xref: /petsc/src/ksp/pc/impls/gamg/agg.c (revision 5c8f6a953e7ed1c81f507d64aebddb11080b60e9)
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 <assert.h>
9 #include <petscblaslapack.h>
10 
11 typedef struct {
12   PetscInt nsmooths;
13   PetscBool sym_graph;
14   PetscBool square_graph;
15 }PC_GAMG_AGG;
16 
17 #undef __FUNCT__
18 #define __FUNCT__ "PCGAMGSetNSmooths"
19 /*@
20    PCGAMGSetNSmooths - Set number of smoothing steps (1 is typical)
21 
22    Not Collective on PC
23 
24    Input Parameters:
25 .  pc - the preconditioner context
26 
27    Options Database Key:
28 .  -pc_gamg_agg_nsmooths
29 
30    Level: intermediate
31 
32    Concepts: Aggregation AMG preconditioner
33 
34 .seealso: ()
35 @*/
36 PetscErrorCode PCGAMGSetNSmooths(PC pc, PetscInt n)
37 {
38   PetscErrorCode ierr;
39 
40   PetscFunctionBegin;
41   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
42   ierr = PetscTryMethod(pc,"PCGAMGSetNSmooths_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
43   PetscFunctionReturn(0);
44 }
45 
46 EXTERN_C_BEGIN
47 #undef __FUNCT__
48 #define __FUNCT__ "PCGAMGSetNSmooths_GAMG"
49 PetscErrorCode PCGAMGSetNSmooths_GAMG(PC pc, PetscInt n)
50 {
51   PC_MG           *mg = (PC_MG*)pc->data;
52   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
53   PC_GAMG_AGG     *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
54 
55   PetscFunctionBegin;
56   pc_gamg_agg->nsmooths = n;
57   PetscFunctionReturn(0);
58 }
59 EXTERN_C_END
60 
61 #undef __FUNCT__
62 #define __FUNCT__ "PCGAMGSetSymGraph"
63 /*@
64    PCGAMGSetSymGraph -
65 
66    Not Collective on PC
67 
68    Input Parameters:
69 .  pc - the preconditioner context
70 
71    Options Database Key:
72 .  -pc_gamg_sym_graph
73 
74    Level: intermediate
75 
76    Concepts: Aggregation AMG preconditioner
77 
78 .seealso: ()
79 @*/
80 PetscErrorCode PCGAMGSetSymGraph(PC pc, PetscBool n)
81 {
82   PetscErrorCode ierr;
83 
84   PetscFunctionBegin;
85   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
86   ierr = PetscTryMethod(pc,"PCGAMGSetSymGraph_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
87   PetscFunctionReturn(0);
88 }
89 
90 EXTERN_C_BEGIN
91 #undef __FUNCT__
92 #define __FUNCT__ "PCGAMGSetSymGraph_GAMG"
93 PetscErrorCode PCGAMGSetSymGraph_GAMG(PC pc, PetscBool n)
94 {
95   PC_MG           *mg = (PC_MG*)pc->data;
96   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
97   PC_GAMG_AGG      *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
98 
99   PetscFunctionBegin;
100   pc_gamg_agg->sym_graph = n;
101   PetscFunctionReturn(0);
102 }
103 EXTERN_C_END
104 
105 #undef __FUNCT__
106 #define __FUNCT__ "PCGAMGSetSquareGraph"
107 /*@
108    PCGAMGSetSquareGraph -
109 
110    Not Collective on PC
111 
112    Input Parameters:
113 .  pc - the preconditioner context
114 
115    Options Database Key:
116 .  -pc_gamg_square_graph
117 
118    Level: intermediate
119 
120    Concepts: Aggregation AMG preconditioner
121 
122 .seealso: ()
123 @*/
124 PetscErrorCode PCGAMGSetSquareGraph(PC pc, PetscBool n)
125 {
126   PetscErrorCode ierr;
127 
128   PetscFunctionBegin;
129   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
130   ierr = PetscTryMethod(pc,"PCGAMGSetSquareGraph_C",(PC,PetscBool),(pc,n));CHKERRQ(ierr);
131   PetscFunctionReturn(0);
132 }
133 
134 EXTERN_C_BEGIN
135 #undef __FUNCT__
136 #define __FUNCT__ "PCGAMGSetSquareGraph_GAMG"
137 PetscErrorCode PCGAMGSetSquareGraph_GAMG(PC pc, PetscBool n)
138 {
139   PC_MG           *mg = (PC_MG*)pc->data;
140   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
141   PC_GAMG_AGG      *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
142 
143   PetscFunctionBegin;
144   pc_gamg_agg->square_graph = n;
145   PetscFunctionReturn(0);
146 }
147 EXTERN_C_END
148 
149 /* -------------------------------------------------------------------------- */
150 /*
151    PCSetFromOptions_GAMG_AGG
152 
153   Input Parameter:
154    . pc -
155 */
156 #undef __FUNCT__
157 #define __FUNCT__ "PCSetFromOptions_GAMG_AGG"
158 PetscErrorCode PCSetFromOptions_GAMG_AGG(PC pc)
159 {
160   PetscErrorCode  ierr;
161   PC_MG           *mg = (PC_MG*)pc->data;
162   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
163   PC_GAMG_AGG      *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
164   PetscBool        flag;
165 
166   PetscFunctionBegin;
167   /* call base class */
168   ierr = PCSetFromOptions_GAMG(pc);CHKERRQ(ierr);
169 
170   ierr = PetscOptionsHead("GAMG-AGG options");CHKERRQ(ierr);
