xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision d9558ea91a0ca1fa4633d87e21172ffbe9a39015)
1 /*
2  GAMG geometric-algebric multigrid PC - Mark Adams 2011
3  */
4 #include <petsc-private/matimpl.h>
5 #include <../src/ksp/pc/impls/gamg/gamg.h>           /*I "petscpc.h" I*/
6 #include <petsc-private/kspimpl.h>
7 #include <../src/ksp/pc/impls/bjacobi/bjacobi.h> /* Hack to access same_local_solves */
8 
9 #if defined PETSC_GAMG_USE_LOG
10 PetscLogEvent petsc_gamg_setup_events[NUM_SET];
11 #endif
12 
13 #if defined PETSC_USE_LOG
14 PetscLogEvent PC_GAMGGraph_AGG;
15 PetscLogEvent PC_GAMGGraph_GEO;
16 PetscLogEvent PC_GAMGCoarsen_AGG;
17 PetscLogEvent PC_GAMGCoarsen_GEO;
18 PetscLogEvent PC_GAMGProlongator_AGG;
19 PetscLogEvent PC_GAMGProlongator_GEO;
20 PetscLogEvent PC_GAMGOptProlongator_AGG;
21 #endif
22 
23 #define GAMG_MAXLEVELS 30
24 
25 /* #define GAMG_STAGES */
26 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
27 static PetscLogStage gamg_stages[GAMG_MAXLEVELS];
28 #endif
29 
30 static PetscFunctionList GAMGList = 0;
31 static PetscBool PCGAMGPackageInitialized;
32 
33 /* ----------------------------------------------------------------------------- */
34 #undef __FUNCT__
35 #define __FUNCT__ "PCReset_GAMG"
36 PetscErrorCode PCReset_GAMG(PC pc)
37 {
38   PetscErrorCode ierr;
39   PC_MG          *mg      = (PC_MG*)pc->data;
40   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
41 
42   PetscFunctionBegin;
43   if (pc_gamg->data) { /* this should not happen, cleaned up in SetUp */
44     PetscPrintf(PetscObjectComm((PetscObject)pc),"***[%d]%s this should not happen, cleaned up in SetUp\n",0,__FUNCT__);
45     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
46   }
47   pc_gamg->data_sz = 0;
48   ierr = PetscFree(pc_gamg->orig_data);CHKERRQ(ierr);
49   PetscFunctionReturn(0);
50 }
51 
52 /* -------------------------------------------------------------------------- */
53 /*
54    PCGAMGCreateLevel_GAMG: create coarse op with RAP.  repartition and/or reduce number
55      of active processors.
56 
57    Input Parameter:
58    . pc - parameters + side effect: coarse data in 'pc_gamg->data' and
59           'pc_gamg->data_sz' are changed via repartitioning/reduction.
60    . Amat_fine - matrix on this fine (k) level
61    . cr_bs - coarse block size
62    In/Output Parameter:
63    . a_P_inout - prolongation operator to the next level (k-->k-1)
64    . a_nactive_proc - number of active procs
65    Output Parameter:
66    . a_Amat_crs - coarse matrix that is created (k-1)
67 */
68 
69 #undef __FUNCT__
70 #define __FUNCT__ "PCGAMGCreateLevel_GAMG"
71 static PetscErrorCode PCGAMGCreateLevel_GAMG(PC pc,Mat Amat_fine,PetscInt cr_bs,
72                                   Mat *a_P_inout,Mat *a_Amat_crs,PetscMPIInt *a_nactive_proc,
73                                   IS * Pcolumnperm)
74 {
75   PetscErrorCode  ierr;
76   PC_MG           *mg         = (PC_MG*)pc->data;
77   PC_GAMG         *pc_gamg    = (PC_GAMG*)mg->innerctx;
78   Mat             Cmat,Pold=*a_P_inout;
79   MPI_Comm        comm;
80   PetscMPIInt     rank,size,new_size,nactive=*a_nactive_proc;
81   PetscInt        ncrs_eq,ncrs,f_bs;
82 
83   PetscFunctionBegin;
84   ierr = PetscObjectGetComm((PetscObject)Amat_fine,&comm);CHKERRQ(ierr);
85   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
86   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
87   ierr = MatGetBlockSize(Amat_fine, &f_bs);CHKERRQ(ierr);
88   ierr = MatPtAP(Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat);CHKERRQ(ierr);
89 
90   /* set 'ncrs' (nodes), 'ncrs_eq' (equations)*/
91   ierr = MatGetLocalSize(Cmat, &ncrs_eq, NULL);CHKERRQ(ierr);
92   if (pc_gamg->data_cell_rows>0) {
93     ncrs = pc_gamg->data_sz/pc_gamg->data_cell_cols/pc_gamg->data_cell_rows;
94   } else {
95     PetscInt  bs;
96     ierr = MatGetBlockSize(Cmat, &bs);CHKERRQ(ierr);
97     ncrs = ncrs_eq/bs;
98   }
99 
100   /* get number of PEs to make active 'new_size', reduce, can be any integer 1-P */
101   {
102     PetscInt ncrs_eq_glob;
103     ierr     = MatGetSize(Cmat, &ncrs_eq_glob, NULL);CHKERRQ(ierr);
104     new_size = (PetscMPIInt)((float)ncrs_eq_glob/(float)pc_gamg->min_eq_proc + 0.5); /* hardwire min. number of eq/proc */
105     if (new_size == 0) new_size = 1; /* not likely, posible? */
106     else if (new_size >= nactive) new_size = nactive; /* no change, rare */
107   }
108 
109   if (Pcolumnperm) *Pcolumnperm = NULL;
110 
111   if (!pc_gamg->repart && new_size==nactive) *a_Amat_crs = Cmat; /* output - no repartitioning or reduction - could bail here */
112   else {
113     PetscInt       *counts,*newproc_idx,ii,jj,kk,strideNew,*tidx,ncrs_new,ncrs_eq_new,nloc_old;
114     IS             is_eq_newproc,is_eq_num,is_eq_num_prim,new_eq_indices;
115 
116     nloc_old = ncrs_eq/cr_bs;
117     if (ncrs_eq % cr_bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ncrs_eq %D not divisible by cr_bs %D",ncrs_eq,cr_bs);
118 #if defined PETSC_GAMG_USE_LOG
119     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
120 #endif
121     /* make 'is_eq_newproc' */
122     ierr = PetscMalloc1(size, &counts);CHKERRQ(ierr);
123     if (pc_gamg->repart) {
124       /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates of primal part accordingly */
125       Mat adj;
126 
127      ierr = PetscInfo3(pc,"\t repartition: size (active): %D --> %D, neq = %D\n",*a_nactive_proc,new_size,ncrs_eq);
128 
129       /* get 'adj' */
130       if (cr_bs == 1) {
131         ierr = MatConvert(Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
132       } else {
133         /* make a scalar matrix to partition (no Stokes here) */
134         Mat               tMat;
135         PetscInt          Istart_crs,Iend_crs,ncols,jj,Ii;
136         const PetscScalar *vals;
137         const PetscInt    *idx;
138         PetscInt          *d_nnz, *o_nnz, M, N;
139         static PetscInt   llev = 0;
140         MatType           mtype;
141 
142         ierr = PetscMalloc1(ncrs, &d_nnz);CHKERRQ(ierr);
143         ierr = PetscMalloc1(ncrs, &o_nnz);CHKERRQ(ierr);
144         ierr = MatGetOwnershipRange(Cmat, &Istart_crs, &Iend_crs);CHKERRQ(ierr);
145         ierr = MatGetSize(Cmat, &M, &N);CHKERRQ(ierr);
146         for (Ii = Istart_crs, jj = 0; Ii < Iend_crs; Ii += cr_bs, jj++) {
147           ierr      = MatGetRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
148           d_nnz[jj] = ncols/cr_bs;
149           o_nnz[jj] = ncols/cr_bs;
150           ierr      = MatRestoreRow(Cmat,Ii,&ncols,0,0);CHKERRQ(ierr);
151           if (d_nnz[jj] > ncrs) d_nnz[jj] = ncrs;
152           if (o_nnz[jj] > (M/cr_bs-ncrs)) o_nnz[jj] = M/cr_bs-ncrs;
153         }
154 
155         ierr = MatGetType(Amat_fine,&mtype);CHKERRQ(ierr);
156         ierr = MatCreate(comm, &tMat);CHKERRQ(ierr);
157         ierr = MatSetSizes(tMat, ncrs, ncrs,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
158         ierr = MatSetType(tMat,mtype);CHKERRQ(ierr);
159         ierr = MatSeqAIJSetPreallocation(tMat,0,d_nnz);CHKERRQ(ierr);
160         ierr = MatMPIAIJSetPreallocation(tMat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
161         ierr = PetscFree(d_nnz);CHKERRQ(ierr);
162         ierr = PetscFree(o_nnz);CHKERRQ(ierr);
163 
164         for (ii = Istart_crs; ii < Iend_crs; ii++) {
165           PetscInt dest_row = ii/cr_bs;
166           ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
167           for (jj = 0; jj < ncols; jj++) {
168             PetscInt    dest_col = idx[jj]/cr_bs;
169             PetscScalar v        = 1.0;
170             ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES);CHKERRQ(ierr);
171           }
172           ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals);CHKERRQ(ierr);
173         }
174         ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
175         ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
176 
177         if (llev++ == -1) {
178           PetscViewer viewer; char fname[32];
179           ierr = PetscSNPrintf(fname,sizeof(fname),"part_mat_%D.mat",llev);CHKERRQ(ierr);
180           PetscViewerBinaryOpen(comm,fname,FILE_MODE_WRITE,&viewer);
181           ierr = MatView(tMat, viewer);CHKERRQ(ierr);
