xref: /petsc/src/ksp/pc/impls/gamg/agg.c (revision b7cbab4ec1e3237e6d75c8da14ec4f01516e422d)
1 /*
2  GAMG geometric-algebric multiogrid PC - Mark Adams 2011
3  */
4 
5 #include <../src/ksp/pc/impls/gamg/gamg.h>        /*I "petscpc.h" I*/
6 #include <petsc-private/kspimpl.h>
7 
8 #include <petscblaslapack.h>
9 
10 typedef struct {
11   PetscInt  nsmooths;
12   PetscBool sym_graph;
13   PetscBool square_graph;
14 } PC_GAMG_AGG;
15 
16 #undef __FUNCT__
17 #define __FUNCT__ "PCGAMGSetNSmooths"
18 /*@
19    PCGAMGSetNSmooths - Set number of smoothing steps (1 is typical)
20 
21    Not Collective on PC
22 
23    Input Parameters:
24 .  pc - the preconditioner context
25 
26    Options Database Key:
27 .  -pc_gamg_agg_nsmooths
28 
29    Level: intermediate
30 
31    Concepts: Aggregation AMG preconditioner
32 
33 .seealso: ()
34 @*/
35 PetscErrorCode PCGAMGSetNSmooths(PC pc, PetscInt n)
36 {
37   PetscErrorCode ierr;
38 
39   PetscFunctionBegin;
40   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
41   ierr = PetscTryMethod(pc,"PCGAMGSetNSmooths_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
42   PetscFunctionReturn(0);
43 }
44 
45 #undef __FUNCT__
46 #define __FUNCT__ "PCGAMGSetNSmooths_GAMG"
47 PetscErrorCode PCGAMGSetNSmooths_GAMG(PC pc, PetscInt n)
48 {
49   PC_MG       *mg          = (PC_MG*)pc->data;
50   PC_GAMG     *pc_gamg     = (PC_GAMG*)mg->innerctx;
51   PC_GAMG_AGG *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
52 
53   PetscFunctionBegin;
54   pc_gamg_agg->nsmooths = n;
55   PetscFunctionReturn(0);
56 }
57 
58 #undef __FUNCT__
59 #define __FUNCT__ "PCGAMGSetSymGraph"
60 /*@
61    PCGAMGSetSymGraph -
62 
63    Not Collective on PC
64 
65    Input Parameters:
66 .  pc - the preconditioner context
67 
68    Options Database Key:
69 .  -pc_gamg_sym_graph
70 
71    Level: intermediate
72 
73    Concepts: Aggregation AMG preconditioner
74 
75 .seealso: ()
76 @*/
77 PetscErrorCode PCGAMGSetSymGraph(PC pc, PetscBool n)
78 {
79   PetscErrorCode ierr;
80 
81   PetscFunctionBegin;
82   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
83   ierr = PetscTryMethod(pc,"PCGAMGSetSymGraph_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
84   PetscFunctionReturn(0);
85 }
86 
87 #undef __FUNCT__
88 #define __FUNCT__ "PCGAMGSetSymGraph_GAMG"
89 PetscErrorCode PCGAMGSetSymGraph_GAMG(PC pc, PetscBool n)
90 {
91   PC_MG       *mg          = (PC_MG*)pc->data;
92   PC_GAMG     *pc_gamg     = (PC_GAMG*)mg->innerctx;
93   PC_GAMG_AGG *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
94 
95   PetscFunctionBegin;
96   pc_gamg_agg->sym_graph = n;
97   PetscFunctionReturn(0);
98 }
99 
100 #undef __FUNCT__
101 #define __FUNCT__ "PCGAMGSetSquareGraph"
102 /*@
103    PCGAMGSetSquareGraph -
104 
105    Not Collective on PC
106 
107    Input Parameters:
108 .  pc - the preconditioner context
109 
110    Options Database Key:
111 .  -pc_gamg_square_graph
112 
113    Level: intermediate
114 
115    Concepts: Aggregation AMG preconditioner
116 
117 .seealso: ()
118 @*/
119 PetscErrorCode PCGAMGSetSquareGraph(PC pc, PetscBool n)
120 {
121   PetscErrorCode ierr;
122 
123   PetscFunctionBegin;
124   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
125   ierr = PetscTryMethod(pc,"PCGAMGSetSquareGraph_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
126   PetscFunctionReturn(0);
127 }
128 
129 #undef __FUNCT__
130 #define __FUNCT__ "PCGAMGSetSquareGraph_GAMG"
131 PetscErrorCode PCGAMGSetSquareGraph_GAMG(PC pc, PetscBool n)
132 {
133   PC_MG       *mg          = (PC_MG*)pc->data;
134   PC_GAMG     *pc_gamg     = (PC_GAMG*)mg->innerctx;
135   PC_GAMG_AGG *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
136 
137   PetscFunctionBegin;
138   pc_gamg_agg->square_graph = n;
139   PetscFunctionReturn(0);
140 }
141 
142 /* -------------------------------------------------------------------------- */
143 /*
144    PCSetFromOptions_GAMG_AGG
145 
146   Input Parameter:
147    . pc -
148 */
149 #undef __FUNCT__
150 #define __FUNCT__ "PCSetFromOptions_GAMG_AGG"
151 PetscErrorCode PCSetFromOptions_GAMG_AGG(PC pc)
152 {
153   PetscErrorCode ierr;
154   PC_MG          *mg          = (PC_MG*)pc->data;
155   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
156   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
157   PetscBool      flag;
158 
159   PetscFunctionBegin;
160 
161   ierr = PetscOptionsHead("GAMG-AGG options");CHKERRQ(ierr);
162   {
163     /* -pc_gamg_agg_nsmooths */
164     pc_gamg_agg->nsmooths = 0;
165 
166     ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths",
167                            "smoothing steps for smoothed aggregation, usually 1 (0)",
168                            "PCGAMGSetNSmooths",
169                            pc_gamg_agg->nsmooths,
170                            &pc_gamg_agg->nsmooths,
171                            &flag);CHKERRQ(ierr);
172 
173     /* -pc_gamg_sym_graph */
174     pc_gamg_agg->sym_graph = PETSC_FALSE;
175 
176     ierr = PetscOptionsBool("-pc_gamg_sym_graph",
177                             "Set for asymmetric matrices",
178                             "PCGAMGSetSymGraph",
179                             pc_gamg_agg->sym_graph,
180                             &pc_gamg_agg->sym_graph,
181                             &flag);CHKERRQ(ierr);
182 
183     /* -pc_gamg_square_graph */
184     pc_gamg_agg->square_graph = PETSC_TRUE;
185 
186     ierr = PetscOptionsBool("-pc_gamg_square_graph",
187                             "For faster coarsening and lower coarse grid complexity",
188                             "PCGAMGSetSquareGraph",
189                             pc_gamg_agg->square_graph,
190                             &pc_gamg_agg->square_graph,
191                             &flag);CHKERRQ(ierr);
192   }
193   ierr = PetscOptionsTail();CHKERRQ(ierr);
194   PetscFunctionReturn(0);
195 }
196 
197 /* -------------------------------------------------------------------------- */
198 /*
199    PCDestroy_AGG
200 
201   Input Parameter:
202    . pc -
203 */
204 #undef __FUNCT__
205 #define __FUNCT__ "PCDestroy_AGG"
206 PetscErrorCode PCDestroy_AGG(PC pc)
207 {
208   PetscErrorCode ierr;
209   PC_MG          *mg          = (PC_MG*)pc->data;
210   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
211   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
212 
213   PetscFunctionBegin;
214   if (pc_gamg_agg) {
215     ierr        = PetscFree(pc_gamg_agg);CHKERRQ(ierr);
216     pc_gamg_agg = 0;
217   }
218 
219   /* call base class */
220   ierr = PCDestroy_GAMG(pc);CHKERRQ(ierr);
221   PetscFunctionReturn(0);
222 }
223 
224 /* -------------------------------------------------------------------------- */
225 /*
226    PCSetCoordinates_AGG
227      - collective
228 
229    Input Parameter:
230    . pc - the preconditioner context
231    . ndm - dimesion of data (used for dof/vertex for Stokes)
232    . a_nloc - number of vertices local
233    . coords - [a_nloc][ndm] - interleaved coordinate data: {x_0, y_0, z_0, x_1, y_1, ...}
234 */
235 
236 #undef __FUNCT__
237 #define __FUNCT__ "PCSetCoordinates_AGG"
238 static PetscErrorCode PCSetCoordinates_AGG(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
239 {
240   PC_MG          *mg      = (PC_MG*)pc->data;
241   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
242   PetscErrorCode ierr;
243   PetscInt       arrsz,kk,ii,jj,nloc,ndatarows,ndf;
244   Mat            mat = pc->pmat;
245 
246   PetscFunctionBegin;
247   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
248   PetscValidHeaderSpecific(mat,MAT_CLASSID,1);
249   nloc = a_nloc;
250 
251   /* SA: null space vectors */
252   ierr = MatGetBlockSize(mat, &ndf);CHKERRQ(ierr); /* this does not work for Stokes */
253   if (coords && ndf==1) pc_gamg->data_cell_cols = 1; /* scalar w/ coords and SA (not needed) */
254   else if (coords) {
255     if (ndm > ndf) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"degrees of motion %d > block size %d",ndm,ndf);
256     pc_gamg->data_cell_cols = (ndm==2 ? 3 : 6); /* displacement elasticity */
257     if (ndm != ndf) {
258       if (pc_gamg->data_cell_cols != ndf) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Don't know how to create null space for ndm=%d, ndf=%d.  Use MatSetNearNullSpace.",ndm,ndf);
259     }
260   } else pc_gamg->data_cell_cols = ndf; /* no data, force SA with constant null space vectors */
261   pc_gamg->data_cell_rows = ndatarows = ndf;
262   if (pc_gamg->data_cell_cols <= 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"pc_gamg->data_cell_cols %D <= 0",pc_gamg->data_cell_cols);
263   arrsz = nloc*pc_gamg->data_cell_rows*pc_gamg->data_cell_cols;
264 
265   /* create data - syntactic sugar that should be refactored at some point */
266   if (pc_gamg->data==0 || (pc_gamg->data_sz != arrsz)) {
267     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
268     ierr = PetscMalloc((arrsz+1)*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
269   }