171   {
172     /* -pc_gamg_agg_nsmooths */
173     pc_gamg_agg->nsmooths = 0;
174     ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths",
175                            "smoothing steps for smoothed aggregation, usually 1 (0)",
176                            "PCGAMGSetNSmooths",
177                            pc_gamg_agg->nsmooths,
178                            &pc_gamg_agg->nsmooths,
179                            &flag);CHKERRQ(ierr);
180 
181     /* -pc_gamg_sym_graph */
182     pc_gamg_agg->sym_graph = PETSC_FALSE;
183     ierr = PetscOptionsBool("-pc_gamg_sym_graph",
184                             "Set for asymmetric matrices",
185                             "PCGAMGSetSymGraph",
186                             pc_gamg_agg->sym_graph,
187                             &pc_gamg_agg->sym_graph,
188                             &flag);CHKERRQ(ierr);
189 
190     /* -pc_gamg_square_graph */
191     pc_gamg_agg->square_graph = PETSC_TRUE;
192     ierr = PetscOptionsBool("-pc_gamg_square_graph",
193                             "For faster coarsening and lower coarse grid complexity",
194                             "PCGAMGSetSquareGraph",
195                             pc_gamg_agg->square_graph,
196                             &pc_gamg_agg->square_graph,
197                             &flag);CHKERRQ(ierr);
198   }
199   ierr = PetscOptionsTail();CHKERRQ(ierr);
200 
201   PetscFunctionReturn(0);
202 }
203 
204 /* -------------------------------------------------------------------------- */
205 /*
206    PCDestroy_AGG
207 
208   Input Parameter:
209    . pc -
210 */
211 #undef __FUNCT__
212 #define __FUNCT__ "PCDestroy_AGG"
213 PetscErrorCode PCDestroy_AGG(PC pc)
214 {
215   PetscErrorCode  ierr;
216   PC_MG           *mg = (PC_MG*)pc->data;
217   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
218   PC_GAMG_AGG      *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
219 
220   PetscFunctionBegin;
221   if (pc_gamg_agg) {
222     ierr = PetscFree(pc_gamg_agg);CHKERRQ(ierr);
223     pc_gamg_agg = 0;
224   }
225 
226   /* call base class */
227   ierr = PCDestroy_GAMG(pc);CHKERRQ(ierr);
228 
229   PetscFunctionReturn(0);
230 }
231 
232 /* -------------------------------------------------------------------------- */
233 /*
234    PCSetCoordinates_AGG
235      - collective
236 
237    Input Parameter:
238    . pc - the preconditioner context
239    . ndm - dimesion of data (used for dof/vertex for Stokes)
240    . a_nloc - number of vertices local
241    . coords - [a_nloc][ndm] - interleaved coordinate data: {x_0, y_0, z_0, x_1, y_1, ...}
242 */
243 EXTERN_C_BEGIN
244 #undef __FUNCT__
245 #define __FUNCT__ "PCSetCoordinates_AGG"
246 PetscErrorCode PCSetCoordinates_AGG(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
247 {
248   PC_MG          *mg = (PC_MG*)pc->data;
249   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
250   PetscErrorCode  ierr;
251   PetscInt        arrsz,kk,ii,jj,nloc,ndatarows,ndf;
252   Mat             mat = pc->pmat;
253   /* MPI_Comm     wcomm = ((PetscObject)pc)->comm; */
254 
255   PetscFunctionBegin;
256   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
257   PetscValidHeaderSpecific(mat,MAT_CLASSID,1);
258   nloc = a_nloc;
259 
260   /* SA: null space vectors */
261   ierr = MatGetBlockSize(mat, &ndf);CHKERRQ(ierr); /* this does not work for Stokes */
262   if (coords && ndf==1) pc_gamg->data_cell_cols = 1; /* scalar w/ coords and SA (not needed) */
263   else if (coords) {
264     if (ndm > ndf) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"degrees of motion %d > block size %d",ndm,ndf);
265     pc_gamg->data_cell_cols = (ndm==2 ? 3 : 6); /* displacement elasticity */
266     if (ndm != ndf) {
267       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);
268     }
269   } else pc_gamg->data_cell_cols = ndf; /* no data, force SA with constant null space vectors */
270   pc_gamg->data_cell_rows = ndatarows = ndf;     assert(pc_gamg->data_cell_cols>0);
271   arrsz = nloc*pc_gamg->data_cell_rows*pc_gamg->data_cell_cols;
272 
273   /* create data - syntactic sugar that should be refactored at some point */
274   if (pc_gamg->data==0 || (pc_gamg->data_sz != arrsz)) {
275     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
276     ierr = PetscMalloc((arrsz+1)*sizeof(PetscReal), &pc_gamg->data);CHKERRQ(ierr);
277   }
278   /* copy data in - column oriented */
279   for (kk=0;kk<nloc;kk++) {