182           ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
183         }
184 
185         ierr = MatConvert(tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj);CHKERRQ(ierr);
186 
187         ierr = MatDestroy(&tMat);CHKERRQ(ierr);
188       } /* create 'adj' */
189 
190       { /* partition: get newproc_idx */
191         char            prefix[256];
192         const char      *pcpre;
193         const PetscInt  *is_idx;
194         MatPartitioning mpart;
195         IS              proc_is;
196         PetscInt        targetPE;
197 
198         ierr = MatPartitioningCreate(comm, &mpart);CHKERRQ(ierr);
199         ierr = MatPartitioningSetAdjacency(mpart, adj);CHKERRQ(ierr);
200         ierr = PCGetOptionsPrefix(pc, &pcpre);CHKERRQ(ierr);
201         ierr = PetscSNPrintf(prefix,sizeof(prefix),"%spc_gamg_",pcpre ? pcpre : "");CHKERRQ(ierr);
202         ierr = PetscObjectSetOptionsPrefix((PetscObject)mpart,prefix);CHKERRQ(ierr);
203         ierr = MatPartitioningSetFromOptions(mpart);CHKERRQ(ierr);
204         ierr = MatPartitioningSetNParts(mpart, new_size);CHKERRQ(ierr);
205         ierr = MatPartitioningApply(mpart, &proc_is);CHKERRQ(ierr);
206         ierr = MatPartitioningDestroy(&mpart);CHKERRQ(ierr);
207 
208         /* collect IS info */
209         ierr     = PetscMalloc1(ncrs_eq, &newproc_idx);CHKERRQ(ierr);
210         ierr     = ISGetIndices(proc_is, &is_idx);CHKERRQ(ierr);
211         targetPE = 1; /* bring to "front" of machine */
212         /*targetPE = size/new_size;*/ /* spread partitioning across machine */
213         for (kk = jj = 0 ; kk < nloc_old ; kk++) {
214           for (ii = 0 ; ii < cr_bs ; ii++, jj++) {
215             newproc_idx[jj] = is_idx[kk] * targetPE; /* distribution */
216           }
217         }
218         ierr = ISRestoreIndices(proc_is, &is_idx);CHKERRQ(ierr);
219         ierr = ISDestroy(&proc_is);CHKERRQ(ierr);
220       }
221       ierr = MatDestroy(&adj);CHKERRQ(ierr);
222 
223       ierr = ISCreateGeneral(comm, ncrs_eq, newproc_idx, PETSC_COPY_VALUES, &is_eq_newproc);CHKERRQ(ierr);
224       ierr = PetscFree(newproc_idx);CHKERRQ(ierr);
225     } else { /* simple aggreagtion of parts -- 'is_eq_newproc' */
226 
227       PetscInt rfactor,targetPE;
228       /* find factor */
229       if (new_size == 1) rfactor = size; /* easy */
230       else {
231         PetscReal best_fact = 0.;
232         jj = -1;
233         for (kk = 1 ; kk <= size ; kk++) {
234           if (size%kk==0) { /* a candidate */
235             PetscReal nactpe = (PetscReal)size/(PetscReal)kk, fact = nactpe/(PetscReal)new_size;
236             if (fact > 1.0) fact = 1./fact; /* keep fact < 1 */
237             if (fact > best_fact) {
238               best_fact = fact; jj = kk;
239             }
240           }
241         }
242         if (jj != -1) rfactor = jj;
243         else rfactor = 1; /* does this happen .. a prime */
244       }
245       new_size = size/rfactor;
246 
247       if (new_size==nactive) {
248         *a_Amat_crs = Cmat; /* output - no repartitioning or reduction, bail out because nested here */
249         ierr        = PetscFree(counts);CHKERRQ(ierr);
250         ierr = PetscInfo2(pc,"\t aggregate processors noop: new_size=%D, neq(loc)=%D\n",new_size,ncrs_eq);
251         PetscFunctionReturn(0);
252       }
253 
254       ierr = PetscInfo1(pc,"\t number of equations (loc) %D with simple aggregation\n",ncrs_eq);
255       targetPE = rank/rfactor;
256       ierr     = ISCreateStride(comm, ncrs_eq, targetPE, 0, &is_eq_newproc);CHKERRQ(ierr);
257     } /* end simple 'is_eq_newproc' */
258 
259     /*
260      Create an index set from the is_eq_newproc index set to indicate the mapping TO
261      */
262     ierr = ISPartitioningToNumbering(is_eq_newproc, &is_eq_num);CHKERRQ(ierr);
263     is_eq_num_prim = is_eq_num;
264     /*
265       Determine how many equations/vertices are assigned to each processor
266      */
267     ierr        = ISPartitioningCount(is_eq_newproc, size, counts);CHKERRQ(ierr);
268     ncrs_eq_new = counts[rank];
269     ierr        = ISDestroy(&is_eq_newproc);CHKERRQ(ierr);
270     ncrs_new = ncrs_eq_new/cr_bs; /* eqs */
271 
272     ierr = PetscFree(counts);CHKERRQ(ierr);
273 #if defined PETSC_GAMG_USE_LOG
274     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
275 #endif
276     /* data movement scope -- this could be moved to subclasses so that we don't try to cram all auxilary data into some complex abstracted thing */
277     {
278     Vec            src_crd, dest_crd;
279     const PetscInt *idx,ndata_rows=pc_gamg->data_cell_rows,ndata_cols=pc_gamg->data_cell_cols,node_data_sz=ndata_rows*ndata_cols;
280     VecScatter     vecscat;
281     PetscScalar    *array;
282     IS isscat;
283 
284     /* move data (for primal equations only) */
285     /* Create a vector to contain the newly ordered element information */
286     ierr = VecCreate(comm, &dest_crd);CHKERRQ(ierr);
287     ierr = VecSetSizes(dest_crd, node_data_sz*ncrs_new, PETSC_DECIDE);CHKERRQ(ierr);
288     ierr = VecSetType(dest_crd,VECSTANDARD);CHKERRQ(ierr); /* this is needed! */
289     /*
290      There are 'ndata_rows*ndata_cols' data items per node, (one can think of the vectors of having
291      a block size of ...).  Note, ISs are expanded into equation space by 'cr_bs'.
292      */
293     ierr = PetscMalloc1(ncrs*node_data_sz, &tidx);CHKERRQ(ierr);
294     ierr = ISGetIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
295     for (ii=0,jj=0; ii<ncrs; ii++) {
296       PetscInt id = idx[ii*cr_bs]/cr_bs; /* get node back */
297       for (kk=0; kk<node_data_sz; kk++, jj++) tidx[jj] = id*node_data_sz + kk;
298     }
299     ierr = ISRestoreIndices(is_eq_num_prim, &idx);CHKERRQ(ierr);
300     ierr = ISCreateGeneral(comm, node_data_sz*ncrs, tidx, PETSC_COPY_VALUES, &isscat);CHKERRQ(ierr);
301     ierr = PetscFree(tidx);CHKERRQ(ierr);
302     /*
303      Create a vector to contain the original vertex information for each element
304      */
305     ierr = VecCreateSeq(PETSC_COMM_SELF, node_data_sz*ncrs, &src_crd);CHKERRQ(ierr);
306     for (jj=0; jj<ndata_cols; jj++) {
307       const PetscInt stride0=ncrs*pc_gamg->data_cell_rows;
308       for (ii=0; ii<ncrs; ii++) {
309         for (kk=0; kk<ndata_rows; kk++) {
310           PetscInt    ix = ii*ndata_rows + kk + jj*stride0, jx = ii*node_data_sz + kk*ndata_cols + jj;
311           PetscScalar tt = (PetscScalar)pc_gamg->data[ix];
312           ierr = VecSetValues(src_crd, 1, &jx, &tt, INSERT_VALUES);CHKERRQ(ierr);
313         }
314       }
315     }
316     ierr = VecAssemblyBegin(src_crd);CHKERRQ(ierr);
317     ierr = VecAssemblyEnd(src_crd);CHKERRQ(ierr);
318     /*
319       Scatter the element vertex information (still in the original vertex ordering)
320       to the correct processor
321     */
322     ierr = VecScatterCreate(src_crd, NULL, dest_crd, isscat, &vecscat);CHKERRQ(ierr);
323     ierr = ISDestroy(&isscat);CHKERRQ(ierr);
324     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
325     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
326     ierr = VecScatterDestroy(&vecscat);CHKERRQ(ierr);
327     ierr = VecDestroy(&src_crd);CHKERRQ(ierr);
328     /*
329       Put the element vertex data into a new allocation of the gdata->ele
330     */
331     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
332     ierr = PetscMalloc1(node_data_sz*ncrs_new, &pc_gamg->data);CHKERRQ(ierr);
333 
334     pc_gamg->data_sz = node_data_sz*ncrs_new;
335     strideNew        = ncrs_new*ndata_rows;
336 
337     ierr = VecGetArray(dest_crd, &array);CHKERRQ(ierr);
338     for (jj=0; jj<ndata_cols; jj++) {
339       for (ii=0; ii<ncrs_new; ii++) {
340         for (kk=0; kk<ndata_rows; kk++) {
341           PetscInt ix = ii*ndata_rows + kk + jj*strideNew, jx = ii*node_data_sz + kk*ndata_cols + jj;
342           pc_gamg->data[ix] = PetscRealPart(array[jx]);
343         }
344       }
345     }
346     ierr = VecRestoreArray(dest_crd, &array);CHKERRQ(ierr);
347     ierr = VecDestroy(&dest_crd);CHKERRQ(ierr);
348     }
349     /* move A and P (columns) with new layout */
350 #if defined PETSC_GAMG_USE_LOG