270   /* copy data in - column oriented */
271   for (kk=0; kk<nloc; kk++) {
272     const PetscInt M     = nloc*pc_gamg->data_cell_rows; /* stride into data */
273     PetscReal      *data = &pc_gamg->data[kk*ndatarows]; /* start of cell */
274     if (pc_gamg->data_cell_cols==1) *data = 1.0;
275     else {
276       /* translational modes */
277       for (ii=0;ii<ndatarows;ii++) {
278         for (jj=0;jj<ndatarows;jj++) {
279           if (ii==jj)data[ii*M + jj] = 1.0;
280           else data[ii*M + jj] = 0.0;
281         }
282       }
283 
284       /* rotational modes */
285       if (coords) {
286         if (ndm == 2) {
287           data   += 2*M;
288           data[0] = -coords[2*kk+1];
289           data[1] =  coords[2*kk];
290         } else {
291           data   += 3*M;
292           data[0] = 0.0;             data[M+0] =  coords[3*kk+2]; data[2*M+0] = -coords[3*kk+1];
293           data[1] = -coords[3*kk+2]; data[M+1] = 0.0;             data[2*M+1] =  coords[3*kk];
294           data[2] =  coords[3*kk+1]; data[M+2] = -coords[3*kk];   data[2*M+2] = 0.0;
295         }
296       }
297     }
298   }
299 
300   pc_gamg->data_sz = arrsz;
301   PetscFunctionReturn(0);
302 }
303 
304 typedef PetscInt NState;
305 static const NState NOT_DONE=-2;
306 static const NState DELETED =-1;
307 static const NState REMOVED =-3;
308 #define IS_SELECTED(s) (s!=DELETED && s!=NOT_DONE && s!=REMOVED)
309 
310 /* -------------------------------------------------------------------------- */
311 /*
312    smoothAggs - greedy grab of with G1 (unsquared graph) -- AIJ specific
313      - AGG-MG specific: clears singletons out of 'selected_2'
314 
315    Input Parameter:
316    . Gmat_2 - glabal matrix of graph (data not defined)
317    . Gmat_1 - base graph to grab with
318    Input/Output Parameter:
319    . aggs_2 - linked list of aggs with gids)
320 */
321 #undef __FUNCT__
322 #define __FUNCT__ "smoothAggs"
323 static PetscErrorCode smoothAggs(const Mat Gmat_2, /* base (squared) graph */
324                                  const Mat Gmat_1,  /* base graph */
325                                  /* const IS selected_2, [nselected local] selected vertices */
326                                  PetscCoarsenData *aggs_2)  /* [nselected local] global ID of aggregate */
327 {
328   PetscErrorCode ierr;
329   PetscBool      isMPI;
330   Mat_SeqAIJ     *matA_1, *matB_1=0, *matA_2, *matB_2=0;
331   MPI_Comm       comm;
332   PetscMPIInt    rank,size;
333   PetscInt       lid,*ii,*idx,ix,Iend,my0,kk,n,j;
334   Mat_MPIAIJ     *mpimat_2 = 0, *mpimat_1=0;
335   const PetscInt nloc      = Gmat_2->rmap->n;
336   PetscScalar    *cpcol_1_state,*cpcol_2_state,*cpcol_2_par_orig,*lid_parent_gid;
337   PetscInt       *lid_cprowID_1;
338   NState         *lid_state;
339   Vec            ghost_par_orig2;
340 
341   PetscFunctionBegin;
342   ierr = PetscObjectGetComm((PetscObject)Gmat_2,&comm);CHKERRQ(ierr);
343   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
344   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
345   ierr = MatGetOwnershipRange(Gmat_1,&my0,&Iend);CHKERRQ(ierr);
346 
347   if (PETSC_FALSE) {
348     PetscViewer viewer; char fname[32]; static int llev=0;
349     sprintf(fname,"Gmat2_%d.m",llev++);
350     PetscViewerASCIIOpen(comm,fname,&viewer);
351     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
352     ierr = MatView(Gmat_2, viewer);CHKERRQ(ierr);
353     ierr = PetscViewerDestroy(&viewer);
354   }
355 
356   /* get submatrices */
357   ierr = PetscObjectTypeCompare((PetscObject)Gmat_1, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
358   if (isMPI) {
359     /* grab matrix objects */
360     mpimat_2 = (Mat_MPIAIJ*)Gmat_2->data;
361     mpimat_1 = (Mat_MPIAIJ*)Gmat_1->data;
362     matA_1   = (Mat_SeqAIJ*)mpimat_1->A->data;
363     matB_1   = (Mat_SeqAIJ*)mpimat_1->B->data;
364     matA_2   = (Mat_SeqAIJ*)mpimat_2->A->data;
365     matB_2   = (Mat_SeqAIJ*)mpimat_2->B->data;
366 
367     /* force compressed row storage for B matrix in AuxMat */
368     matB_1->compressedrow.check = PETSC_TRUE;
369 
370     ierr = MatCheckCompressedRow(mpimat_1->B,&matB_1->compressedrow,matB_1->i,Gmat_1->rmap->n,-1.0);CHKERRQ(ierr);
371 
372     ierr = PetscMalloc(nloc*sizeof(PetscInt), &lid_cprowID_1);CHKERRQ(ierr);
373     for (lid = 0; lid < nloc; lid++) lid_cprowID_1[lid] = -1;
374     for (ix=0; ix<matB_1->compressedrow.nrows; ix++) {
375       PetscInt lid = matB_1->compressedrow.rindex[ix];
376       lid_cprowID_1[lid] = ix;
377     }
378   } else {
379     matA_1        = (Mat_SeqAIJ*)Gmat_1->data;
380     matA_2        = (Mat_SeqAIJ*)Gmat_2->data;
381     lid_cprowID_1 = NULL;
382   }
383   if (!(matA_1 && !matA_1->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matA_1 && !matA_1->compressedrow.use)");
384   if (!(matB_1==0 || matB_1->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matB_1==0 || matB_1->compressedrow.use)");
385   if (!(matA_2 && !matA_2->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matA_2 && !matA_2->compressedrow.use)");
386   if (!(matB_2==0 || matB_2->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matB_2==0 || matB_2->compressedrow.use)");
387 
388   /* get state of locals and selected gid for deleted */
389   ierr = PetscMalloc(nloc*sizeof(NState), &lid_state);CHKERRQ(ierr);
390   ierr = PetscMalloc(nloc*sizeof(PetscScalar), &lid_parent_gid);CHKERRQ(ierr);
391   for (lid = 0; lid < nloc; lid++) {
392     lid_parent_gid[lid] = -1.0;
393     lid_state[lid]      = DELETED;
394   }
395 
396   /* set lid_state */
397   for (lid = 0; lid < nloc; lid++) {
398     PetscCDPos pos;
399     ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
400     if (pos) {
401       PetscInt gid1;
402 
403       ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
404       if (gid1 != lid+my0) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"gid1 %D != lid %D + my0 %D",gid1,lid,my0);
405       lid_state[lid] = gid1;
406     }
407   }
408 
409   /* map local to selected local, DELETED means a ghost owns it */
410   for (lid=kk=0; lid<nloc; lid++) {
411     NState state = lid_state[lid];
412     if (IS_SELECTED(state)) {
413       PetscCDPos pos;
414       ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
415       while (pos) {
416         PetscInt gid1;
417         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
418         ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
419 
420         if (gid1 >= my0 && gid1 < Iend) lid_parent_gid[gid1-my0] = (PetscScalar)(lid + my0);
421       }
422     }
423   }
424   /* get 'cpcol_1/2_state' & cpcol_2_par_orig - uses mpimat_1/2->lvec for temp space */
425   if (isMPI) {
426     Vec tempVec;
427     /* get 'cpcol_1_state' */
428     ierr = MatGetVecs(Gmat_1, &tempVec, 0);CHKERRQ(ierr);
429     for (kk=0,j=my0; kk<nloc; kk++,j++) {
430       PetscScalar v = (PetscScalar)lid_state[kk];
431       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
432     }
433     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
434     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
435     ierr = VecScatterBegin(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
436     ierr =   VecScatterEnd(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
437     ierr = VecGetArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
438     /* get 'cpcol_2_state' */
439     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
440     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
441     ierr = VecGetArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
442     /* get 'cpcol_2_par_orig' */
443     for (kk=0,j=my0; kk<nloc; kk++,j++) {
444       PetscScalar v = (PetscScalar)lid_parent_gid[kk];
445       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
446     }
447     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
448     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
449     ierr = VecDuplicate(mpimat_2->lvec, &ghost_par_orig2);CHKERRQ(ierr);
450     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
451     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
452     ierr = VecGetArray(ghost_par_orig2, &cpcol_2_par_orig);CHKERRQ(ierr);
453 
454     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
455   } /* ismpi */
456 
457   /* doit */
458   for (lid=0; lid<nloc; lid++) {
459     NState state = lid_state[lid];
460     if (IS_SELECTED(state)) {
461       /* steal locals */
462       ii  = matA_1->i; n = ii[lid+1] - ii[lid];
463       idx = matA_1->j + ii[lid];
464       for (j=0; j<n; j++) {
465         PetscInt lidj   = idx[j], sgid;
466         NState   statej = lid_state[lidj];
467         if (statej==DELETED && (sgid=(PetscInt)PetscRealPart(lid_parent_gid[lidj])) != lid+my0) { /* steal local */
468           lid_parent_gid[lidj] = (PetscScalar)(lid+my0); /* send this if sgid is not local */
469           if (sgid >= my0 && sgid < Iend) {       /* I'm stealing this local from a local sgid */