280     const PetscInt M = nloc*pc_gamg->data_cell_rows; /* stride into data */
281     PetscReal *data = &pc_gamg->data[kk*ndatarows]; /* start of cell */
282     if (pc_gamg->data_cell_cols==1) *data = 1.0;
283     else {
284       /* translational modes */
285       for (ii=0;ii<ndatarows;ii++)
286         for (jj=0;jj<ndatarows;jj++)
287           if (ii==jj)data[ii*M + jj] = 1.0;
288           else data[ii*M + jj] = 0.0;
289 
290       /* rotational modes */
291       if (coords) {
292         if (ndm == 2) {
293           data += 2*M;
294           data[0] = -coords[2*kk+1];
295           data[1] =  coords[2*kk];
296         } else {
297           data += 3*M;
298           data[0] = 0.0;             data[M+0] =  coords[3*kk+2]; data[2*M+0] = -coords[3*kk+1];
299           data[1] = -coords[3*kk+2]; data[M+1] = 0.0;             data[2*M+1] =  coords[3*kk];
300           data[2] =  coords[3*kk+1]; data[M+2] = -coords[3*kk];   data[2*M+2] = 0.0;
301         }
302       }
303     }
304   }
305 
306   pc_gamg->data_sz = arrsz;
307 
308   PetscFunctionReturn(0);
309 }
310 EXTERN_C_END
311 
312 typedef PetscInt NState;
313 static const NState NOT_DONE=-2;
314 static const NState DELETED=-1;
315 static const NState REMOVED=-3;
316 #define IS_SELECTED(s) (s!=DELETED && s!=NOT_DONE && s!=REMOVED)
317 
318 /* -------------------------------------------------------------------------- */
319 /*
320    smoothAggs - greedy grab of with G1 (unsquared graph) -- AIJ specific
321      - AGG-MG specific: clears singletons out of 'selected_2'
322 
323    Input Parameter:
324    . Gmat_2 - glabal matrix of graph (data not defined)
325    . Gmat_1 - base graph to grab with
326    Input/Output Parameter:
327    . aggs_2 - linked list of aggs with gids)
328 */
329 #undef __FUNCT__
330 #define __FUNCT__ "smoothAggs"
331 static PetscErrorCode smoothAggs(const Mat Gmat_2, /* base (squared) graph */
332                                   const Mat Gmat_1, /* base graph */
333                                   /* const IS selected_2, [nselected local] selected vertices */
334                                   PetscCoarsenData *aggs_2) /* [nselected local] global ID of aggregate */
335 {
336   PetscErrorCode ierr;
337   PetscBool      isMPI;
338   Mat_SeqAIJ    *matA_1, *matB_1=0, *matA_2, *matB_2=0;
339   MPI_Comm       wcomm = ((PetscObject)Gmat_2)->comm;
340   PetscMPIInt    mype,npe;
341   PetscInt       lid,*ii,*idx,ix,Iend,my0,kk,n,j;
342   Mat_MPIAIJ    *mpimat_2 = 0, *mpimat_1=0;
343   const PetscInt nloc = Gmat_2->rmap->n;
344   PetscScalar   *cpcol_1_state,*cpcol_2_state,*cpcol_2_par_orig,*lid_parent_gid;
345   PetscInt      *lid_cprowID_1;
346   NState        *lid_state;
347   Vec            ghost_par_orig2;
348 
349   PetscFunctionBegin;
350   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
351   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
352   ierr = MatGetOwnershipRange(Gmat_1,&my0,&Iend);CHKERRQ(ierr);
353 
354   if (PETSC_FALSE) {
355     PetscViewer viewer; char fname[32]; static int llev=0;
356     sprintf(fname,"Gmat2_%d.m",llev++);
357     PetscViewerASCIIOpen(wcomm,fname,&viewer);
358     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
359     ierr = MatView(Gmat_2, viewer);CHKERRQ(ierr);
360     ierr = PetscViewerDestroy(&viewer);
361   }
362 
363   /* get submatrices */
364   ierr = PetscObjectTypeCompare((PetscObject)Gmat_1, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
365   if (isMPI) {
366     /* grab matrix objects */
367     mpimat_2 = (Mat_MPIAIJ*)Gmat_2->data;
368     mpimat_1 = (Mat_MPIAIJ*)Gmat_1->data;
369     matA_1 = (Mat_SeqAIJ*)mpimat_1->A->data;
370     matB_1 = (Mat_SeqAIJ*)mpimat_1->B->data;
371     matA_2 = (Mat_SeqAIJ*)mpimat_2->A->data;
372     matB_2 = (Mat_SeqAIJ*)mpimat_2->B->data;
373 
374     /* force compressed row storage for B matrix in AuxMat */
375     matB_1->compressedrow.check = PETSC_TRUE;
376     ierr = MatCheckCompressedRow(mpimat_1->B,&matB_1->compressedrow,matB_1->i,Gmat_1->rmap->n,-1.0);CHKERRQ(ierr);
377 
378     ierr = PetscMalloc(nloc*sizeof(PetscInt), &lid_cprowID_1);CHKERRQ(ierr);
379     for (lid = 0 ; lid < nloc ; lid++) lid_cprowID_1[lid] = -1;
380     for (ix=0; ix<matB_1->compressedrow.nrows; ix++) {
381       PetscInt lid = matB_1->compressedrow.rindex[ix];
382       lid_cprowID_1[lid] = ix;
383     }
384   } else {
385     matA_1 = (Mat_SeqAIJ*)Gmat_1->data;
386     matA_2 = (Mat_SeqAIJ*)Gmat_2->data;