351     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
352 #endif
353 
354     /*
355       Invert for MatGetSubMatrix
356     */
357     ierr = ISInvertPermutation(is_eq_num, ncrs_eq_new, &new_eq_indices);CHKERRQ(ierr);
358     ierr = ISSort(new_eq_indices);CHKERRQ(ierr); /* is this needed? */
359     ierr = ISSetBlockSize(new_eq_indices, cr_bs);CHKERRQ(ierr);
360     if (is_eq_num != is_eq_num_prim) {
361       ierr = ISDestroy(&is_eq_num_prim);CHKERRQ(ierr); /* could be same as 'is_eq_num' */
362     }
363     if (Pcolumnperm) {
364       ierr = PetscObjectReference((PetscObject)new_eq_indices);CHKERRQ(ierr);
365       *Pcolumnperm = new_eq_indices;
366     }
367     ierr = ISDestroy(&is_eq_num);CHKERRQ(ierr);
368 #if defined PETSC_GAMG_USE_LOG
369     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET13],0,0,0,0);CHKERRQ(ierr);
370     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
371 #endif
372     /* 'a_Amat_crs' output */
373     {
374       Mat mat;
375       ierr        = MatGetSubMatrix(Cmat, new_eq_indices, new_eq_indices, MAT_INITIAL_MATRIX, &mat);CHKERRQ(ierr);
376       *a_Amat_crs = mat;
377 
378       if (!PETSC_TRUE) {
379         PetscInt cbs, rbs;
380         ierr = MatGetBlockSizes(Cmat, &rbs, &cbs);CHKERRQ(ierr);
381         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Old Mat rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
382         ierr = MatGetBlockSizes(mat, &rbs, &cbs);CHKERRQ(ierr);
383         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);
384       }
385     }
386     ierr = MatDestroy(&Cmat);CHKERRQ(ierr);
387 
388 #if defined PETSC_GAMG_USE_LOG
389     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET14],0,0,0,0);CHKERRQ(ierr);
390 #endif
391     /* prolongator */
392     {
393       IS       findices;
394       PetscInt Istart,Iend;
395       Mat      Pnew;
396       ierr = MatGetOwnershipRange(Pold, &Istart, &Iend);CHKERRQ(ierr);
397 #if defined PETSC_GAMG_USE_LOG
398       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
399 #endif
400       ierr = ISCreateStride(comm,Iend-Istart,Istart,1,&findices);CHKERRQ(ierr);
401       ierr = ISSetBlockSize(findices,f_bs);CHKERRQ(ierr);
402       ierr = MatGetSubMatrix(Pold, findices, new_eq_indices, MAT_INITIAL_MATRIX, &Pnew);CHKERRQ(ierr);
403       ierr = ISDestroy(&findices);CHKERRQ(ierr);
404 
405       if (!PETSC_TRUE) {
406         PetscInt cbs, rbs;
407         ierr = MatGetBlockSizes(Pold, &rbs, &cbs);CHKERRQ(ierr);
408         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pold rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
409         ierr = MatGetBlockSizes(Pnew, &rbs, &cbs);CHKERRQ(ierr);
410         ierr = PetscPrintf(MPI_COMM_SELF,"[%d]%s Pnew rbs=%d cbs=%d\n",rank,__FUNCT__,rbs,cbs);CHKERRQ(ierr);
411       }
412 #if defined PETSC_GAMG_USE_LOG
413       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET15],0,0,0,0);CHKERRQ(ierr);
414 #endif
415       ierr = MatDestroy(a_P_inout);CHKERRQ(ierr);
416 
417       /* output - repartitioned */
418       *a_P_inout = Pnew;
419     }
420     ierr = ISDestroy(&new_eq_indices);CHKERRQ(ierr);
421 
422     *a_nactive_proc = new_size; /* output */
423   }
424 
425   /* outout matrix data */
426   if (!PETSC_TRUE) {
427     PetscViewer viewer; char fname[32]; static int llev=0; Cmat = *a_Amat_crs;
428     if (llev==0) {
429       sprintf(fname,"Cmat_%d.m",llev++);
430       PetscViewerASCIIOpen(comm,fname,&viewer);
431       ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
432       ierr = MatView(Amat_fine, viewer);CHKERRQ(ierr);
433       ierr = PetscViewerDestroy(&viewer);
434     }
435     sprintf(fname,"Cmat_%d.m",llev++);
436     PetscViewerASCIIOpen(comm,fname,&viewer);
437     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
438     ierr = MatView(Cmat, viewer);CHKERRQ(ierr);
439     ierr = PetscViewerDestroy(&viewer);
440   }
441   PetscFunctionReturn(0);
442 }
443 
444 /* -------------------------------------------------------------------------- */
445 /*
446    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
447                     by setting data structures and options.
448 
449    Input Parameter:
450 .  pc - the preconditioner context
451 
452 */
453 #undef __FUNCT__
454 #define __FUNCT__ "PCSetUp_GAMG"
455 PetscErrorCode PCSetUp_GAMG(PC pc)
456 {
457   PetscErrorCode ierr;
458   PC_MG          *mg      = (PC_MG*)pc->data;
459   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
460   Mat            Pmat     = pc->pmat;
461   PetscInt       fine_level,level,level1,bs,M,qq,lidx,nASMBlocksArr[GAMG_MAXLEVELS];
462   MPI_Comm       comm;
463   PetscMPIInt    rank,size,nactivepe;
464   Mat            Aarr[GAMG_MAXLEVELS],Parr[GAMG_MAXLEVELS];
465   PetscReal      emaxs[GAMG_MAXLEVELS];
466   IS             *ASMLocalIDsArr[GAMG_MAXLEVELS];
467   PetscLogDouble nnz0=0.,nnztot=0.;
468 
469   PetscFunctionBegin;
470   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
471   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
472   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
473 
474   if (pc_gamg->setup_count++ > 0) {
475     if ((PetscBool)(!pc_gamg->reuse_prol)) {
476       /* reset everything */
477       ierr = PCReset_MG(pc);CHKERRQ(ierr);
478       pc->setupcalled = 0;
479     } else {
480       PC_MG_Levels **mglevels = mg->levels;
481       /* just do Galerkin grids */
482       Mat          B,dA,dB;
483 
484      if (!pc->setupcalled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"PCSetUp() has not been called yet");
485       if (pc_gamg->Nlevels > 1) {
486         /* currently only handle case where mat and pmat are the same on coarser levels */
487         ierr = KSPGetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,&dA,&dB);CHKERRQ(ierr);
488         /* (re)set to get dirty flag */
489         ierr = KSPSetOperators(mglevels[pc_gamg->Nlevels-1]->smoothd,dA,dB);CHKERRQ(ierr);
490 
491         for (level=pc_gamg->Nlevels-2; level>=0; level--) {
492           /* the first time through the matrix structure has changed from repartitioning */
493           if (pc_gamg->setup_count==2) {
494             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_INITIAL_MATRIX,1.0,&B);CHKERRQ(ierr);
495             ierr = MatDestroy(&mglevels[level]->A);CHKERRQ(ierr);
496 
497             mglevels[level]->A = B;
498           } else {
499             ierr = KSPGetOperators(mglevels[level]->smoothd,NULL,&B);CHKERRQ(ierr);
500             ierr = MatPtAP(dB,mglevels[level+1]->interpolate,MAT_REUSE_MATRIX,1.0,&B);CHKERRQ(ierr);
501           }
502           ierr = KSPSetOperators(mglevels[level]->smoothd,B,B);CHKERRQ(ierr);
503           dB   = B;
504         }
505       }
506 
507       ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
508 
509       PetscFunctionReturn(0);
510     }
511   }
512 
513   if (!pc_gamg->data) {
514     if (pc_gamg->orig_data) {
515       ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
516       ierr = MatGetLocalSize(Pmat, &qq, NULL);CHKERRQ(ierr);
517 
518       pc_gamg->data_sz        = (qq/bs)*pc_gamg->orig_data_cell_rows*pc_gamg->orig_data_cell_cols;
519       pc_gamg->data_cell_rows = pc_gamg->orig_data_cell_rows;
520       pc_gamg->data_cell_cols = pc_gamg->orig_data_cell_cols;
521 
522       ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->data);CHKERRQ(ierr);
523       for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->data[qq] = pc_gamg->orig_data[qq];
524     } else {
525       if (!pc_gamg->ops->createdefaultdata) SETERRQ(comm,PETSC_ERR_PLIB,"'createdefaultdata' not set(?) need to support NULL data");
526       ierr = pc_gamg->ops->createdefaultdata(pc,Pmat);CHKERRQ(ierr);
527     }
528   }
529 
530   /* cache original data for reuse */
531   if (!pc_gamg->orig_data && (PetscBool)(!pc_gamg->reuse_prol)) {
532     ierr = PetscMalloc1(pc_gamg->data_sz, &pc_gamg->orig_data);CHKERRQ(ierr);
533     for (qq=0; qq<pc_gamg->data_sz; qq++) pc_gamg->orig_data[qq] = pc_gamg->data[qq];
534     pc_gamg->orig_data_cell_rows = pc_gamg->data_cell_rows;
535     pc_gamg->orig_data_cell_cols = pc_gamg->data_cell_cols;
536   }
537 
538   /* get basic dims */