470             PetscInt   hav=0,slid=sgid-my0,gidj=lidj+my0;
471             PetscCDPos pos,last=NULL;
472             /* looking for local from local so id_llist_2 works */
473             ierr = PetscCDGetHeadPos(aggs_2,slid,&pos);CHKERRQ(ierr);
474             while (pos) {
475               PetscInt gid;
476               ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
477               if (gid == gidj) {
478                 if (!last) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"last cannot be null");
479                 ierr = PetscCDRemoveNextNode(aggs_2, slid, last);CHKERRQ(ierr);
480                 ierr = PetscCDAppendNode(aggs_2, lid, pos);CHKERRQ(ierr);
481                 hav  = 1;
482                 break;
483               } else last = pos;
484 
485               ierr = PetscCDGetNextPos(aggs_2,slid,&pos);CHKERRQ(ierr);
486             }
487             if (hav!=1) {
488               if (!hav) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
489               SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
490             }
491           } else {            /* I'm stealing this local, owned by a ghost */
492             if (sgid != -1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Have un-symmetric graph (apparently). Use '-pc_gamg_sym_graph true' to symetrize the graph or '-pc_gamg_threshold 0.0' if the matrix is structurally symmetric.");
493             ierr = PetscCDAppendID(aggs_2, lid, lidj+my0);CHKERRQ(ierr);
494           }
495         }
496       } /* local neighbors */
497     } else if (state == DELETED && lid_cprowID_1) {
498       PetscInt sgidold = (PetscInt)PetscRealPart(lid_parent_gid[lid]);
499       /* see if I have a selected ghost neighbor that will steal me */
500       if ((ix=lid_cprowID_1[lid]) != -1) {
501         ii  = matB_1->compressedrow.i; n = ii[ix+1] - ii[ix];
502         idx = matB_1->j + ii[ix];
503         for (j=0; j<n; j++) {
504           PetscInt cpid   = idx[j];
505           NState   statej = (NState)PetscRealPart(cpcol_1_state[cpid]);
506           if (IS_SELECTED(statej) && sgidold != (PetscInt)statej) { /* ghost will steal this, remove from my list */
507             lid_parent_gid[lid] = (PetscScalar)statej; /* send who selected */
508             if (sgidold>=my0 && sgidold<Iend) { /* this was mine */
509               PetscInt   hav=0,oldslidj=sgidold-my0;
510               PetscCDPos pos,last=NULL;
511               /* remove from 'oldslidj' list */
512               ierr = PetscCDGetHeadPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
513               while (pos) {
514                 PetscInt gid;
515                 ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
516                 if (lid+my0 == gid) {
517                   /* id_llist_2[lastid] = id_llist_2[flid];   /\* remove lid from oldslidj list *\/ */
518                   if (!last) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"last cannot be null");
519                   ierr = PetscCDRemoveNextNode(aggs_2, oldslidj, last);CHKERRQ(ierr);
520                   /* ghost (PetscScalar)statej will add this later */
521                   hav = 1;
522                   break;
523                 } else last = pos;
524 
525                 ierr = PetscCDGetNextPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
526               }
527               if (hav!=1) {
528                 if (hav==0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
529                 SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
530               }
531             } else {
532               /* ghosts remove this later */
533             }
534           }
535         }
536       }
537     } /* selected/deleted */
538   } /* node loop */
539 
540   if (isMPI) {
541     PetscScalar   *cpcol_2_parent,*cpcol_2_gid;
542     Vec           tempVec,ghostgids2,ghostparents2;
543     PetscInt      cpid,nghost_2;
544     GAMGHashTable gid_cpid;
545 
546     ierr = VecGetSize(mpimat_2->lvec, &nghost_2);CHKERRQ(ierr);
547     ierr = MatGetVecs(Gmat_2, &tempVec, 0);CHKERRQ(ierr);
548 
549     /* get 'cpcol_2_parent' */
550     for (kk=0,j=my0; kk<nloc; kk++,j++) {
551       ierr = VecSetValues(tempVec, 1, &j, &lid_parent_gid[kk], INSERT_VALUES);CHKERRQ(ierr);
552     }
553     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
554     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
555     ierr = VecDuplicate(mpimat_2->lvec, &ghostparents2);CHKERRQ(ierr);
556     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
557     ierr = VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
558     ierr = VecGetArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
559 
560     /* get 'cpcol_2_gid' */
561     for (kk=0,j=my0; kk<nloc; kk++,j++) {
562       PetscScalar v = (PetscScalar)j;
563       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
564     }
565     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
566     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
567     ierr = VecDuplicate(mpimat_2->lvec, &ghostgids2);CHKERRQ(ierr);
568     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
569     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
570     ierr = VecGetArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
571 
572     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
573 
574     /* look for deleted ghosts and add to table */
575     ierr = GAMGTableCreate(2*nghost_2+1, &gid_cpid);CHKERRQ(ierr);
576     for (cpid = 0; cpid < nghost_2; cpid++) {
577       NState state = (NState)PetscRealPart(cpcol_2_state[cpid]);
578       if (state==DELETED) {
579         PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
580         PetscInt sgid_old = (PetscInt)PetscRealPart(cpcol_2_par_orig[cpid]);
581         if (sgid_old == -1 && sgid_new != -1) {
582           PetscInt gid = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
583           ierr = GAMGTableAdd(&gid_cpid, gid, cpid);CHKERRQ(ierr);
584         }
585       }
586     }
587 
588     /* look for deleted ghosts and see if they moved - remove it */
589     for (lid=0; lid<nloc; lid++) {
590       NState state = lid_state[lid];
591       if (IS_SELECTED(state)) {
592         PetscCDPos pos,last=NULL;
593         /* look for deleted ghosts and see if they moved */
594         ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
595         while (pos) {
596           PetscInt gid;
597           ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
598 
599           if (gid < my0 || gid >= Iend) {
600             ierr = GAMGTableFind(&gid_cpid, gid, &cpid);CHKERRQ(ierr);
601             if (cpid != -1) {
602               /* a moved ghost - */
603               /* id_llist_2[lastid] = id_llist_2[flid];    /\* remove 'flid' from list *\/ */
604               ierr = PetscCDRemoveNextNode(aggs_2, lid, last);CHKERRQ(ierr);
605             } else last = pos;
606           } else last = pos;
607 
608           ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
609         } /* loop over list of deleted */
610       } /* selected */
611     }
612     ierr = GAMGTableDestroy(&gid_cpid);CHKERRQ(ierr);
613 
614     /* look at ghosts, see if they changed - and it */
615     for (cpid = 0; cpid < nghost_2; cpid++) {
616       PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
617       if (sgid_new >= my0 && sgid_new < Iend) { /* this is mine */
618         PetscInt   gid     = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
619         PetscInt   slid_new=sgid_new-my0,hav=0;
620         PetscCDPos pos;
621         /* search for this gid to see if I have it */
622         ierr = PetscCDGetHeadPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
623         while (pos) {
624           PetscInt gidj;
625           ierr = PetscLLNGetID(pos, &gidj);CHKERRQ(ierr);
626           ierr = PetscCDGetNextPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
627 
628           if (gidj == gid) { hav = 1; break; }
629         }
630         if (hav != 1) {
631           /* insert 'flidj' into head of llist */
632           ierr = PetscCDAppendID(aggs_2, slid_new, gid);CHKERRQ(ierr);
633         }
634       }
635     }
636 
637     ierr = VecRestoreArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
638     ierr = VecRestoreArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
639     ierr = VecRestoreArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
640     ierr = VecRestoreArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
641     ierr = PetscFree(lid_cprowID_1);CHKERRQ(ierr);
642     ierr = VecDestroy(&ghostgids2);CHKERRQ(ierr);
643     ierr = VecDestroy(&ghostparents2);CHKERRQ(ierr);
644     ierr = VecDestroy(&ghost_par_orig2);CHKERRQ(ierr);
645   }
646 
647   ierr = PetscFree(lid_parent_gid);CHKERRQ(ierr);
648   ierr = PetscFree(lid_state);CHKERRQ(ierr);
649   PetscFunctionReturn(0);
650 }
651 
652 /* -------------------------------------------------------------------------- */