387     lid_cprowID_1 = PETSC_NULL;
388   }
389   assert(matA_1 && !matA_1->compressedrow.use);
390   assert(matB_1==0 || matB_1->compressedrow.use);
391   assert(matA_2 && !matA_2->compressedrow.use);
392   assert(matB_2==0 || matB_2->compressedrow.use);
393 
394   /* get state of locals and selected gid for deleted */
395   ierr = PetscMalloc(nloc*sizeof(NState), &lid_state);CHKERRQ(ierr);
396   ierr = PetscMalloc(nloc*sizeof(PetscScalar), &lid_parent_gid);CHKERRQ(ierr);
397   for (lid = 0 ; lid < nloc ; lid++) {
398     lid_parent_gid[lid] = -1.0;
399     lid_state[lid] = DELETED;
400   }
401 
402   /* set lid_state */
403   for (lid = 0 ; lid < nloc ; lid++) {
404     PetscCDPos pos;
405     ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
406     if (pos) {
407       PetscInt gid1;
408       ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr); assert(gid1==lid+my0);
409       lid_state[lid] = gid1;
410     }
411   }
412 
413   /* map local to selected local, DELETED means a ghost owns it */
414   for (lid=kk=0;lid<nloc;lid++) {
415     NState state = lid_state[lid];
416     if (IS_SELECTED(state)) {
417       PetscCDPos pos;
418       ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
419       while (pos) {
420         PetscInt gid1;
421         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
422         ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
423 
424         if (gid1 >= my0 && gid1 < Iend) {
425           lid_parent_gid[gid1-my0] = (PetscScalar)(lid + my0);
426         }
427       }
428     }
429   }
430   /* get 'cpcol_1/2_state' & cpcol_2_par_orig - uses mpimat_1/2->lvec for temp space */
431   if (isMPI) {
432     Vec          tempVec;
433     /* get 'cpcol_1_state' */
434     ierr = MatGetVecs(Gmat_1, &tempVec, 0);CHKERRQ(ierr);
435     for (kk=0,j=my0;kk<nloc;kk++,j++) {
436       PetscScalar v = (PetscScalar)lid_state[kk];
437       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
438     }
439     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
440     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
441     ierr = VecScatterBegin(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
442     ierr =   VecScatterEnd(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
443     ierr = VecGetArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
444     /* get 'cpcol_2_state' */
445     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
446     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
447     ierr = VecGetArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
448     /* get 'cpcol_2_par_orig' */
449     for (kk=0,j=my0;kk<nloc;kk++,j++) {
450       PetscScalar v = (PetscScalar)lid_parent_gid[kk];
451       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
452     }
453     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
454     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
455     ierr = VecDuplicate(mpimat_2->lvec, &ghost_par_orig2);CHKERRQ(ierr);
456     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
457     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
458     ierr = VecGetArray(ghost_par_orig2, &cpcol_2_par_orig);CHKERRQ(ierr);
459 
460     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
461   } /* ismpi */
462 
463   /* doit */
464   for (lid=0;lid<nloc;lid++) {
465     NState state = lid_state[lid];
466     if (IS_SELECTED(state)) {
467       /* steal locals */
468       ii = matA_1->i; n = ii[lid+1] - ii[lid];
469       idx = matA_1->j + ii[lid];
470       for (j=0; j<n; j++) {
471         PetscInt lidj = idx[j], sgid;
472         NState statej = lid_state[lidj];
473         if (statej==DELETED && (sgid=(PetscInt)PetscRealPart(lid_parent_gid[lidj])) != lid+my0) { /* steal local */
474           lid_parent_gid[lidj] = (PetscScalar)(lid+my0); /* send this if sgid is not local */
475           if (sgid >= my0 && sgid < Iend) {       /* I'm stealing this local from a local sgid */
476             PetscInt hav=0,slid=sgid-my0,gidj=lidj+my0;
477             PetscCDPos pos,last=PETSC_NULL;
478             /* looking for local from local so id_llist_2 works */
479             ierr = PetscCDGetHeadPos(aggs_2,slid,&pos);CHKERRQ(ierr);
480             while (pos) {
481               PetscInt gid;
482               ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
483               if (gid == gidj) {
484                 assert(last);
485                 ierr = PetscCDRemoveNextNode(aggs_2, slid, last);CHKERRQ(ierr);