539   ierr = MatGetBlockSize(Pmat, &bs);CHKERRQ(ierr);
540   ierr = MatGetSize(Pmat, &M, &qq);CHKERRQ(ierr);
541 
542   /* Get A_i and R_i */
543   for (level=0, Aarr[0]=Pmat, nactivepe = size; /* hard wired stopping logic */
544        level < (pc_gamg->Nlevels-1) && (level==0 || M>pc_gamg->coarse_eq_limit);
545        level++) {
546     pc_gamg->firstCoarsen = (level ? PETSC_FALSE : PETSC_TRUE);
547     level1 = level + 1;
548 #if defined PETSC_GAMG_USE_LOG
549     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
550 #if (defined GAMG_STAGES)
551     ierr = PetscLogStagePush(gamg_stages[level]);CHKERRQ(ierr);
552 #endif
553 #endif
554     { /* construct prolongator */
555       Mat              Gmat;
556       PetscCoarsenData *agg_lists;
557       Mat              Prol11;
558 
559       ierr = pc_gamg->ops->graph(pc,Aarr[level], &Gmat);CHKERRQ(ierr);
560       ierr = pc_gamg->ops->coarsen(pc, &Gmat, &agg_lists);CHKERRQ(ierr);
561       ierr = pc_gamg->ops->prolongator(pc,Aarr[level],Gmat,agg_lists,&Prol11);CHKERRQ(ierr);
562 
563       /* could have failed to create new level */
564       if (Prol11) {
565         /* get new block size of coarse matrices */
566         ierr = MatGetBlockSizes(Prol11, NULL, &bs);CHKERRQ(ierr);
567 
568         if (pc_gamg->ops->optprolongator) {
569           /* smooth */
570           ierr = pc_gamg->ops->optprolongator(pc, Aarr[level], &Prol11);CHKERRQ(ierr);
571         }
572 
573         Parr[level1] = Prol11;
574       } else Parr[level1] = NULL;
575 
576       if (pc_gamg->use_aggs_in_gasm) {
577         PetscInt bs;
578         ierr = MatGetBlockSizes(Prol11, &bs, NULL);CHKERRQ(ierr);
579         ierr = PetscCDGetASMBlocks(agg_lists, bs, &nASMBlocksArr[level], &ASMLocalIDsArr[level]);CHKERRQ(ierr);
580       }
581 
582       ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
583       ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
584     } /* construct prolongator scope */
585 #if defined PETSC_GAMG_USE_LOG
586     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
587 #endif
588     /* cache eigen estimate */
589     if (pc_gamg->emax_id != -1) {
590       PetscBool flag;
591       ierr = PetscObjectComposedDataGetReal((PetscObject)Aarr[level], pc_gamg->emax_id, emaxs[level], flag);CHKERRQ(ierr);
592       if (!flag) emaxs[level] = -1.;
593     } else emaxs[level] = -1.;
594     if (level==0) Aarr[0] = Pmat; /* use Pmat for finest level setup */
595     if (!Parr[level1]) {
596       ierr =  PetscInfo1(pc,"\t stop gridding, level %D\n",level);CHKERRQ(ierr);
597 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
598       ierr = PetscLogStagePop();CHKERRQ(ierr);
599 #endif
600       break;
601     }
602 #if defined PETSC_GAMG_USE_LOG
603     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
604 #endif
605 
606     ierr = pc_gamg->ops->createlevel(pc, Aarr[level], bs,&Parr[level1], &Aarr[level1], &nactivepe, NULL);CHKERRQ(ierr);
607 
608 #if defined PETSC_GAMG_USE_LOG
609     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
610 #endif
611     ierr = MatGetSize(Aarr[level1], &M, &qq);CHKERRQ(ierr);
612 #if (defined PETSC_GAMG_USE_LOG && defined GAMG_STAGES)
613     ierr = PetscLogStagePop();CHKERRQ(ierr);
614 #endif
615     /* stop if one node or one proc -- could pull back for singular problems */
616     if ( (pc_gamg->data_cell_cols && M/pc_gamg->data_cell_cols < 2) || (!pc_gamg->data_cell_cols && M < 2) ) {
617       ierr =  PetscInfo1(pc,"\t HARD stop of coarsening ?????????, level %D\n",level);CHKERRQ(ierr);
618       level++;
619       break;
620     }
621   } /* levels */
622   pc_gamg->firstCoarsen = PETSC_FALSE;
623   ierr                  = PetscFree(pc_gamg->data);CHKERRQ(ierr);
624 
625   ierr = PetscInfo2(pc,"\t %D levels, grid complexity = %g\n",level+1,((double)nnztot)/nnz0);CHKERRQ(ierr);
626   pc_gamg->Nlevels = level + 1;
627   fine_level       = level;
628   ierr             = PCMGSetLevels(pc,pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
629 
630   /* simple setup */
631   if (!PETSC_TRUE) {
632     PC_MG_Levels **mglevels = mg->levels;
633     for (lidx=0,level=pc_gamg->Nlevels-1;
634          lidx<fine_level;
635          lidx++, level--) {
636       ierr = PCMGSetInterpolation(pc, lidx+1, Parr[level]);CHKERRQ(ierr);
637       ierr = KSPSetOperators(mglevels[lidx]->smoothd, Aarr[level], Aarr[level]);CHKERRQ(ierr);
638       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
639       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
640     }
641     ierr = KSPSetOperators(mglevels[fine_level]->smoothd, Aarr[0], Aarr[0]);CHKERRQ(ierr);
642 
643     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
644   } else if (pc_gamg->Nlevels > 1) { /* don't setup MG if one level */
645     /* set default smoothers & set operators */
646     for (lidx = 1, level = pc_gamg->Nlevels-2;
647          lidx <= fine_level;
648          lidx++, level--) {
649       KSP smoother;
650       PC  subpc;
651 
652       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
653       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
654 
655       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
656       /* set ops */
657       ierr = KSPSetOperators(smoother, Aarr[level], Aarr[level]);CHKERRQ(ierr);
658       ierr = PCMGSetInterpolation(pc, lidx, Parr[level+1]);CHKERRQ(ierr);
659 
660       /* set defaults */
661       ierr = KSPSetType(smoother, KSPCHEBYSHEV);CHKERRQ(ierr);
662 
663       /* set blocks for GASM smoother that uses the 'aggregates' */
664       if (pc_gamg->use_aggs_in_gasm) {
665         PetscInt sz;
666         IS       *is;
667 
668         sz   = nASMBlocksArr[level];
669         is   = ASMLocalIDsArr[level];
670         ierr = PCSetType(subpc, PCGASM);CHKERRQ(ierr);
671         ierr = PCGASMSetOverlap(subpc, 0);CHKERRQ(ierr);
672         if (sz==0) {
673           IS       is;
674           PetscInt my0,kk;
675           ierr = MatGetOwnershipRange(Aarr[level], &my0, &kk);CHKERRQ(ierr);
676           ierr = ISCreateGeneral(PETSC_COMM_SELF, 1, &my0, PETSC_COPY_VALUES, &is);CHKERRQ(ierr);
677           ierr = PCGASMSetSubdomains(subpc, 1, &is, NULL);CHKERRQ(ierr);
678           ierr = ISDestroy(&is);CHKERRQ(ierr);
679         } else {
680           PetscInt kk;
681           ierr = PCGASMSetSubdomains(subpc, sz, is, NULL);CHKERRQ(ierr);
682           for (kk=0; kk<sz; kk++) {
683             ierr = ISDestroy(&is[kk]);CHKERRQ(ierr);
684           }
685           ierr = PetscFree(is);CHKERRQ(ierr);
686         }
687         ASMLocalIDsArr[level] = NULL;
688         nASMBlocksArr[level]  = 0;
689         ierr                  = PCGASMSetType(subpc, PC_GASM_BASIC);CHKERRQ(ierr);
690       } else {
691         ierr = PCSetType(subpc, PCSOR);CHKERRQ(ierr);
692       }
693     }
694     {
695       /* coarse grid */
696       KSP smoother,*k2; PC subpc,pc2; PetscInt ii,first;
697       Mat Lmat = Aarr[(level=pc_gamg->Nlevels-1)]; lidx = 0;
698       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
699       ierr = KSPSetOperators(smoother, Lmat, Lmat);CHKERRQ(ierr);
700       ierr = KSPSetNormType(smoother, KSP_NORM_NONE);CHKERRQ(ierr);
701       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
702       ierr = PCSetType(subpc, PCBJACOBI);CHKERRQ(ierr);
703       ierr = PCSetUp(subpc);CHKERRQ(ierr);
704       ierr = PCBJacobiGetSubKSP(subpc,&ii,&first,&k2);CHKERRQ(ierr);
705       if (ii != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D is not one",ii);
706       ierr = KSPGetPC(k2[0],&pc2);CHKERRQ(ierr);
707       ierr = PCSetType(pc2, PCLU);CHKERRQ(ierr);
708       ierr = PCFactorSetShiftType(pc2,MAT_SHIFT_INBLOCKS);CHKERRQ(ierr);
709       ierr = KSPSetTolerances(k2[0],PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,1);CHKERRQ(ierr);
710       /* This flag gets reset by PCBJacobiGetSubKSP(), but our BJacobi really does the same algorithm everywhere (and in
711        * fact, all but one process will have zero dofs), so we reset the flag to avoid having PCView_BJacobi attempt to
712        * view every subdomain as though they were different. */
713       ((PC_BJacobi*)subpc->data)->same_local_solves = PETSC_TRUE;