653 /*
654    PCSetData_AGG - called if data is not set with PCSetCoordinates.
655       Looks in Mat for near null space.
656       Does not work for Stokes
657 
658   Input Parameter:
659    . pc -
660    . a_A - matrix to get (near) null space out of.
661 */
662 #undef __FUNCT__
663 #define __FUNCT__ "PCSetData_AGG"
664 PetscErrorCode PCSetData_AGG(PC pc, Mat a_A)
665 {
666   PetscErrorCode ierr;
667   PC_MG          *mg      = (PC_MG*)pc->data;
668   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
669   MatNullSpace   mnull;
670 
671   PetscFunctionBegin;
672   ierr = MatGetNearNullSpace(a_A, &mnull);CHKERRQ(ierr);
673   if (!mnull) {
674     PetscInt bs,NN,MM;
675     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr);
676     ierr = MatGetLocalSize(a_A, &MM, &NN);CHKERRQ(ierr);
677     if (MM % bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MM %D must be divisible by bs %D",MM,bs);
678     ierr = PCSetCoordinates_AGG(pc, bs, MM/bs, NULL);CHKERRQ(ierr);
679   } else {
680     PetscReal *nullvec;
681     PetscBool has_const;
682     PetscInt  i,j,mlocal,nvec,bs;
683     const Vec *vecs; const PetscScalar *v;
684     ierr = MatGetLocalSize(a_A,&mlocal,NULL);CHKERRQ(ierr);
685     ierr = MatNullSpaceGetVecs(mnull, &has_const, &nvec, &vecs);CHKERRQ(ierr);
686     ierr = PetscMalloc((nvec+!!has_const)*mlocal*sizeof(*nullvec),&nullvec);CHKERRQ(ierr);
687     if (has_const) for (i=0; i<mlocal; i++) nullvec[i] = 1.0;
688     for (i=0; i<nvec; i++) {
689       ierr = VecGetArrayRead(vecs[i],&v);CHKERRQ(ierr);
690       for (j=0; j<mlocal; j++) nullvec[(i+!!has_const)*mlocal + j] = PetscRealPart(v[j]);
691       ierr = VecRestoreArrayRead(vecs[i],&v);CHKERRQ(ierr);
692     }
693     pc_gamg->data           = nullvec;
694     pc_gamg->data_cell_cols = (nvec+!!has_const);
695 
696     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr); /* this does not work for Stokes */
697 
698     pc_gamg->data_cell_rows = bs;
699   }
700   PetscFunctionReturn(0);
701 }
702 
703 /* -------------------------------------------------------------------------- */
704 /*
705  formProl0
706 
707    Input Parameter:
708    . agg_llists - list of arrays with aggregates
709    . bs - block size
710    . nSAvec - column bs of new P
711    . my0crs - global index of start of locals
712    . data_stride - bs*(nloc nodes + ghost nodes)
713    . data_in[data_stride*nSAvec] - local data on fine grid
714    . flid_fgid[data_stride/bs] - make local to global IDs, includes ghosts in 'locals_llist'
715   Output Parameter:
716    . a_data_out - in with fine grid data (w/ghosts), out with coarse grid data
717    . a_Prol - prolongation operator
718 */
719 #undef __FUNCT__
720 #define __FUNCT__ "formProl0"
721 static PetscErrorCode formProl0(const PetscCoarsenData *agg_llists, /* list from selected vertices of aggregate unselected vertices */
722                                 const PetscInt bs,          /* (row) block size */
723                                 const PetscInt nSAvec,      /* column bs */
724                                 const PetscInt my0crs,      /* global index of start of locals */
725                                 const PetscInt data_stride, /* (nloc+nghost)*bs */
726                                 PetscReal      data_in[],   /* [data_stride][nSAvec] */
727                                 const PetscInt flid_fgid[], /* [data_stride/bs] */
728                                 PetscReal **a_data_out,
729                                 Mat a_Prol) /* prolongation operator (output)*/
730 {
731   PetscErrorCode ierr;
732   PetscInt       Istart,my0,Iend,nloc,clid,flid,aggID,kk,jj,ii,mm,ndone,nSelected,minsz,nghosts,out_data_stride;
733   MPI_Comm       comm;
734   PetscMPIInt    rank, size;
735   PetscReal      *out_data;
736   PetscCDPos     pos;
737   GAMGHashTable  fgid_flid;
738 
739 /* #define OUT_AGGS */
740 #if defined(OUT_AGGS)
741   static PetscInt llev = 0; char fname[32]; FILE *file = NULL; PetscInt pM;
742 #endif
743 
744   PetscFunctionBegin;
745   ierr = PetscObjectGetComm((PetscObject)a_Prol,&comm);CHKERRQ(ierr);
746   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
747   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
748   ierr = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
749   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
750   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Iend %D - Istart %d must be divisible by bs %D",Iend,Istart,bs);
751   Iend   /= bs;
752   nghosts = data_stride/bs - nloc;
753 
754   ierr = GAMGTableCreate(2*nghosts+1, &fgid_flid);CHKERRQ(ierr);
755   for (kk=0; kk<nghosts; kk++) {
756     ierr = GAMGTableAdd(&fgid_flid, flid_fgid[nloc+kk], nloc+kk);CHKERRQ(ierr);
757   }
758 
759 #if defined(OUT_AGGS)
760   sprintf(fname,"aggs_%d_%d.m",llev++,rank);
761   if (llev==1) file = fopen(fname,"w");
762   MatGetSize(a_Prol, &pM, &jj);
763 #endif
764 
765   /* count selected -- same as number of cols of P */
766   for (nSelected=mm=0; mm<nloc; mm++) {
767     PetscBool ise;
768     ierr = PetscCDEmptyAt(agg_llists, mm, &ise);CHKERRQ(ierr);
769     if (!ise) nSelected++;
770   }
771   ierr = MatGetOwnershipRangeColumn(a_Prol, &ii, &jj);CHKERRQ(ierr);
772   if ((ii/nSAvec) != my0crs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D /nSAvec %D  != my0crs %D",ii,nSAvec,my0crs);
773   if (nSelected != (jj-ii)/nSAvec) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nSelected %D != (jj %D - ii %D)/nSAvec %D",nSelected,jj,ii,nSAvec);
774 
775   /* aloc space for coarse point data (output) */
776   out_data_stride = nSelected*nSAvec;
777 
778   ierr = PetscMalloc(out_data_stride*nSAvec*sizeof(PetscReal), &out_data);CHKERRQ(ierr);
779   for (ii=0;ii<out_data_stride*nSAvec;ii++) out_data[ii]=1.e300;
780   *a_data_out = out_data; /* output - stride nSelected*nSAvec */
781 
782   /* find points and set prolongation */
783   minsz = 100;
784   ndone = 0;
785   for (mm = clid = 0; mm < nloc; mm++) {
786     ierr = PetscCDSizeAt(agg_llists, mm, &jj);CHKERRQ(ierr);
787     if (jj > 0) {
788       const PetscInt lid = mm, cgid = my0crs + clid;
789       PetscInt       cids[100]; /* max bs */
790       PetscBLASInt   asz  =jj,M=asz*bs,N=nSAvec,INFO;
791       PetscBLASInt   Mdata=M+((N-M>0) ? N-M : 0),LDA=Mdata,LWORK=N*bs;
792       PetscScalar    *qqc,*qqr,*TAU,*WORK;
793       PetscInt       *fids;
794       PetscReal      *data;
795       /* count agg */
796       if (asz<minsz) minsz = asz;
797 
798       /* get block */
799       ierr = PetscMalloc((Mdata*N)*sizeof(PetscScalar), &qqc);CHKERRQ(ierr);
800       ierr = PetscMalloc((M*N)*sizeof(PetscScalar), &qqr);CHKERRQ(ierr);
801       ierr = PetscMalloc(N*sizeof(PetscScalar), &TAU);CHKERRQ(ierr);
802       ierr = PetscMalloc(LWORK*sizeof(PetscScalar), &WORK);CHKERRQ(ierr);
803       ierr = PetscMalloc(M*sizeof(PetscInt), &fids);CHKERRQ(ierr);
804 
805       aggID = 0;
806       ierr  = PetscCDGetHeadPos(agg_llists,lid,&pos);CHKERRQ(ierr);
807       while (pos) {
808         PetscInt gid1;
809         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
810         ierr = PetscCDGetNextPos(agg_llists,lid,&pos);CHKERRQ(ierr);
811 
812         if (gid1 >= my0 && gid1 < Iend) flid = gid1 - my0;
813         else {
814           ierr = GAMGTableFind(&fgid_flid, gid1, &flid);CHKERRQ(ierr);
815           if (flid < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot find gid1 in table");
816         }
817         /* copy in B_i matrix - column oriented */