486                 ierr = PetscCDAppendNode(aggs_2, lid, pos);CHKERRQ(ierr);
487                 hav = 1;
488                 break;
489               } else last = pos;
490 
491               ierr = PetscCDGetNextPos(aggs_2,slid,&pos);CHKERRQ(ierr);
492             }
493             if (hav!=1) {
494               if (hav==0)SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
495               SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
496             }
497           } else {            /* I'm stealing this local, owned by a ghost */
498             if (sgid != -1) {
499               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.");
500             }
501             ierr = PetscCDAppendID(aggs_2, lid, lidj+my0);CHKERRQ(ierr);
502           }
503         }
504       } /* local neighbors */
505     } else if (state == DELETED && lid_cprowID_1) {
506       PetscInt sgidold = (PetscInt)PetscRealPart(lid_parent_gid[lid]);
507       /* see if I have a selected ghost neighbor that will steal me */
508       if ((ix=lid_cprowID_1[lid]) != -1) {
509         ii = matB_1->compressedrow.i; n = ii[ix+1] - ii[ix];
510         idx = matB_1->j + ii[ix];
511         for (j=0 ; j<n ; j++) {
512           PetscInt cpid = idx[j];
513           NState statej = (NState)PetscRealPart(cpcol_1_state[cpid]);
514           if (IS_SELECTED(statej) && sgidold != (PetscInt)statej) { /* ghost will steal this, remove from my list */
515             lid_parent_gid[lid] = (PetscScalar)statej; /* send who selected */
516             if (sgidold>=my0 && sgidold<Iend) { /* this was mine */
517               PetscInt hav=0,oldslidj=sgidold-my0;
518               PetscCDPos pos,last=PETSC_NULL;
519               /* remove from 'oldslidj' list */
520               ierr = PetscCDGetHeadPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
521               while (pos) {
522                 PetscInt gid;
523                 ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
524                 if (lid+my0 == gid) {
525                   /* id_llist_2[lastid] = id_llist_2[flid];   /\* remove lid from oldslidj list *\/ */
526                   assert(last);
527                   ierr = PetscCDRemoveNextNode(aggs_2, oldslidj, last);CHKERRQ(ierr);
528                   /* ghost (PetscScalar)statej will add this later */
529                   hav = 1;
530                   break;
531                 } else last = pos;
532 
533                 ierr = PetscCDGetNextPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
534               }
535               if (hav!=1) {
536                 if (hav==0)SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
537                 SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
538               }
539             } else {
540               /* ghosts remove this later */
541             }
542           }
543         }
544       }
545     } /* selected/deleted */
546   } /* node loop */
547 
548   if (isMPI) {
549     PetscScalar *cpcol_2_parent,*cpcol_2_gid;
550     Vec          tempVec,ghostgids2,ghostparents2;
551     PetscInt     cpid,nghost_2;
552     GAMGHashTable gid_cpid;
553 
554     ierr = VecGetSize(mpimat_2->lvec, &nghost_2);CHKERRQ(ierr);
555     ierr = MatGetVecs(Gmat_2, &tempVec, 0);CHKERRQ(ierr);
556 
557     /* get 'cpcol_2_parent' */
558     for (kk=0,j=my0;kk<nloc;kk++,j++) {
559       ierr = VecSetValues(tempVec, 1, &j, &lid_parent_gid[kk], INSERT_VALUES);CHKERRQ(ierr);
560     }
561     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
562     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
563     ierr = VecDuplicate(mpimat_2->lvec, &ghostparents2);CHKERRQ(ierr);
564     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
565     ierr = VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
566     ierr = VecGetArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
567 
568     /* get 'cpcol_2_gid' */
569     for (kk=0,j=my0;kk<nloc;kk++,j++) {
570       PetscScalar v = (PetscScalar)j;
571       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
572     }
573     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
574     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
575     ierr = VecDuplicate(mpimat_2->lvec, &ghostgids2);CHKERRQ(ierr);
576     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
577     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