714     }
715 
716     /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
717     ierr = PetscObjectOptionsBegin((PetscObject)pc);CHKERRQ(ierr);
718     ierr = PCSetFromOptions_MG(PetscOptionsObject,pc);CHKERRQ(ierr);
719     ierr = PetscOptionsEnd();CHKERRQ(ierr);
720     if (!mg->galerkin) SETERRQ(comm,PETSC_ERR_USER,"PCGAMG must use Galerkin for coarse operators.");
721     if (mg->galerkin == 1) mg->galerkin = 2;
722 
723     /* create cheby smoothers */
724     for (lidx = 1, level = pc_gamg->Nlevels-2; lidx <= fine_level; lidx++, level--) {
725       KSP       smoother;
726       PetscBool flag,flag2;
727       PC        subpc;
728 
729       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
730       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
731 
732       /* do my own cheby */
733       ierr = PetscObjectTypeCompare((PetscObject)smoother, KSPCHEBYSHEV, &flag);CHKERRQ(ierr);
734       if (0 && flag) {
735         PetscReal emax, emin;
736         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCJACOBI, &flag);CHKERRQ(ierr);
737         ierr = PetscObjectTypeCompare((PetscObject)subpc, PCSOR, &flag2);CHKERRQ(ierr);
738         if ((flag||flag2) && emaxs[level] > 0.0) emax=emaxs[level]; /* eigen estimate only for diagnal PC but lets acccept SOR because it is close and safe (always lower) */
739         else { /* eigen estimate 'emax' -- this is done in cheby */
740           KSP eksp;
741           Mat Lmat = Aarr[level];
742           Vec bb, xx;
743 
744           ierr = MatCreateVecs(Lmat, &bb, 0);CHKERRQ(ierr);
745           ierr = MatCreateVecs(Lmat, &xx, 0);CHKERRQ(ierr);
746           {
747             PetscRandom rctx;
748             ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
749             ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
750             ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
751             ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
752           }
753 
754           /* zeroing out BC rows -- needed for crazy matrices */
755           {
756             PetscInt    Istart,Iend,ncols,jj,Ii;
757             PetscScalar zero = 0.0;
758             ierr = MatGetOwnershipRange(Lmat, &Istart, &Iend);CHKERRQ(ierr);
759             for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
760               ierr = MatGetRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
761               if (ncols <= 1) {
762                 ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
763               }
764               ierr = MatRestoreRow(Lmat,Ii,&ncols,0,0);CHKERRQ(ierr);
765             }
766             ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
767             ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
768           }
769 
770           ierr = KSPCreate(comm, &eksp);CHKERRQ(ierr);
771           ierr = KSPSetTolerances(eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10);CHKERRQ(ierr);
772           ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
773           ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
774           ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
775           ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
776 
777           ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
778           ierr = KSPSetOperators(eksp, Lmat, Lmat);CHKERRQ(ierr);
779           ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
780 
781           /* set PC type to be same as smoother */
782           ierr = KSPSetPC(eksp, subpc);CHKERRQ(ierr);
783 
784           /* solve - keep stuff out of logging */
785           ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
786           ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
787           ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
788           ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
789           ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
790 
791           ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
792 
793           ierr = VecDestroy(&xx);CHKERRQ(ierr);
794           ierr = VecDestroy(&bb);CHKERRQ(ierr);
795           ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
796 
797 #if defined(PETSC_USE_INFO)
798           {
799             PetscInt N1;
800             ierr = MatGetSize(Aarr[level], &N1,NULL);CHKERRQ(ierr);
801             ierr = PetscInfo4(pc,"\t\t\t PC setup max eigen=%e min=%e on level %D (N=%D)\n",(double)emax,(double)emin,lidx,N1);CHKERRQ(ierr);
802           }
803 #endif
804         }
805         {
806           PetscInt N1, N0;
807           ierr = MatGetSize(Aarr[level], &N1, NULL);CHKERRQ(ierr);
808           ierr = MatGetSize(Aarr[level+1], &N0, NULL);CHKERRQ(ierr);
809           /* heuristic - is this crap? */
810           /* emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); */
811           emin  = emax * pc_gamg->eigtarget[0];
812           emax *= pc_gamg->eigtarget[1];
813         }
814         ierr = KSPChebyshevSetEigenvalues(smoother, emax, emin);CHKERRQ(ierr);
815       } /* setup checby flag */
816     } /* non-coarse levels */
817 
818     /* clean up */
819     for (level=1; level<pc_gamg->Nlevels; level++) {
820       ierr = MatDestroy(&Parr[level]);CHKERRQ(ierr);
821       ierr = MatDestroy(&Aarr[level]);CHKERRQ(ierr);
822     }
823 
824     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
825   } else {
826     KSP smoother;
827     ierr = PetscInfo(pc,"\tone level solver used (system is seen as DD). Using default solver.\n");
828     ierr = PCMGGetSmoother(pc, 0, &smoother);CHKERRQ(ierr);
829     ierr = KSPSetOperators(smoother, Aarr[0], Aarr[0]);CHKERRQ(ierr);
830     ierr = KSPSetType(smoother, KSPPREONLY);CHKERRQ(ierr);
831     ierr = PCSetUp_MG(pc);CHKERRQ(ierr);
832   }
833   PetscFunctionReturn(0);
834 }
835 
836 /* ------------------------------------------------------------------------- */
837 /*
838  PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
839    that was created with PCCreate_GAMG().
840 
841    Input Parameter:
842 .  pc - the preconditioner context
843 
844    Application Interface Routine: PCDestroy()
845 */
846 #undef __FUNCT__
847 #define __FUNCT__ "PCDestroy_GAMG"
848 PetscErrorCode PCDestroy_GAMG(PC pc)
849 {
850   PetscErrorCode ierr;
851   PC_MG          *mg     = (PC_MG*)pc->data;
852   PC_GAMG        *pc_gamg= (PC_GAMG*)mg->innerctx;
853 
854   PetscFunctionBegin;
855   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
856   if (pc_gamg->ops->destroy) {
857     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
858   }
859   ierr = PetscFree(pc_gamg->ops);CHKERRQ(ierr);
860   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
861   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
862   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
863   PetscFunctionReturn(0);
864 }
865 
866 
867 #undef __FUNCT__
868 #define __FUNCT__ "PCGAMGSetProcEqLim"
869 /*@
870    PCGAMGSetProcEqLim - Set number of equations to aim for on coarse grids via processor reduction.
871 
872    Logically Collective on PC
873 
874    Input Parameters:
875 +  pc - the preconditioner context
876 -  n - the number of equations
877 
878 
879    Options Database Key:
880 .  -pc_gamg_process_eq_limit <limit>
881 
882    Level: intermediate
883 
884    Concepts: Unstructured multigrid preconditioner
885 
886 .seealso: PCGAMGSetCoarseEqLim()
887 @*/
888 PetscErrorCode  PCGAMGSetProcEqLim(PC pc, PetscInt n)
889 {
890   PetscErrorCode ierr;
891 
892   PetscFunctionBegin;
893   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
894   ierr = PetscTryMethod(pc,"PCGAMGSetProcEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
895   PetscFunctionReturn(0);
896 }
897 
898 #undef __FUNCT__
899 #define __FUNCT__ "PCGAMGSetProcEqLim_GAMG"
900 static PetscErrorCode PCGAMGSetProcEqLim_GAMG(PC pc, PetscInt n)
901 {
902   PC_MG   *mg      = (PC_MG*)pc->data;
903   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
904 
905   PetscFunctionBegin;
906   if (n>0) pc_gamg->min_eq_proc = n;
907   PetscFunctionReturn(0);
908 }
909 
910 #undef __FUNCT__
911 #define __FUNCT__ "PCGAMGSetCoarseEqLim"