818         data = &data_in[flid*bs];
819         for (kk = ii = 0; ii < bs; ii++) {
820           for (jj = 0; jj < N; jj++) {
821             PetscReal d = data[jj*data_stride + ii];
822             qqc[jj*Mdata + aggID*bs + ii] = d;
823           }
824         }
825 #if defined(OUT_AGGS)
826         if (llev==1) {
827           char     str[] = "plot(%e,%e,'r*'), hold on,\n", col[] = "rgbkmc", sim[] = "*os+h>d<vx^";
828           PetscInt MM,pi,pj;
829           str[12] = col[(clid+17*rank)%6]; str[13] = sim[(clid+17*rank)%11];
830           MM      = (PetscInt)(PetscSqrtReal((PetscReal)pM));
831           pj      = gid1/MM; pi = gid1%MM;
832           fprintf(file,str,(double)pi,(double)pj);
833           /* fprintf(file,str,data[2*data_stride+1],-data[2*data_stride]); */
834         }
835 #endif
836         /* set fine IDs */
837         for (kk=0; kk<bs; kk++) fids[aggID*bs + kk] = flid_fgid[flid]*bs + kk;
838 
839         aggID++;
840       }
841 
842       /* pad with zeros */
843       for (ii = asz*bs; ii < Mdata; ii++) {
844         for (jj = 0; jj < N; jj++, kk++) {
845           qqc[jj*Mdata + ii] = .0;
846         }
847       }
848 
849       ndone += aggID;
850       /* QR */
851       ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
852       PetscStackCall("LAPACKgeqrf",LAPACKgeqrf_(&Mdata, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO));
853       ierr = PetscFPTrapPop();CHKERRQ(ierr);
854       if (INFO != 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xGEQRF error");
855       /* get R - column oriented - output B_{i+1} */
856       {
857         PetscReal *data = &out_data[clid*nSAvec];
858         for (jj = 0; jj < nSAvec; jj++) {
859           for (ii = 0; ii < nSAvec; ii++) {
860            if (data[jj*out_data_stride + ii] != 1.e300) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"data[jj*out_data_stride + ii] != 1.e300");
861            if (ii <= jj) data[jj*out_data_stride + ii] = PetscRealPart(qqc[jj*Mdata + ii]);
862            else data[jj*out_data_stride + ii] = 0.;
863           }
864         }
865       }
866 
867       /* get Q - row oriented */
868       PetscStackCall("LAPACKungqr",LAPACKungqr_(&Mdata, &N, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO));
869       if (INFO != 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xORGQR error arg %d",-INFO);
870 
871       for (ii = 0; ii < M; ii++) {
872         for (jj = 0; jj < N; jj++) {
873           qqr[N*ii + jj] = qqc[jj*Mdata + ii];
874         }
875       }
876 
877       /* add diagonal block of P0 */
878       for (kk=0; kk<N; kk++) {
879         cids[kk] = N*cgid + kk; /* global col IDs in P0 */
880       }
881       ierr = MatSetValues(a_Prol,M,fids,N,cids,qqr,INSERT_VALUES);CHKERRQ(ierr);
882 
883       ierr = PetscFree(qqc);CHKERRQ(ierr);
884       ierr = PetscFree(qqr);CHKERRQ(ierr);
885       ierr = PetscFree(TAU);CHKERRQ(ierr);
886       ierr = PetscFree(WORK);CHKERRQ(ierr);
887       ierr = PetscFree(fids);CHKERRQ(ierr);
888       clid++;
889     } /* coarse agg */
890   } /* for all fine nodes */
891   ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
892   ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
893 
894 /* ierr = MPI_Allreduce(&ndone, &ii, 1, MPIU_INT, MPIU_SUM, comm); */
895 /* MatGetSize(a_Prol, &kk, &jj); */
896 /* ierr = MPI_Allreduce(&minsz, &jj, 1, MPIU_INT, MPIU_MIN, comm); */
897 /* PetscPrintf(comm," **** [%d]%s %d total done, %d nodes (%d local done), min agg. size = %d\n",rank,__FUNCT__,ii,kk/bs,ndone,jj); */
898 
899 #if defined(OUT_AGGS)
900   if (llev==1) fclose(file);
901 #endif
902   ierr = GAMGTableDestroy(&fgid_flid);CHKERRQ(ierr);
903   PetscFunctionReturn(0);
904 }
905 
906 /* -------------------------------------------------------------------------- */
907 /*
908    PCGAMGgraph_AGG
909 
910   Input Parameter:
911    . pc - this
912    . Amat - matrix on this fine level
913   Output Parameter:
914    . a_Gmat -
915 */
916 #undef __FUNCT__
917 #define __FUNCT__ "PCGAMGgraph_AGG"
918 PetscErrorCode PCGAMGgraph_AGG(PC pc,const Mat Amat,Mat *a_Gmat)
919 {
920   PetscErrorCode            ierr;
921   PC_MG                     *mg          = (PC_MG*)pc->data;
922   PC_GAMG                   *pc_gamg     = (PC_GAMG*)mg->innerctx;
923   const PetscInt            verbose      = pc_gamg->verbose;
924   const PetscReal           vfilter      = pc_gamg->threshold;
925   PC_GAMG_AGG               *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
926   PetscMPIInt               rank,size;
927   Mat                       Gmat;
928   MPI_Comm                  comm;
929   PetscBool /* set,flg , */ symm;
930 
931   PetscFunctionBegin;
932   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
933 #if defined PETSC_USE_LOG
934   ierr = PetscLogEventBegin(PC_GAMGGgraph_AGG,0,0,0,0);CHKERRQ(ierr);
935 #endif
936   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
937   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
938 
939   /* ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr); || !(set && flg) -- this causes lot of symm calls */
940   symm = (PetscBool)(pc_gamg_agg->sym_graph); /* && !pc_gamg_agg->square_graph; */
941 
942   ierr = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
943   ierr = PCGAMGFilterGraph(&Gmat, vfilter, symm, verbose);CHKERRQ(ierr);
944 
945   *a_Gmat = Gmat;
946 
947 #if defined PETSC_USE_LOG
948   ierr = PetscLogEventEnd(PC_GAMGGgraph_AGG,0,0,0,0);CHKERRQ(ierr);
949 #endif
950   PetscFunctionReturn(0);
951 }
952 
953 /* -------------------------------------------------------------------------- */
954 /*
955    PCGAMGCoarsen_AGG
956 
957   Input Parameter:
958    . a_pc - this
959   Input/Output Parameter:
960    . a_Gmat1 - graph on this fine level - coarsening can change this (squares it)
961   Output Parameter:
962    . agg_lists - list of aggregates
963 */
964 #undef __FUNCT__
965 #define __FUNCT__ "PCGAMGCoarsen_AGG"
966 PetscErrorCode PCGAMGCoarsen_AGG(PC a_pc,Mat *a_Gmat1,PetscCoarsenData **agg_lists)
967 {
968   PetscErrorCode ierr;
969   PC_MG          *mg          = (PC_MG*)a_pc->data;
970   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
971   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
972   Mat            mat,Gmat2, Gmat1 = *a_Gmat1;  /* squared graph */
973   const PetscInt verbose = pc_gamg->verbose;
974   IS             perm;
975   PetscInt       Ii,nloc,bs,n,m;
976   PetscInt       *permute;
977   PetscBool      *bIndexSet;
978   MatCoarsen     crs;
979   MPI_Comm       comm;
980   PetscMPIInt    rank,size;
981 
982   PetscFunctionBegin;
983 #if defined PETSC_USE_LOG
984   ierr = PetscLogEventBegin(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
985 #endif
986   ierr = PetscObjectGetComm((PetscObject)Gmat1,&comm);CHKERRQ(ierr);
987   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
988   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
989   ierr = MatGetLocalSize(Gmat1, &n, &m);CHKERRQ(ierr);
990   ierr = MatGetBlockSize(Gmat1, &bs);CHKERRQ(ierr);
991   if (bs != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"bs %D must be 1",bs);
992   nloc = n/bs;
993 
994   if (pc_gamg_agg->square_graph) {
995     if (verbose > 1) PetscPrintf(comm,"[%d]%s square graph\n",rank,__FUNCT__);
996     /* ierr = MatMatTransposeMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2); */
997     ierr = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
998     if (verbose > 2) {