578     ierr = VecGetArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
579 
580     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
581 
582     /* look for deleted ghosts and add to table */
583     ierr = GAMGTableCreate(2*nghost_2+1, &gid_cpid);CHKERRQ(ierr);
584     for (cpid = 0 ; cpid < nghost_2 ; cpid++) {
585       NState state = (NState)PetscRealPart(cpcol_2_state[cpid]);
586       if (state==DELETED) {
587         PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
588         PetscInt sgid_old = (PetscInt)PetscRealPart(cpcol_2_par_orig[cpid]);
589         if (sgid_old == -1 && sgid_new != -1) {
590           PetscInt gid = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
591           ierr = GAMGTableAdd(&gid_cpid, gid, cpid);CHKERRQ(ierr);
592         }
593       }
594     }
595 
596     /* look for deleted ghosts and see if they moved - remove it */
597     for (lid=0;lid<nloc;lid++) {
598       NState state = lid_state[lid];
599       if (IS_SELECTED(state)) {
600         PetscCDPos pos,last=PETSC_NULL;
601         /* look for deleted ghosts and see if they moved */
602         ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
603         while (pos) {
604           PetscInt gid;
605           ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
606 
607           if (gid < my0 || gid >= Iend) {
608             ierr = GAMGTableFind(&gid_cpid, gid, &cpid);CHKERRQ(ierr);
609             if (cpid != -1) {
610               /* a moved ghost - */
611               /* id_llist_2[lastid] = id_llist_2[flid];    /\* remove 'flid' from list *\/ */
612               ierr = PetscCDRemoveNextNode(aggs_2, lid, last);CHKERRQ(ierr);
613             } else last = pos;
614           } else last = pos;
615 
616           ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
617         } /* loop over list of deleted */
618       } /* selected */
619     }
620     ierr = GAMGTableDestroy(&gid_cpid);CHKERRQ(ierr);
621 
622     /* look at ghosts, see if they changed - and it */
623     for (cpid = 0 ; cpid < nghost_2 ; cpid++) {
624       PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
625       if (sgid_new >= my0 && sgid_new < Iend) { /* this is mine */
626         PetscInt gid = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
627         PetscInt slid_new=sgid_new-my0,hav=0;
628         PetscCDPos pos;
629         /* search for this gid to see if I have it */
630         ierr = PetscCDGetHeadPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
631         while (pos) {
632           PetscInt gidj;
633           ierr = PetscLLNGetID(pos, &gidj);CHKERRQ(ierr);
634           ierr = PetscCDGetNextPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
635 
636           if (gidj == gid) { hav = 1; break; }
637         }
638         if (hav != 1) {
639           /* insert 'flidj' into head of llist */
640           ierr = PetscCDAppendID(aggs_2, slid_new, gid);CHKERRQ(ierr);
641         }
642       }
643     }
644 
645     ierr = VecRestoreArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
646     ierr = VecRestoreArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
647     ierr = VecRestoreArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
648     ierr = VecRestoreArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
649     ierr = PetscFree(lid_cprowID_1);CHKERRQ(ierr);
650     ierr = VecDestroy(&ghostgids2);CHKERRQ(ierr);
651     ierr = VecDestroy(&ghostparents2);CHKERRQ(ierr);
652     ierr = VecDestroy(&ghost_par_orig2);CHKERRQ(ierr);
653   }
654 
655   ierr = PetscFree(lid_parent_gid);CHKERRQ(ierr);
656   ierr = PetscFree(lid_state);CHKERRQ(ierr);
657 
658   PetscFunctionReturn(0);
659 }
660 
661 /* -------------------------------------------------------------------------- */
662 /*
663    PCSetData_AGG - called if data is not set with PCSetCoordinates.
664       Looks in Mat for near null space.
665       Does not work for Stokes
666 
667   Input Parameter:
668    . pc -
669    . a_A - matrix to get (near) null space out of.
670 */
671 #undef __FUNCT__
672 #define __FUNCT__ "PCSetData_AGG"
673 PetscErrorCode PCSetData_AGG(PC pc, Mat a_A)
674 {
675   PetscErrorCode ierr;
676   PC_MG          *mg = (PC_MG*)pc->data;
677   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
678   MatNullSpace   mnull;
679 
680   PetscFunctionBegin;
681   ierr = MatGetNearNullSpace(a_A, &mnull);CHKERRQ(ierr);
682   if (!mnull) {
683     PetscInt bs,NN,MM;