912 /*@
913    PCGAMGSetCoarseEqLim - Set max number of equations on coarse grids.
914 
915  Collective on PC
916 
917    Input Parameters:
918 +  pc - the preconditioner context
919 -  n - maximum number of equations to aim for
920 
921    Options Database Key:
922 .  -pc_gamg_coarse_eq_limit <limit>
923 
924    Level: intermediate
925 
926    Concepts: Unstructured multigrid preconditioner
927 
928 .seealso: PCGAMGSetProcEqLim()
929 @*/
930 PetscErrorCode PCGAMGSetCoarseEqLim(PC pc, PetscInt n)
931 {
932   PetscErrorCode ierr;
933 
934   PetscFunctionBegin;
935   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
936   ierr = PetscTryMethod(pc,"PCGAMGSetCoarseEqLim_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
937   PetscFunctionReturn(0);
938 }
939 
940 #undef __FUNCT__
941 #define __FUNCT__ "PCGAMGSetCoarseEqLim_GAMG"
942 static PetscErrorCode PCGAMGSetCoarseEqLim_GAMG(PC pc, PetscInt n)
943 {
944   PC_MG   *mg      = (PC_MG*)pc->data;
945   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
946 
947   PetscFunctionBegin;
948   if (n>0) pc_gamg->coarse_eq_limit = n;
949   PetscFunctionReturn(0);
950 }
951 
952 #undef __FUNCT__
953 #define __FUNCT__ "PCGAMGSetRepartitioning"
954 /*@
955    PCGAMGSetRepartitioning - Repartition the coarse grids
956 
957    Collective on PC
958 
959    Input Parameters:
960 +  pc - the preconditioner context
961 -  n - PETSC_TRUE or PETSC_FALSE
962 
963    Options Database Key:
964 .  -pc_gamg_repartition <true,false>
965 
966    Level: intermediate
967 
968    Concepts: Unstructured multigrid preconditioner
969 
970 .seealso: ()
971 @*/
972 PetscErrorCode PCGAMGSetRepartitioning(PC pc, PetscBool n)
973 {
974   PetscErrorCode ierr;
975 
976   PetscFunctionBegin;
977   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
978   ierr = PetscTryMethod(pc,"PCGAMGSetRepartitioning_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
979   PetscFunctionReturn(0);
980 }
981 
982 #undef __FUNCT__
983 #define __FUNCT__ "PCGAMGSetRepartitioning_GAMG"
984 static PetscErrorCode PCGAMGSetRepartitioning_GAMG(PC pc, PetscBool n)
985 {
986   PC_MG   *mg      = (PC_MG*)pc->data;
987   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
988 
989   PetscFunctionBegin;
990   pc_gamg->repart = n;
991   PetscFunctionReturn(0);
992 }
993 
994 #undef __FUNCT__
995 #define __FUNCT__ "PCGAMGSetReuseInterpolation"
996 /*@
997    PCGAMGSetReuseInterpolation - Reuse prolongation when rebuilding preconditioner
998 
999    Collective on PC
1000 
1001    Input Parameters:
1002 +  pc - the preconditioner context
1003 -  n - PETSC_TRUE or PETSC_FALSE
1004 
1005    Options Database Key:
1006 .  -pc_gamg_reuse_interpolation <true,false>
1007 
1008    Level: intermediate
1009 
1010    Concepts: Unstructured multigrid preconditioner
1011 
1012 .seealso: ()
1013 @*/
1014 PetscErrorCode PCGAMGSetReuseInterpolation(PC pc, PetscBool n)
1015 {
1016   PetscErrorCode ierr;
1017 
1018   PetscFunctionBegin;
1019   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1020   ierr = PetscTryMethod(pc,"PCGAMGSetReuseInterpolation_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1021   PetscFunctionReturn(0);
1022 }
1023 
1024 #undef __FUNCT__
1025 #define __FUNCT__ "PCGAMGSetReuseInterpolation_GAMG"
1026 static PetscErrorCode PCGAMGSetReuseInterpolation_GAMG(PC pc, PetscBool n)
1027 {
1028   PC_MG   *mg      = (PC_MG*)pc->data;
1029   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1030 
1031   PetscFunctionBegin;
1032   pc_gamg->reuse_prol = n;
1033   PetscFunctionReturn(0);
1034 }
1035 
1036 #undef __FUNCT__
1037 #define __FUNCT__ "PCGAMGSetUseASMAggs"
1038 /*@
1039    PCGAMGSetUseASMAggs -
1040 
1041    Collective on PC
1042 
1043    Input Parameters:
1044 .  pc - the preconditioner context
1045 
1046 
1047    Options Database Key:
1048 .  -pc_gamg_use_agg_gasm
1049 
1050    Level: intermediate
1051 
1052    Concepts: Unstructured multigrid preconditioner
1053 
1054 .seealso: ()
1055 @*/
1056 PetscErrorCode PCGAMGSetUseASMAggs(PC pc, PetscBool n)
1057 {
1058   PetscErrorCode ierr;
1059 
1060   PetscFunctionBegin;
1061   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1062   ierr = PetscTryMethod(pc,"PCGAMGSetUseASMAggs_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
1063   PetscFunctionReturn(0);
1064 }
1065 
1066 #undef __FUNCT__
1067 #define __FUNCT__ "PCGAMGSetUseASMAggs_GAMG"
1068 static PetscErrorCode PCGAMGSetUseASMAggs_GAMG(PC pc, PetscBool n)
1069 {
1070   PC_MG   *mg      = (PC_MG*)pc->data;
1071   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1072 
1073   PetscFunctionBegin;
1074   pc_gamg->use_aggs_in_gasm = n;
1075   PetscFunctionReturn(0);
1076 }
1077 
1078 #undef __FUNCT__
1079 #define __FUNCT__ "PCGAMGSetNlevels"
1080 /*@
1081    PCGAMGSetNlevels -  Sets the maximum number of levels PCGAMG will use
1082 
1083    Not collective on PC
1084 
1085    Input Parameters:
1086 +  pc - the preconditioner
1087 -  n - the maximum number of levels to use
1088 
1089    Options Database Key:
1090 .  -pc_mg_levels
1091 
1092    Level: intermediate
1093 
1094    Concepts: Unstructured multigrid preconditioner
1095 
1096 .seealso: ()
1097 @*/
1098 PetscErrorCode PCGAMGSetNlevels(PC pc, PetscInt n)
1099 {
1100   PetscErrorCode ierr;
1101 
1102   PetscFunctionBegin;
1103   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1104   ierr = PetscTryMethod(pc,"PCGAMGSetNlevels_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
1105   PetscFunctionReturn(0);
1106 }
1107 
1108 #undef __FUNCT__
1109 #define __FUNCT__ "PCGAMGSetNlevels_GAMG"
1110 static PetscErrorCode PCGAMGSetNlevels_GAMG(PC pc, PetscInt n)
1111 {
1112   PC_MG   *mg      = (PC_MG*)pc->data;
1113   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1114 
1115   PetscFunctionBegin;
1116   pc_gamg->Nlevels = n;
1117   PetscFunctionReturn(0);
1118 }
1119 
1120 #undef __FUNCT__
1121 #define __FUNCT__ "PCGAMGSetThreshold"
1122 /*@
1123    PCGAMGSetThreshold - Relative threshold to use for dropping edges in aggregation graph
1124 
1125    Not collective on PC
1126 
1127    Input Parameters:
1128 +  pc - the preconditioner context
1129 -  threshold - the threshold value, 0.0 means keep all nonzero entries in the graph; negative means keep even zero entries in the graph
1130 
1131    Options Database Key:
1132 .  -pc_gamg_threshold <threshold>
1133 
1134    Level: intermediate
1135 
1136    Concepts: Unstructured multigrid preconditioner
1137 
1138 .seealso: ()
1139 @*/
1140 PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
1141 {
1142   PetscErrorCode ierr;
1143 
1144   PetscFunctionBegin;
1145   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1146   ierr = PetscTryMethod(pc,"PCGAMGSetThreshold_C",(PC,PetscReal),(pc,n));CHKERRQ(ierr);
1147   PetscFunctionReturn(0);
1148 }
1149 
1150 #undef __FUNCT__
1151 #define __FUNCT__ "PCGAMGSetThreshold_GAMG"
1152 static PetscErrorCode PCGAMGSetThreshold_GAMG(PC pc, PetscReal n)
1153 {
1154   PC_MG   *mg      = (PC_MG*)pc->data;
1155   PC_GAMG *pc_gamg = (PC_GAMG*)mg->innerctx;
1156 
1157   PetscFunctionBegin;
1158   pc_gamg->threshold = n;
1159   PetscFunctionReturn(0);
1160 }
1161 
1162 #undef __FUNCT__
1163 #define __FUNCT__ "PCGAMGSetType"
1164 /*@
1165    PCGAMGSetType - Set solution method
1166 
1167    Collective on PC
1168 
1169    Input Parameters:
1170 +  pc - the preconditioner context
1171 -  type - PCGAMGAGG, PCGAMGGEO, or PCGAMGCLASSICAL
1172 
1173    Options Database Key:
1174 .  -pc_gamg_type <agg,geo,classical>
1175 
1176    Level: intermediate
1177 
1178    Concepts: Unstructured multigrid preconditioner
1179 
1180 .seealso: PCGAMGGetType(), PCGAMG
1181 @*/
1182 PetscErrorCode PCGAMGSetType(PC pc, PCGAMGType type)
1183 {
1184   PetscErrorCode ierr;
1185 
1186   PetscFunctionBegin;
1187   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1188   ierr = PetscTryMethod(pc,"PCGAMGSetType_C",(PC,PCGAMGType),(pc,type));CHKERRQ(ierr);
1189   PetscFunctionReturn(0);
1190 }
1191 
1192 #undef __FUNCT__
1193 #define __FUNCT__ "PCGAMGGetType"
1194 /*@
1195    PCGAMGGetType - Get solution method
1196 
1197    Collective on PC
1198 
1199    Input Parameter:
1200 .  pc - the preconditioner context
1201 
1202    Output Parameter:
1203 .  type - the type of algorithm used
1204 
1205    Level: intermediate
1206 
1207    Concepts: Unstructured multigrid preconditioner
1208 
1209 .seealso: PCGAMGSetType(), PCGAMGType
1210 @*/
1211 PetscErrorCode PCGAMGGetType(PC pc, PCGAMGType *type)
1212 {
1213   PetscErrorCode ierr;
1214 
1215   PetscFunctionBegin;
1216   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
1217   ierr = PetscUseMethod(pc,"PCGAMGGetType_C",(PC,PCGAMGType*),(pc,type));CHKERRQ(ierr);
1218   PetscFunctionReturn(0);
1219 }
1220 
1221 #undef __FUNCT__
1222 #define __FUNCT__ "PCGAMGGetType_GAMG"
1223 static PetscErrorCode PCGAMGGetType_GAMG(PC pc, PCGAMGType *type)
1224 {
1225   PC_MG          *mg      = (PC_MG*)pc->data;
1226   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1227 
1228   PetscFunctionBegin;
1229   *type = pc_gamg->type;
1230   PetscFunctionReturn(0);
1231 }
1232 
1233 #undef __FUNCT__
1234 #define __FUNCT__ "PCGAMGSetType_GAMG"
1235 static PetscErrorCode PCGAMGSetType_GAMG(PC pc, PCGAMGType type)
1236 {
1237   PetscErrorCode ierr,(*r)(PC);
1238   PC_MG          *mg      = (PC_MG*)pc->data;
1239   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1240 