999       ierr = PetscPrintf(comm,"[%d]%s square graph done\n",rank,__FUNCT__);CHKERRQ(ierr);
1000       /* check for symetry */
1001       if (verbose > 4) {
1002 
1003       }
1004     }
1005   } else Gmat2 = Gmat1;
1006 
1007   /* get MIS aggs */
1008   /* randomize */
1009   ierr = PetscMalloc(nloc*sizeof(PetscInt), &permute);CHKERRQ(ierr);
1010   ierr = PetscMalloc(nloc*sizeof(PetscBool), &bIndexSet);CHKERRQ(ierr);
1011   for (Ii = 0; Ii < nloc; Ii++) {
1012     bIndexSet[Ii] = PETSC_FALSE;
1013     permute[Ii]   = Ii;
1014   }
1015   srand(1); /* make deterministic */
1016   for (Ii = 0; Ii < nloc; Ii++) {
1017     PetscInt iSwapIndex = rand()%nloc;
1018     if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
1019       PetscInt iTemp = permute[iSwapIndex];
1020       permute[iSwapIndex]   = permute[Ii];
1021       permute[Ii]           = iTemp;
1022       bIndexSet[iSwapIndex] = PETSC_TRUE;
1023     }
1024   }
1025   ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
1026 
1027   if (verbose > 1) PetscPrintf(comm,"[%d]%s coarsen graph\n",rank,__FUNCT__);
1028 
1029   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_USE_POINTER, &perm);CHKERRQ(ierr);
1030 #if defined PETSC_GAMG_USE_LOG
1031   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
1032 #endif
1033   ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
1034   /* ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr); */
1035   ierr = MatCoarsenSetFromOptions(crs);CHKERRQ(ierr);
1036   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
1037   ierr = MatCoarsenSetAdjacency(crs, Gmat2);CHKERRQ(ierr);
1038   ierr = MatCoarsenSetVerbose(crs, pc_gamg->verbose);CHKERRQ(ierr);
1039   ierr = MatCoarsenSetStrictAggs(crs, PETSC_TRUE);CHKERRQ(ierr);
1040   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
1041   ierr = MatCoarsenGetData(crs, agg_lists);CHKERRQ(ierr); /* output */
1042   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
1043 
1044   ierr = ISDestroy(&perm);CHKERRQ(ierr);
1045   ierr = PetscFree(permute);CHKERRQ(ierr);
1046 #if defined PETSC_GAMG_USE_LOG
1047   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
1048 #endif
1049   if (verbose > 2) PetscPrintf(comm,"[%d]%s coarsen graph done\n",rank,__FUNCT__);
1050 
1051   /* smooth aggs */
1052   if (Gmat2 != Gmat1) {
1053     const PetscCoarsenData *llist = *agg_lists;
1054     ierr     = smoothAggs(Gmat2, Gmat1, *agg_lists);CHKERRQ(ierr);
1055     ierr     = MatDestroy(&Gmat1);CHKERRQ(ierr);
1056     *a_Gmat1 = Gmat2; /* output */
1057     ierr     = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1058     if (mat) SETERRQ(comm,PETSC_ERR_ARG_WRONG, "Auxilary matrix with squared graph????");
1059   } else {
1060     const PetscCoarsenData *llist = *agg_lists;
1061     /* see if we have a matrix that takes precedence (returned from MatCoarsenAppply) */
1062     ierr = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1063     if (mat) {
1064       ierr     = MatDestroy(&Gmat1);CHKERRQ(ierr);
1065       *a_Gmat1 = mat; /* output */
1066     }
1067   }
1068 #if defined PETSC_USE_LOG
1069   ierr = PetscLogEventEnd(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
1070 #endif
1071   if (verbose > 2) PetscPrintf(comm,"[%d]%s PCGAMGCoarsen_AGG done\n",rank,__FUNCT__);
1072   PetscFunctionReturn(0);
1073 }
1074 
1075 /* -------------------------------------------------------------------------- */
1076 /*
1077  PCGAMGProlongator_AGG
1078 
1079  Input Parameter:
1080  . pc - this
1081  . Amat - matrix on this fine level
1082  . Graph - used to get ghost data for nodes in
1083  . agg_lists - list of aggregates
1084  Output Parameter:
1085  . a_P_out - prolongation operator to the next level
1086  */
1087 #undef __FUNCT__
1088 #define __FUNCT__ "PCGAMGProlongator_AGG"
1089 PetscErrorCode PCGAMGProlongator_AGG(PC pc,const Mat Amat,const Mat Gmat,PetscCoarsenData *agg_lists,Mat *a_P_out)
1090 {
1091   PC_MG          *mg       = (PC_MG*)pc->data;
1092   PC_GAMG        *pc_gamg  = (PC_GAMG*)mg->innerctx;
1093   const PetscInt verbose   = pc_gamg->verbose;
1094   const PetscInt data_cols = pc_gamg->data_cell_cols;
1095   PetscErrorCode ierr;
1096   PetscInt       Istart,Iend,nloc,ii,jj,kk,my0,nLocalSelected,bs;
1097   Mat            Prol;
1098   PetscMPIInt    rank, size;
1099   MPI_Comm       comm;
1100   const PetscInt col_bs = data_cols;
1101   PetscReal      *data_w_ghost;
1102   PetscInt       myCrs0, nbnodes=0, *flid_fgid;
1103 
1104   PetscFunctionBegin;
1105   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1106 #if defined PETSC_USE_LOG
1107   ierr = PetscLogEventBegin(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1108 #endif
1109   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1110   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1111   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1112   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
1113   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
1114   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(Iend %D - Istart %D) not divisible by bs %D",Iend,Istart,bs);
1115 
1116   /* get 'nLocalSelected' */
1117   for (ii=0, nLocalSelected = 0; ii < nloc; ii++) {
1118     PetscBool ise;
1119     /* filter out singletons 0 or 1? */
1120     ierr = PetscCDEmptyAt(agg_lists, ii, &ise);CHKERRQ(ierr);
1121     if (!ise) nLocalSelected++;
1122   }
1123 
1124   /* create prolongator, create P matrix */
1125   ierr = MatCreate(comm, &Prol);CHKERRQ(ierr);
1126   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*col_bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
1127   ierr = MatSetBlockSizes(Prol, bs, col_bs);CHKERRQ(ierr);
1128   ierr = MatSetType(Prol, MATAIJ);CHKERRQ(ierr);
1129   ierr = MatSeqAIJSetPreallocation(Prol, data_cols, NULL);CHKERRQ(ierr);
1130   ierr = MatMPIAIJSetPreallocation(Prol,data_cols, NULL,data_cols, NULL);CHKERRQ(ierr);
1131   /* nloc*bs, nLocalSelected*col_bs, */
1132   /* PETSC_DETERMINE, PETSC_DETERMINE, */
1133   /* data_cols, NULL, data_cols, NULL, */
1134   /* &Prol); */
1135 
1136   /* can get all points "removed" */
1137   ierr =  MatGetSize(Prol, &kk, &ii);CHKERRQ(ierr);
1138   if (ii==0) {
1139     if (verbose > 0) PetscPrintf(comm,"[%d]%s no selected points on coarse grid\n",rank,__FUNCT__);
1140     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
1141     *a_P_out = NULL;  /* out */
1142     PetscFunctionReturn(0);
1143   }
1144   if (verbose > 0) PetscPrintf(comm,"\t\t[%d]%s New grid %d nodes\n",rank,__FUNCT__,ii/col_bs);
1145   ierr = MatGetOwnershipRangeColumn(Prol, &myCrs0, &kk);CHKERRQ(ierr);
1146 
1147   if ((kk-myCrs0) % col_bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(kk %D -myCrs0 %D) not divisible by col_bs %D",kk,myCrs0,col_bs);
1148   myCrs0 = myCrs0/col_bs;
1149   if ((kk/col_bs-myCrs0) != nLocalSelected) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(kk %D/col_bs %D - myCrs0 %D) != nLocalSelected %D)",kk,col_bs,myCrs0,nLocalSelected);
1150 
1151   /* create global vector of data in 'data_w_ghost' */
1152 #if defined PETSC_GAMG_USE_LOG
1153   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1154 #endif
1155   if (size > 1) { /*  */
1156     PetscReal *tmp_gdata,*tmp_ldata,*tp2;
1157     ierr = PetscMalloc(nloc*sizeof(PetscReal), &tmp_ldata);CHKERRQ(ierr);
1158     for (jj = 0; jj < data_cols; jj++) {
1159       for (kk = 0; kk < bs; kk++) {
1160         PetscInt        ii,stride;
1161         const PetscReal *tp = pc_gamg->data + jj*bs*nloc + kk;