684     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr);
685     ierr = MatGetLocalSize(a_A, &MM, &NN);CHKERRQ(ierr);  assert(MM%bs==0);
686     ierr = PCSetCoordinates_AGG(pc, bs, MM/bs, PETSC_NULL);CHKERRQ(ierr);
687   } else {
688     PetscReal *nullvec;
689     PetscBool has_const;
690     PetscInt  i,j,mlocal,nvec,bs;
691     const Vec *vecs; const PetscScalar *v;
692     ierr = MatGetLocalSize(a_A,&mlocal,PETSC_NULL);CHKERRQ(ierr);
693     ierr = MatNullSpaceGetVecs(mnull, &has_const, &nvec, &vecs);CHKERRQ(ierr);
694     ierr = PetscMalloc((nvec+!!has_const)*mlocal*sizeof(*nullvec),&nullvec);CHKERRQ(ierr);
695     if (has_const) for (i=0; i<mlocal; i++) nullvec[i] = 1.0;
696     for (i=0; i<nvec; i++) {
697       ierr = VecGetArrayRead(vecs[i],&v);CHKERRQ(ierr);
698       for (j=0; j<mlocal; j++) nullvec[(i+!!has_const)*mlocal + j] = PetscRealPart(v[j]);
699       ierr = VecRestoreArrayRead(vecs[i],&v);CHKERRQ(ierr);
700     }
701     pc_gamg->data = nullvec;
702     pc_gamg->data_cell_cols = (nvec+!!has_const);
703     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr); /* this does not work for Stokes */
704     pc_gamg->data_cell_rows = bs;
705   }
706   PetscFunctionReturn(0);
707 }
708 
709 /* -------------------------------------------------------------------------- */
710 /*
711  formProl0
712 
713    Input Parameter:
714    . agg_llists - list of arrays with aggregates
715    . bs - block size
716    . nSAvec - column bs of new P
717    . my0crs - global index of start of locals
718    . data_stride - bs*(nloc nodes + ghost nodes)
719    . data_in[data_stride*nSAvec] - local data on fine grid
720    . flid_fgid[data_stride/bs] - make local to global IDs, includes ghosts in 'locals_llist'
721   Output Parameter:
722    . a_data_out - in with fine grid data (w/ghosts), out with coarse grid data
723    . a_Prol - prolongation operator
724 */
725 #undef __FUNCT__
726 #define __FUNCT__ "formProl0"
727 static PetscErrorCode formProl0(const PetscCoarsenData *agg_llists,/* list from selected vertices of aggregate unselected vertices */
728                                 const PetscInt bs,          /* (row) block size */
729                                 const PetscInt nSAvec,      /* column bs */
730                                 const PetscInt my0crs,      /* global index of start of locals */
731                                 const PetscInt data_stride, /* (nloc+nghost)*bs */
732                                 PetscReal      data_in[],   /* [data_stride][nSAvec] */
733                                 const PetscInt flid_fgid[], /* [data_stride/bs] */
734                                 PetscReal **a_data_out,
735                                 Mat a_Prol) /* prolongation operator (output)*/
736 {
737   PetscErrorCode ierr;
738   PetscInt  Istart,my0,Iend,nloc,clid,flid,aggID,kk,jj,ii,mm,ndone,nSelected,minsz,nghosts,out_data_stride;
739   MPI_Comm       wcomm = ((PetscObject)a_Prol)->comm;
740   PetscMPIInt    mype, npe;
741   PetscReal      *out_data;
742   PetscCDPos         pos;
743   GAMGHashTable  fgid_flid;
744 
745 /* #define OUT_AGGS */
746 #if defined(OUT_AGGS)
747   static PetscInt llev = 0; char fname[32]; FILE *file = PETSC_NULL; PetscInt pM;
748 #endif
749 
750   PetscFunctionBegin;
751   ierr = MPI_Comm_rank(wcomm,&mype);CHKERRQ(ierr);
752   ierr = MPI_Comm_size(wcomm,&npe);CHKERRQ(ierr);
753   ierr = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
754   nloc = (Iend-Istart)/bs; my0 = Istart/bs; assert((Iend-Istart)%bs==0);
755   Iend /= bs;
756   nghosts = data_stride/bs - nloc;
757 
758   ierr = GAMGTableCreate(2*nghosts+1, &fgid_flid);CHKERRQ(ierr);
759   for (kk=0;kk<nghosts;kk++) {
760     ierr = GAMGTableAdd(&fgid_flid, flid_fgid[nloc+kk], nloc+kk);CHKERRQ(ierr);
761   }
762 
763 #if defined(OUT_AGGS)
764   sprintf(fname,"aggs_%d_%d.m",llev++,mype);
765   if (llev==1) {
766     file = fopen(fname,"w");
767   }
768   MatGetSize(a_Prol, &pM, &jj);
769 #endif
770 
771   /* count selected -- same as number of cols of P */
772   for (nSelected=mm=0;mm<nloc;mm++) {
773     PetscBool ise;
774     ierr = PetscCDEmptyAt(agg_llists, mm, &ise);CHKERRQ(ierr);
775     if (!ise) nSelected++;
776   }
777   ierr = MatGetOwnershipRangeColumn(a_Prol, &ii, &jj);CHKERRQ(ierr);
778   assert((ii/nSAvec)==my0crs); assert(nSelected==(jj-ii)/nSAvec);
779 
780   /* aloc space for coarse point data (output) */
781   out_data_stride = nSelected*nSAvec;