1241   PetscFunctionBegin;
1242   pc_gamg->type = type;
1243   ierr = PetscFunctionListFind(GAMGList,type,&r);CHKERRQ(ierr);
1244   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unknown GAMG type %s given",type);
1245   if (pc_gamg->ops->destroy) {
1246     ierr = (*pc_gamg->ops->destroy)(pc);CHKERRQ(ierr);
1247     ierr = PetscMemzero(pc_gamg->ops,sizeof(struct _PCGAMGOps));CHKERRQ(ierr);
1248     pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
1249     /* cleaning up common data in pc_gamg - this should disapear someday */
1250     pc_gamg->data_cell_cols = 0;
1251     pc_gamg->data_cell_rows = 0;
1252     pc_gamg->orig_data_cell_cols = 0;
1253     pc_gamg->orig_data_cell_rows = 0;
1254     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1255     pc_gamg->data_sz = 0;
1256   }
1257   ierr = PetscFree(pc_gamg->gamg_type_name);CHKERRQ(ierr);
1258   ierr = PetscStrallocpy(type,&pc_gamg->gamg_type_name);CHKERRQ(ierr);
1259   ierr = (*r)(pc);CHKERRQ(ierr);
1260   PetscFunctionReturn(0);
1261 }
1262 
1263 #undef __FUNCT__
1264 #define __FUNCT__ "PCView_GAMG"
1265 static PetscErrorCode PCView_GAMG(PC pc,PetscViewer viewer)
1266 {
1267   PetscErrorCode ierr;
1268   PC_MG          *mg      = (PC_MG*)pc->data;
1269   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1270 
1271   PetscFunctionBegin;
1272   ierr = PetscViewerASCIIPrintf(viewer,"    GAMG specific options\n");CHKERRQ(ierr);
1273   ierr = PetscViewerASCIIPrintf(viewer,"      Threshold for dropping small values from graph %g\n",(double)pc_gamg->threshold);CHKERRQ(ierr);
1274   if (pc_gamg->ops->view) {
1275     ierr = (*pc_gamg->ops->view)(pc,viewer);CHKERRQ(ierr);
1276   }
1277   PetscFunctionReturn(0);
1278 }
1279 
1280 #undef __FUNCT__
1281 #define __FUNCT__ "PCSetFromOptions_GAMG"
1282 PetscErrorCode PCSetFromOptions_GAMG(PetscOptions *PetscOptionsObject,PC pc)
1283 {
1284   PetscErrorCode ierr;
1285   PC_MG          *mg      = (PC_MG*)pc->data;
1286   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1287   PetscBool      flag;
1288   PetscInt       two   = 2;
1289   MPI_Comm       comm;
1290 
1291   PetscFunctionBegin;
1292   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1293   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG options");CHKERRQ(ierr);
1294   {
1295     char tname[256];
1296     ierr = PetscOptionsFList("-pc_gamg_type","Type of AMG method","PCGAMGSetType",GAMGList, pc_gamg->gamg_type_name, tname, sizeof(tname), &flag);CHKERRQ(ierr);
1297     if (flag) {
1298       ierr = PCGAMGSetType(pc,tname);CHKERRQ(ierr);
1299     }
1300     ierr = PetscOptionsBool("-pc_gamg_repartition","Repartion coarse grids","PCGAMGRepartitioning",pc_gamg->repart,&pc_gamg->repart,NULL);CHKERRQ(ierr);
1301     ierr = PetscOptionsBool("-pc_gamg_reuse_interpolation","Reuse prolongation operator","PCGAMGReuseInterpolation",pc_gamg->reuse_prol,&pc_gamg->reuse_prol,NULL);CHKERRQ(ierr);
1302     ierr = PetscOptionsBool("-pc_gamg_use_agg_gasm","Use aggregation agragates for GASM smoother","PCGAMGUseASMAggs",pc_gamg->use_aggs_in_gasm,&pc_gamg->use_aggs_in_gasm,NULL);CHKERRQ(ierr);
1303     ierr = PetscOptionsInt("-pc_gamg_process_eq_limit","Limit (goal) on number of equations per process on coarse grids","PCGAMGSetProcEqLim",pc_gamg->min_eq_proc,&pc_gamg->min_eq_proc,NULL);CHKERRQ(ierr);
1304     ierr = PetscOptionsInt("-pc_gamg_coarse_eq_limit","Limit on number of equations for the coarse grid","PCGAMGSetCoarseEqLim",pc_gamg->coarse_eq_limit,&pc_gamg->coarse_eq_limit,NULL);CHKERRQ(ierr);
1305     ierr = PetscOptionsReal("-pc_gamg_threshold","Relative threshold to use for dropping edges in aggregation graph","PCGAMGSetThreshold",pc_gamg->threshold,&pc_gamg->threshold,&flag);CHKERRQ(ierr);
1306     ierr = PetscOptionsRealArray("-pc_gamg_eigtarget","Target eigenvalue range as fraction of estimated maximum eigenvalue","PCGAMGSetEigTarget",pc_gamg->eigtarget,&two,NULL);CHKERRQ(ierr);
1307     ierr = PetscOptionsInt("-pc_mg_levels","Set number of MG levels","PCGAMGSetNlevels",pc_gamg->Nlevels,&pc_gamg->Nlevels,NULL);CHKERRQ(ierr);
1308 
1309     /* set options for subtype */
1310     if (pc_gamg->ops->setfromoptions) {ierr = (*pc_gamg->ops->setfromoptions)(PetscOptionsObject,pc);CHKERRQ(ierr);}
1311   }
1312   ierr = PetscOptionsTail();CHKERRQ(ierr);
1313   PetscFunctionReturn(0);
1314 }
1315 
1316 /* -------------------------------------------------------------------------- */
1317 /*MC
1318      PCGAMG - Geometric algebraic multigrid (AMG) preconditioner
1319 
1320    Options Database Keys:
1321    Multigrid options(inherited)
1322 +  -pc_mg_cycles <v>: v or w (PCMGSetCycleType())
1323 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (PCMGSetNumberSmoothUp)
1324 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (PCMGSetNumberSmoothDown)
1325 -  -pc_mg_type <multiplicative>: (one of) additive multiplicative full kascade
1326 
1327 
1328   Notes: In order to obtain good performance for PCGAMG for vector valued problems you must
1329 $       Call MatSetBlockSize() to indicate the number of degrees of freedom per grid point
1330 $       Call MatSetNearNullSpace() (or PCSetCoordinates() if solving the equations of elasticity) to indicate the near null space of the operator
1331 $       See the Users Manual Chapter 4 for more details
1332 
1333   Level: intermediate
1334 
1335   Concepts: algebraic multigrid
1336 
1337 .seealso:  PCCreate(), PCSetType(), MatSetBlockSize(), PCMGType, PCSetCoordinates(), MatSetNearNullSpace(), PCGAMGSetType(), PCGAMGAGG, PCGAMGGEO, PCGAMGCLASSICAL, PCGAMGSetProcEqLim(),
1338            PCGAMGSetCoarseEqLim(), PCGAMGSetRepartitioning(), PCGAMGRegister(), PCGAMGSetReuseInterpolation(), PCGAMGSetUseASMAggs(), PCGAMGSetNlevels(), PCGAMGSetThreshold(), PCGAMGGetType()
1339 M*/
1340 
1341 #undef __FUNCT__
1342 #define __FUNCT__ "PCCreate_GAMG"
1343 PETSC_EXTERN PetscErrorCode PCCreate_GAMG(PC pc)
1344 {
1345   PetscErrorCode ierr;
1346   PC_GAMG        *pc_gamg;
1347   PC_MG          *mg;
1348 
1349   PetscFunctionBegin;
1350   /* register AMG type */
1351   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1352 
1353   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
1354   ierr = PCSetType(pc, PCMG);CHKERRQ(ierr);
1355   ierr = PetscObjectChangeTypeName((PetscObject)pc, PCGAMG);CHKERRQ(ierr);
1356 
1357   /* create a supporting struct and attach it to pc */
1358   ierr         = PetscNewLog(pc,&pc_gamg);CHKERRQ(ierr);
1359   mg           = (PC_MG*)pc->data;
1360   mg->galerkin = 2;             /* Use Galerkin, but it is computed externally from PCMG by GAMG code */
1361   mg->innerctx = pc_gamg;
1362 
1363   ierr = PetscNewLog(pc,&pc_gamg->ops);CHKERRQ(ierr);
1364 
1365   pc_gamg->setup_count = 0;
1366   /* these should be in subctx but repartitioning needs simple arrays */
1367   pc_gamg->data_sz = 0;
1368   pc_gamg->data    = 0;
1369 
1370   /* overwrite the pointers of PCMG by the functions of base class PCGAMG */
1371   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
1372   pc->ops->setup          = PCSetUp_GAMG;
1373   pc->ops->reset          = PCReset_GAMG;
1374   pc->ops->destroy        = PCDestroy_GAMG;
1375   mg->view                = PCView_GAMG;
1376 
1377   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetProcEqLim_C",PCGAMGSetProcEqLim_GAMG);CHKERRQ(ierr);
1378   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetCoarseEqLim_C",PCGAMGSetCoarseEqLim_GAMG);CHKERRQ(ierr);
1379   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetRepartitioning_C",PCGAMGSetRepartitioning_GAMG);CHKERRQ(ierr);
1380   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetReuseInterpolation_C",PCGAMGSetReuseInterpolation_GAMG);CHKERRQ(ierr);
1381   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetUseASMAggs_C",PCGAMGSetUseASMAggs_GAMG);CHKERRQ(ierr);
1382   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetThreshold_C",PCGAMGSetThreshold_GAMG);CHKERRQ(ierr);
1383   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetType_C",PCGAMGSetType_GAMG);CHKERRQ(ierr);
1384   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGGetType_C",PCGAMGGetType_GAMG);CHKERRQ(ierr);
1385   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCGAMGSetNlevels_C",PCGAMGSetNlevels_GAMG);CHKERRQ(ierr);
1386   pc_gamg->repart           = PETSC_FALSE;
1387   pc_gamg->reuse_prol       = PETSC_FALSE;
1388   pc_gamg->use_aggs_in_gasm = PETSC_FALSE;
1389   pc_gamg->min_eq_proc      = 50;
1390   pc_gamg->coarse_eq_limit  = 50;
1391   pc_gamg->threshold        = 0.;
1392   pc_gamg->Nlevels          = GAMG_MAXLEVELS;
1393   pc_gamg->emax_id          = -1;
1394   pc_gamg->firstCoarsen     = PETSC_FALSE;
1395   pc_gamg->eigtarget[0]     = 0.05;
1396   pc_gamg->eigtarget[1]     = 1.05;
1397   pc_gamg->ops->createlevel = PCGAMGCreateLevel_GAMG;
1398 
1399   /* PCSetUp_GAMG assumes that the type has been set, so set it to the default now */
1400   ierr = PCGAMGSetType(pc,PCGAMGAGG);CHKERRQ(ierr);
1401   PetscFunctionReturn(0);
1402 }
1403 
1404 #undef __FUNCT__
1405 #define __FUNCT__ "PCGAMGInitializePackage"
1406 /*@C
1407  PCGAMGInitializePackage - This function initializes everything in the PCGAMG package. It is called
1408     from PetscDLLibraryRegister() when using dynamic libraries, and on the first call to PCCreate_GAMG()
1409     when using static libraries.