1162         for (ii = 0; ii < nloc; ii++, tp += bs) tmp_ldata[ii] = *tp;
1163 
1164         ierr = PCGAMGGetDataWithGhosts(Gmat, 1, tmp_ldata, &stride, &tmp_gdata);CHKERRQ(ierr);
1165 
1166         if (jj==0 && kk==0) { /* now I know how many todal nodes - allocate */
1167           ierr    = PetscMalloc(stride*bs*data_cols*sizeof(PetscReal), &data_w_ghost);CHKERRQ(ierr);
1168           nbnodes = bs*stride;
1169         }
1170         tp2 = data_w_ghost + jj*bs*stride + kk;
1171         for (ii = 0; ii < stride; ii++, tp2 += bs) *tp2 = tmp_gdata[ii];
1172         ierr = PetscFree(tmp_gdata);CHKERRQ(ierr);
1173       }
1174     }
1175     ierr = PetscFree(tmp_ldata);CHKERRQ(ierr);
1176   } else {
1177     nbnodes      = bs*nloc;
1178     data_w_ghost = (PetscReal*)pc_gamg->data;
1179   }
1180 
1181   /* get P0 */
1182   if (size > 1) {
1183     PetscReal *fid_glid_loc,*fiddata;
1184     PetscInt  stride;
1185 
1186     ierr = PetscMalloc(nloc*sizeof(PetscReal), &fid_glid_loc);CHKERRQ(ierr);
1187     for (kk=0; kk<nloc; kk++) fid_glid_loc[kk] = (PetscReal)(my0+kk);
1188     ierr = PCGAMGGetDataWithGhosts(Gmat, 1, fid_glid_loc, &stride, &fiddata);CHKERRQ(ierr);
1189     ierr = PetscMalloc(stride*sizeof(PetscInt), &flid_fgid);CHKERRQ(ierr);
1190     for (kk=0; kk<stride; kk++) flid_fgid[kk] = (PetscInt)fiddata[kk];
1191     ierr = PetscFree(fiddata);CHKERRQ(ierr);
1192 
1193     if (stride != nbnodes/bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"stride %D != nbnodes %D/bs %D",stride,nbnodes,bs);
1194     ierr = PetscFree(fid_glid_loc);CHKERRQ(ierr);
1195   } else {
1196     ierr = PetscMalloc(nloc*sizeof(PetscInt), &flid_fgid);CHKERRQ(ierr);
1197     for (kk=0; kk<nloc; kk++) flid_fgid[kk] = my0 + kk;
1198   }
1199 #if defined PETSC_GAMG_USE_LOG
1200   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1201   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1202 #endif
1203   {
1204     PetscReal *data_out = NULL;
1205     ierr = formProl0(agg_lists, bs, data_cols, myCrs0, nbnodes,data_w_ghost, flid_fgid, &data_out, Prol);CHKERRQ(ierr);
1206     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1207 
1208     pc_gamg->data           = data_out;
1209     pc_gamg->data_cell_rows = data_cols;
1210     pc_gamg->data_sz        = data_cols*data_cols*nLocalSelected;
1211   }
1212 #if defined PETSC_GAMG_USE_LOG
1213   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1214 #endif
1215   if (size > 1) ierr = PetscFree(data_w_ghost);CHKERRQ(ierr);
1216   ierr = PetscFree(flid_fgid);CHKERRQ(ierr);
1217 
1218   *a_P_out = Prol;  /* out */
1219 #if defined PETSC_USE_LOG
1220   ierr = PetscLogEventEnd(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1221 #endif
1222   PetscFunctionReturn(0);
1223 }
1224 
1225 /* -------------------------------------------------------------------------- */
1226 /*
1227    PCGAMGOptprol_AGG
1228 
1229   Input Parameter:
1230    . pc - this
1231    . Amat - matrix on this fine level
1232  In/Output Parameter:
1233    . a_P_out - prolongation operator to the next level
1234 */
1235 #undef __FUNCT__
1236 #define __FUNCT__ "PCGAMGOptprol_AGG"
1237 PetscErrorCode PCGAMGOptprol_AGG(PC pc,const Mat Amat,Mat *a_P)
1238 {
1239   PetscErrorCode ierr;
1240   PC_MG          *mg          = (PC_MG*)pc->data;
1241   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
1242   const PetscInt verbose      = pc_gamg->verbose;
1243   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
1244   PetscInt       jj;
1245   PetscMPIInt    rank,size;
1246   Mat            Prol  = *a_P;
1247   MPI_Comm       comm;
1248 
1249   PetscFunctionBegin;
1250   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1251 #if defined PETSC_USE_LOG
1252   ierr = PetscLogEventBegin(PC_GAMGOptprol_AGG,0,0,0,0);CHKERRQ(ierr);
1253 #endif
1254   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1255   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1256 
1257   /* smooth P0 */
1258   for (jj = 0; jj < pc_gamg_agg->nsmooths; jj++) {
1259     Mat       tMat;
1260     Vec       diag;
1261     PetscReal alpha, emax, emin;
1262 #if defined PETSC_GAMG_USE_LOG
1263     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1264 #endif
1265     if (jj == 0) {
1266       KSP eksp;
1267       Vec bb, xx;
1268       PC  epc;
1269       ierr = MatGetVecs(Amat, &bb, 0);CHKERRQ(ierr);
1270       ierr = MatGetVecs(Amat, &xx, 0);CHKERRQ(ierr);
1271       {
1272         PetscRandom rctx;
1273         ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
1274         ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
1275         ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
1276         ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
1277       }
1278 
1279       /* zeroing out BC rows -- needed for crazy matrices */
1280       {
1281         PetscInt    Istart,Iend,ncols,jj,Ii;
1282         PetscScalar zero = 0.0;
1283         ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1284         for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
1285           ierr = MatGetRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1286           if (ncols <= 1) {
1287             ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
1288           }
1289           ierr = MatRestoreRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1290         }
1291         ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
1292         ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
1293       }
1294 
1295       ierr = KSPCreate(comm,&eksp);CHKERRQ(ierr);
1296       ierr = KSPSetTolerances(eksp,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,10);CHKERRQ(ierr);
1297       ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
1298       ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
1299       ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
1300       ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
1301 
1302       ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
1303       ierr = KSPSetOperators(eksp, Amat, Amat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1304       ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
1305 
1306       ierr = KSPGetPC(eksp, &epc);CHKERRQ(ierr);
1307       ierr = PCSetType(epc, PCJACOBI);CHKERRQ(ierr);  /* smoother in smoothed agg. */
1308 
1309       /* solve - keep stuff out of logging */
1310       ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
1311       ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
1312       ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
1313       ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
1314       ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
1315 
1316       ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
1317       if (verbose > 0) {
1318         PetscPrintf(comm,"\t\t\t%s smooth P0: max eigen=%e min=%e PC=%s\n",
1319                     __FUNCT__,emax,emin,PCJACOBI);
1320       }
1321       ierr = VecDestroy(&xx);CHKERRQ(ierr);
1322       ierr = VecDestroy(&bb);CHKERRQ(ierr);
1323       ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
1324 
1325       if (pc_gamg->emax_id == -1) {
1326         ierr = PetscObjectComposedDataRegister(&pc_gamg->emax_id);CHKERRQ(ierr);
1327         if (pc_gamg->emax_id == -1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"pc_gamg->emax_id == -1");
1328       }
1329       ierr = PetscObjectComposedDataSetScalar((PetscObject)Amat, pc_gamg->emax_id, emax);CHKERRQ(ierr);
1330     }
1331 
