSolve(), PCMGSetResidual(), PCMGSetInterpolation(),
1480            PCMGSetRestriction(), PCMGGetSmoother(), PCMGGetSmootherUp(), PCMGGetSmootherDown(),
1481            PCMGSetCyclesOnLevel(), PCMGSetRhs(), PCMGSetX(), PCMGSetR()
1482 M*/
1483 
1484 #undef __FUNCT__
1485 #define __FUNCT__ "PCCreate_GAMG"
1486 PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
1487 {
1488   PetscErrorCode ierr;
1489   PC_GAMG        *pc_gamg;
1490   PC_MG          *mg;
1491 #if defined PETSC_GAMG_USE_LOG
1492   static long count = 0;
1493 #endif
1494 
1495   PetscFunctionBegin;
1496   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1497   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr); /* calls PCCreate_MG() and MGCreate_Private() */
1498   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1499 
1500   /* create a supporting struct and attach it to pc */
1501   ierr         = PetscNewLog(pc, PC_GAMG, &pc_gamg);CHKERRQ(ierr);
1502   mg           = (PC_MG*)pc->data;
1503   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally */
1504   mg->innerctx = pc_gamg;
1505 
1506   ierr = PetscNewLog(pc,struct _PCGAMGOps,&pc_gamg->ops);CHKERRQ(ierr);
1507 
1508   pc_gamg->setup_count = 0;
1509   /* these should be in subctx but repartitioning needs simple arrays */
1510   pc_gamg->data_sz = 0;
1511   pc_gamg->data    = 0;
1512 
1513   /* register AMG type */
1514 #if !defined(PETSC_USE_DYNAMIC_LIBRARIES)
1515   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1516 #endif
1517 
1518   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
1519   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
1520   pc->ops->setup          = PCSetUp_GAMG;
1521   pc->ops->reset          = PCReset_GAMG;
1522   pc->ops->destroy        = PCDestroy_GAMG;
1523 
1524   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1525   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1526   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1527   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseProl_C",PCGAMGSetReuseProl_GAMG);CHKERRQ(ierr);
1528   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1529   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1530   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);CHKERRQ(ierr);
1531   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);CHKERRQ(ierr);
1532   pc_gamg->repart           = PETSC_FALSE;
1533   pc_gamg->reuse_prol       = PETSC_FALSE;
1534   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
1535   pc_gamg->min_eq_proc      = 50;
1536   pc_gamg->coarse_eq_limit  = 800;
1537   pc_gamg->threshold        = 0.;
1538   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
1539   pc_gamg->verbose          = 0;
1540   pc_gamg->emax_id          = -1;
1541   pc_gamg->eigtarget[0]     = 0.05;
1542   pc_gamg->eigtarget[1]     = 1.05;
1543 
1544   /* private events */
1545 #if defined PETSC_GAMG_USE_LOG
1546   if (count++ == 0) {
1547     ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1548     ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
1549     /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
1550     /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
1551     /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
1552     ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1553     ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1554     ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1555     ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1556     ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1557     ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1558     ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1559     ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1560     ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1561     ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1562     ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1563     ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1564 
1565     /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
1566     /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
1567     /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
1568     /* create timer stages */
1569 #if defined GAMG_STAGES
1570     {
1571       char     str[32];
1572       PetscInt lidx;
1573       sprintf(str,"MG Level %d (finest)",0);
1574       ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1575       for (lidx=1; lidx<9; lidx++) {
1576         sprintf(str,"MG Level %d",lidx);
1577         ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1578       }
1579     }
1580 #endif
1581   }
1582 #endif
1583   /* general events */
1584 #if defined PETSC_USE_LOG
1585   ierr = PetscLogEventRegister("PCGAMGgraph_AGG", 0, &PC_GAMGGgraph_AGG);CHKERRQ(ierr);
1586   ierr = PetscLogEventRegister("PCGAMGgraph_GEO", PC_CLASSID, &PC_GAMGGgraph_GEO);CHKERRQ(ierr);
1587   ierr = PetscLogEventRegister("PCGAMGcoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1588   ierr = PetscLogEventRegister("PCGAMGcoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1589   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1590   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1591   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptprol_AGG);CHKERRQ(ierr);
1592   ierr = PetscLogEventRegister("GAMGKKTProl_AGG", PC_CLASSID, &PC_GAMGKKTProl_AGG);CHKERRQ(ierr);
1593 #endif
1594 
1595   PetscFunctionReturn(0);
1596 }
1597 
1598 #undef __FUNCT__
1599 #define __FUNCT__ "PCGAMGInitializePackage"
1600 /*@C
1601  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
1602  from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
1603  when using static libraries.
1604 
1605  Level: developer
1606 
1607  .keywords: PC, PCGAMG, initialize, package
1608  .seealso: PetscInitialize()
1609 @*/
1610 PetscErrorCode PCGAMGInitializePackage(void)
1611 {
1612   PetscErrorCode ierr;
1613 
1614   PetscFunctionBegin;
1615   if (PCGAMGPackageInitialized) PetscFunctionReturn(0);
1616   PCGAMGPackageInitialized = PETSC_TRUE;
1617   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);CHKERRQ(ierr);
1618   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);CHKERRQ(ierr);
1619   ierr = PetscRegisterFinalize(PCGAMGFinalizePackage);CHKERRQ(ierr);
1620   PetscFunctionReturn(0);
1621 }
1622 
1623 #undef __FUNCT__
1624 #define __FUNCT__ "PCGAMGFinalizePackage"
1625 /*@C
1626  PCGAMGFinalizePackage - This function destroys everything in the PCGAMG package. It is
1627  called from PetscFinalize().
1628 
1629  Level: developer
1630 
1631  .keywords: Petsc, destroy, package
1632  .seealso: PetscFinalize()
1633 @*/
1634 PetscErrorCode PCGAMGFinalizePackage(void)
1635 {
1636   PetscErrorCode ierr;
1637 
1638   PetscFunctionBegin;
1639   PCGAMGPackageInitialized = PETSC_FALSE;
1640   ierr = PetscFunctionListDestroy(&GAMGList);CHKERRQ(ierr);
1641   PetscFunctionReturn(0);
1642 }
1643