1410 
1411  Level: developer
1412 
1413  .keywords: PC, PCGAMG, initialize, package
1414  .seealso: PetscInitialize()
1415 @*/
1416 PetscErrorCode PCGAMGInitializePackage(void)
1417 {
1418   PetscErrorCode ierr;
1419 
1420   PetscFunctionBegin;
1421   if (PCGAMGPackageInitialized) PetscFunctionReturn(0);
1422   PCGAMGPackageInitialized = PETSC_TRUE;
1423   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGGEO,PCCreateGAMG_GEO);CHKERRQ(ierr);
1424   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGAGG,PCCreateGAMG_AGG);CHKERRQ(ierr);
1425   ierr = PetscFunctionListAdd(&GAMGList,PCGAMGCLASSICAL,PCCreateGAMG_Classical);CHKERRQ(ierr);
1426   ierr = PetscRegisterFinalize(PCGAMGFinalizePackage);CHKERRQ(ierr);
1427 
1428   /* general events */
1429   ierr = PetscLogEventRegister("PCGAMGGraph_AGG", 0, &PC_GAMGGraph_AGG);CHKERRQ(ierr);
1430   ierr = PetscLogEventRegister("PCGAMGGraph_GEO", PC_CLASSID, &PC_GAMGGraph_GEO);CHKERRQ(ierr);
1431   ierr = PetscLogEventRegister("PCGAMGCoarse_AGG", PC_CLASSID, &PC_GAMGCoarsen_AGG);CHKERRQ(ierr);
1432   ierr = PetscLogEventRegister("PCGAMGCoarse_GEO", PC_CLASSID, &PC_GAMGCoarsen_GEO);CHKERRQ(ierr);
1433   ierr = PetscLogEventRegister("PCGAMGProl_AGG", PC_CLASSID, &PC_GAMGProlongator_AGG);CHKERRQ(ierr);
1434   ierr = PetscLogEventRegister("PCGAMGProl_GEO", PC_CLASSID, &PC_GAMGProlongator_GEO);CHKERRQ(ierr);
1435   ierr = PetscLogEventRegister("PCGAMGPOpt_AGG", PC_CLASSID, &PC_GAMGOptProlongator_AGG);CHKERRQ(ierr);
1436 
1437 #if defined PETSC_GAMG_USE_LOG
1438   ierr = PetscLogEventRegister("GAMG: createProl", PC_CLASSID, &petsc_gamg_setup_events[SET1]);CHKERRQ(ierr);
1439   ierr = PetscLogEventRegister("  Graph", PC_CLASSID, &petsc_gamg_setup_events[GRAPH]);CHKERRQ(ierr);
1440   /* PetscLogEventRegister("    G.Mat", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_MAT]); */
1441   /* PetscLogEventRegister("    G.Filter", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_FILTER]); */
1442   /* PetscLogEventRegister("    G.Square", PC_CLASSID, &petsc_gamg_setup_events[GRAPH_SQR]); */
1443   ierr = PetscLogEventRegister("  MIS/Agg", PC_CLASSID, &petsc_gamg_setup_events[SET4]);CHKERRQ(ierr);
1444   ierr = PetscLogEventRegister("  geo: growSupp", PC_CLASSID, &petsc_gamg_setup_events[SET5]);CHKERRQ(ierr);
1445   ierr = PetscLogEventRegister("  geo: triangle", PC_CLASSID, &petsc_gamg_setup_events[SET6]);CHKERRQ(ierr);
1446   ierr = PetscLogEventRegister("    search&set", PC_CLASSID, &petsc_gamg_setup_events[FIND_V]);CHKERRQ(ierr);
1447   ierr = PetscLogEventRegister("  SA: col data", PC_CLASSID, &petsc_gamg_setup_events[SET7]);CHKERRQ(ierr);
1448   ierr = PetscLogEventRegister("  SA: frmProl0", PC_CLASSID, &petsc_gamg_setup_events[SET8]);CHKERRQ(ierr);
1449   ierr = PetscLogEventRegister("  SA: smooth", PC_CLASSID, &petsc_gamg_setup_events[SET9]);CHKERRQ(ierr);
1450   ierr = PetscLogEventRegister("GAMG: partLevel", PC_CLASSID, &petsc_gamg_setup_events[SET2]);CHKERRQ(ierr);
1451   ierr = PetscLogEventRegister("  repartition", PC_CLASSID, &petsc_gamg_setup_events[SET12]);CHKERRQ(ierr);
1452   ierr = PetscLogEventRegister("  Invert-Sort", PC_CLASSID, &petsc_gamg_setup_events[SET13]);CHKERRQ(ierr);
1453   ierr = PetscLogEventRegister("  Move A", PC_CLASSID, &petsc_gamg_setup_events[SET14]);CHKERRQ(ierr);
1454   ierr = PetscLogEventRegister("  Move P", PC_CLASSID, &petsc_gamg_setup_events[SET15]);CHKERRQ(ierr);
1455 
1456   /* PetscLogEventRegister(" PL move data", PC_CLASSID, &petsc_gamg_setup_events[SET13]); */
1457   /* PetscLogEventRegister("GAMG: fix", PC_CLASSID, &petsc_gamg_setup_events[SET10]); */
1458   /* PetscLogEventRegister("GAMG: set levels", PC_CLASSID, &petsc_gamg_setup_events[SET11]); */
1459   /* create timer stages */
1460 #if defined GAMG_STAGES
1461   {
1462     char     str[32];
1463     PetscInt lidx;
1464     sprintf(str,"MG Level %d (finest)",0);
1465     ierr = PetscLogStageRegister(str, &gamg_stages[0]);CHKERRQ(ierr);
1466     for (lidx=1; lidx<9; lidx++) {
1467       sprintf(str,"MG Level %d",lidx);
1468       ierr = PetscLogStageRegister(str, &gamg_stages[lidx]);CHKERRQ(ierr);
1469     }
1470   }
1471 #endif
1472 #endif
1473   PetscFunctionReturn(0);
1474 }
1475 
1476 #undef __FUNCT__
1477 #define __FUNCT__ "PCGAMGFinalizePackage"
1478 /*@C
1479  PCGAMGFinalizePackage - This function frees everything from the PCGAMG package. It is
1480     called from PetscFinalize() automatically.
1481 
1482  Level: developer
1483 
1484  .keywords: Petsc, destroy, package
1485  .seealso: PetscFinalize()
1486 @*/
1487 PetscErrorCode PCGAMGFinalizePackage(void)
1488 {
1489   PetscErrorCode ierr;
1490 
1491   PetscFunctionBegin;
1492   PCGAMGPackageInitialized = PETSC_FALSE;
1493   ierr = PetscFunctionListDestroy(&GAMGList);CHKERRQ(ierr);
1494   PetscFunctionReturn(0);
1495 }
1496 
1497 #undef __FUNCT__
1498 #define __FUNCT__ "PCGAMGRegister"
1499 /*@C
1500  PCGAMGRegister - Register a PCGAMG implementation.
1501 
1502  Input Parameters:
1503  + type - string that will be used as the name of the GAMG type.
1504  - create - function for creating the gamg context.
1505 
1506   Level: advanced
1507 
1508  .seealso: PCGAMGType, PCGAMG, PCGAMGSetType()
1509 @*/
1510 PetscErrorCode PCGAMGRegister(PCGAMGType type, PetscErrorCode (*create)(PC))
1511 {
1512   PetscErrorCode ierr;
1513 
1514   PetscFunctionBegin;
1515   ierr = PCGAMGInitializePackage();CHKERRQ(ierr);
1516   ierr = PetscFunctionListAdd(&GAMGList,type,create);CHKERRQ(ierr);
1517   PetscFunctionReturn(0);
1518 }
1519 
1520