1332     /* smooth P1 := (I - omega/lam D^{-1}A)P0 */
1333     ierr  = MatMatMult(Amat, Prol, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &tMat);CHKERRQ(ierr);
1334     ierr  = MatGetVecs(Amat, &diag, 0);CHKERRQ(ierr);
1335     ierr  = MatGetDiagonal(Amat, diag);CHKERRQ(ierr); /* effectively PCJACOBI */
1336     ierr  = VecReciprocal(diag);CHKERRQ(ierr);
1337     ierr  = MatDiagonalScale(tMat, diag, 0);CHKERRQ(ierr);
1338     ierr  = VecDestroy(&diag);CHKERRQ(ierr);
1339     alpha = -1.4/emax;
1340     ierr  = MatAYPX(tMat, alpha, Prol, SUBSET_NONZERO_PATTERN);CHKERRQ(ierr);
1341     ierr  = MatDestroy(&Prol);CHKERRQ(ierr);
1342     Prol  = tMat;
1343 #if defined PETSC_GAMG_USE_LOG
1344     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1345 #endif
1346   }
1347 #if defined PETSC_USE_LOG
1348   ierr = PetscLogEventEnd(PC_GAMGOptprol_AGG,0,0,0,0);CHKERRQ(ierr);
1349 #endif
1350   *a_P = Prol;
1351   PetscFunctionReturn(0);
1352 }
1353 
1354 /* -------------------------------------------------------------------------- */
1355 /*
1356    PCGAMGKKTProl_AGG
1357 
1358   Input Parameter:
1359    . pc - this
1360    . Prol11 - matrix on this fine level
1361    . A21 - matrix on this fine level
1362  In/Output Parameter:
1363    . a_P22 - prolongation operator to the next level
1364 */
1365 #undef __FUNCT__
1366 #define __FUNCT__ "PCGAMGKKTProl_AGG"
1367 PetscErrorCode PCGAMGKKTProl_AGG(PC pc,const Mat Prol11,const Mat A21,Mat *a_P22)
1368 {
1369   PetscErrorCode   ierr;
1370   PC_MG            *mg      = (PC_MG*)pc->data;
1371   PC_GAMG          *pc_gamg = (PC_GAMG*)mg->innerctx;
1372   const PetscInt   verbose  = pc_gamg->verbose;
1373   /* PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;  */
1374   PetscMPIInt      rank,size;
1375   Mat              Prol22,Tmat,Gmat;
1376   MPI_Comm         comm;
1377   PetscCoarsenData *agg_lists;
1378 
1379   PetscFunctionBegin;
1380   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1381 #if defined PETSC_USE_LOG
1382   ierr = PetscLogEventBegin(PC_GAMGKKTProl_AGG,0,0,0,0);CHKERRQ(ierr);
1383 #endif
1384   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1385   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1386 
1387   /* form C graph */
1388   ierr = MatMatMult(A21, Prol11, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Tmat);CHKERRQ(ierr);
1389   ierr = MatMatTransposeMult(Tmat, Tmat, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat);CHKERRQ(ierr);
1390   ierr = MatDestroy(&Tmat);CHKERRQ(ierr);
1391   ierr = PCGAMGFilterGraph(&Gmat, 0.0, PETSC_FALSE, verbose);CHKERRQ(ierr);
1392 
1393   /* coarsen constraints */
1394   {
1395     MatCoarsen crs;
1396     ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
1397     ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr);
1398     ierr = MatCoarsenSetAdjacency(crs, Gmat);CHKERRQ(ierr);
1399     ierr = MatCoarsenSetVerbose(crs, verbose);CHKERRQ(ierr);
1400     ierr = MatCoarsenSetStrictAggs(crs, PETSC_TRUE);CHKERRQ(ierr);
1401     ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
1402     ierr = MatCoarsenGetData(crs, &agg_lists);CHKERRQ(ierr);
1403     ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
1404   }
1405 
1406   /* form simple prolongation 'Prol22' */
1407   {
1408     PetscInt    ii,mm,clid,my0,nloc,nLocalSelected;
1409     PetscScalar val = 1.0;
1410     /* get 'nLocalSelected' */
1411     ierr = MatGetLocalSize(Gmat, &nloc, &ii);CHKERRQ(ierr);
1412     for (ii=0, nLocalSelected = 0; ii < nloc; ii++) {
1413       PetscBool ise;
1414       /* filter out singletons 0 or 1? */
1415       ierr = PetscCDEmptyAt(agg_lists, ii, &ise);CHKERRQ(ierr);
1416       if (!ise) nLocalSelected++;
1417     }
1418 
1419     ierr = MatCreate(comm,&Prol22);CHKERRQ(ierr);
1420     ierr = MatSetSizes(Prol22,nloc, nLocalSelected,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
1421     ierr = MatSetType(Prol22, MATAIJ);CHKERRQ(ierr);
1422     ierr = MatSeqAIJSetPreallocation(Prol22,1,NULL);CHKERRQ(ierr);
1423     ierr = MatMPIAIJSetPreallocation(Prol22,1,NULL,1,NULL);CHKERRQ(ierr);
1424     /* ierr = MatCreateAIJ(comm, */
1425     /*                      nloc, nLocalSelected, */
1426     /*                      PETSC_DETERMINE, PETSC_DETERMINE, */
1427     /*                      1, NULL, 1, NULL, */
1428     /*                      &Prol22); */
1429 
1430     ierr = MatGetOwnershipRange(Prol22, &my0, &ii);CHKERRQ(ierr);
1431     nloc = ii - my0;
1432 
1433     /* make aggregates */
1434     for (mm = clid = 0; mm < nloc; mm++) {
1435       ierr = PetscCDSizeAt(agg_lists, mm, &ii);CHKERRQ(ierr);
1436       if (ii > 0) {
1437         PetscInt   asz=ii,cgid=my0+clid,rids[1000];
1438         PetscCDPos pos;
1439         if (asz>1000) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Very large aggregate: %d",asz);
1440         ii   = 0;
1441         ierr = PetscCDGetHeadPos(agg_lists,mm,&pos);CHKERRQ(ierr);
1442         while (pos) {
1443           PetscInt gid1;
1444           ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
1445           ierr = PetscCDGetNextPos(agg_lists,mm,&pos);CHKERRQ(ierr);
1446 
1447           rids[ii++] = gid1;
1448         }
1449         if (ii != asz) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D != asz %D",ii,asz);
1450         /* add diagonal block of P0 */
1451         ierr = MatSetValues(Prol22,asz,rids,1,&cgid,&val,INSERT_VALUES);CHKERRQ(ierr);
1452 
1453         clid++;
1454       } /* coarse agg */
1455     } /* for all fine nodes */
1456     ierr = MatAssemblyBegin(Prol22,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1457     ierr = MatAssemblyEnd(Prol22,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1458   }
1459 
1460   /* clean up */
1461   ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
1462   ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
1463 #if defined PETSC_USE_LOG
1464   ierr = PetscLogEventEnd(PC_GAMGKKTProl_AGG,0,0,0,0);CHKERRQ(ierr);
1465 #endif
1466   *a_P22 = Prol22;
1467   PetscFunctionReturn(0);
1468 }
1469 
1470 /* -------------------------------------------------------------------------- */
1471 /*
1472    PCCreateGAMG_AGG
1473 
1474   Input Parameter:
1475    . pc -
1476 */
1477 #undef __FUNCT__
1478 #define __FUNCT__ "PCCreateGAMG_AGG"
1479 PetscErrorCode  PCCreateGAMG_AGG(PC pc)
1480 {
1481   PetscErrorCode ierr;
1482   PC_MG          *mg      = (PC_MG*)pc->data;
1483   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1484   PC_GAMG_AGG    *pc_gamg_agg;
1485 
1486   PetscFunctionBegin;
1487   if (pc_gamg->subctx) {
1488     /* call base class */
1489     ierr = PCDestroy_GAMG(pc);CHKERRQ(ierr);
1490   }
1491 
1492   /* create sub context for SA */
1493   ierr            = PetscNewLog(pc, PC_GAMG_AGG, &pc_gamg_agg);CHKERRQ(ierr);
1494   pc_gamg->subctx = pc_gamg_agg;
1495 
1496   pc_gamg->setfromoptions = PCSetFromOptions_GAMG_AGG;
1497   pc->ops->destroy        = PCDestroy_AGG;
1498   /* reset does not do anything; setup not virtual */
1499 
1500   /* set internal function pointers */
1501   pc_gamg->graph       = PCGAMGgraph_AGG;
1502   pc_gamg->coarsen     = PCGAMGCoarsen_AGG;
1503   pc_gamg->prolongator = PCGAMGProlongator_AGG;
1504   pc_gamg->optprol     = PCGAMGOptprol_AGG;
1505   pc_gamg->formkktprol = PCGAMGKKTProl_AGG;
1506 
1507   pc_gamg->createdefaultdata = PCSetData_AGG;
1508 
1509   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",PCSetCoordinates_AGG);CHKERRQ(ierr);
1510   PetscFunctionReturn(0);
1511 }
1512