782   ierr = PetscMalloc(out_data_stride*nSAvec*sizeof(PetscReal), &out_data);CHKERRQ(ierr);
783   for (ii=0;ii<out_data_stride*nSAvec;ii++) {
784     out_data[ii]=1.e300;
785   }
786   *a_data_out = out_data; /* output - stride nSelected*nSAvec */
787 
788   /* find points and set prolongation */
789   minsz = 100;
790   ndone = 0;
791   for (mm = clid = 0 ; mm < nloc ; mm++) {
792     ierr = PetscCDSizeAt(agg_llists, mm, &jj);CHKERRQ(ierr);
793     if (jj > 0) {
794       const PetscInt lid = mm, cgid = my0crs + clid;
795       PetscInt cids[100]; /* max bs */
796       PetscBLASInt asz=jj,M=asz*bs,N=nSAvec,INFO;
797       PetscBLASInt   Mdata=M+((N-M>0)?N-M:0),LDA=Mdata,LWORK=N*bs;
798       PetscScalar    *qqc,*qqr,*TAU,*WORK;
799       PetscInt       *fids;
800       PetscReal      *data;
801       /* count agg */
802       if (asz<minsz) minsz = asz;
803 
804       /* get block */
805       ierr = PetscMalloc((Mdata*N)*sizeof(PetscScalar), &qqc);CHKERRQ(ierr);
806       ierr = PetscMalloc((M*N)*sizeof(PetscScalar), &qqr);CHKERRQ(ierr);
807       ierr = PetscMalloc(N*sizeof(PetscScalar), &TAU);CHKERRQ(ierr);
808       ierr = PetscMalloc(LWORK*sizeof(PetscScalar), &WORK);CHKERRQ(ierr);
809       ierr = PetscMalloc(M*sizeof(PetscInt), &fids);CHKERRQ(ierr);
810 
811       aggID = 0;
812       ierr = PetscCDGetHeadPos(agg_llists,lid,&pos);CHKERRQ(ierr);
813       while (pos) {
814         PetscInt gid1;
815         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
816         ierr = PetscCDGetNextPos(agg_llists,lid,&pos);CHKERRQ(ierr);
817 
818         if (gid1 >= my0 && gid1 < Iend) flid = gid1 - my0;
819         else {
820           ierr = GAMGTableFind(&fgid_flid, gid1, &flid);CHKERRQ(ierr);
821           assert(flid>=0);
822         }
823         /* copy in B_i matrix - column oriented */
824         data = &data_in[flid*bs];
825         for (kk = ii = 0; ii < bs ; ii++) {
826           for (jj = 0; jj < N ; jj++) {
827             PetscReal d = data[jj*data_stride + ii];
828             qqc[jj*Mdata + aggID*bs + ii] = d;
829           }
830         }
831 #if defined(OUT_AGGS)
832         if (llev==1) {
833           char str[] = "plot(%e,%e,'r*'), hold on,\n", col[] = "rgbkmc", sim[] = "*os+h>d<vx^";
834           PetscInt MM,pi,pj;
835           str[12] = col[(clid+17*mype)%6]; str[13] = sim[(clid+17*mype)%11];
836           MM = (PetscInt)(PetscSqrtReal((PetscReal)pM));
837           pj = gid1/MM; pi = gid1%MM;
838           fprintf(file,str,(double)pi,(double)pj);
839           /* fprintf(file,str,data[2*data_stride+1],-data[2*data_stride]); */
840         }
841 #endif
842         /* set fine IDs */
843         for (kk=0;kk<bs;kk++) fids[aggID*bs + kk] = flid_fgid[flid]*bs + kk;
844 
845         aggID++;
846       }
847 
848       /* pad with zeros */
849       for (ii = asz*bs; ii < Mdata ; ii++) {
850         for (jj = 0; jj < N ; jj++, kk++) {
851           qqc[jj*Mdata + ii] = .0;
852         }
853       }
854 
855       ndone += aggID;
856       /* QR */
857       ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
858       LAPACKgeqrf_(&Mdata, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO);
859       ierr = PetscFPTrapPop();CHKERRQ(ierr);
860       if (INFO != 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xGEQRF error");
861       /* get R - column oriented - output B_{i+1} */
862       {
863         PetscReal *data = &out_data[clid*nSAvec];
864         for (jj = 0; jj < nSAvec ; jj++) {
865           for (ii = 0; ii < nSAvec ; ii++) {
866             assert(data[jj*out_data_stride + ii] == 1.e300);
867             if (ii <= jj) data[jj*out_data_stride + ii] = PetscRealPart(qqc[jj*Mdata + ii]);
868             else data[jj*out_data_stride + ii] = 0.;
869           }
870         }
871       }
872 
873       /* get Q - row oriented */
874       LAPACKungqr_(&Mdata, &N, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO);
875       if (INFO != 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xORGQR error arg %d",-INFO);
876 
877       for (ii = 0 ; ii < M ; ii++) {
878         for (jj = 0 ; jj < N ; jj++) {
879           qqr[N*ii + jj] = qqc[jj*Mdata + ii];
880         }
881       }
882 
883       /* add diagonal block of P0 */
884       for (kk=0;kk<N;kk++) {
885         cids[kk] = N*cgid + kk; /* global col IDs in P0 */
886       }
887       ierr = MatSetValues(a_Prol,M,fids,N,cids,qqr,INSERT_VALUES);CHKERRQ(ierr);
888 
889       ierr = PetscFree(qqc);CHKERRQ(ierr);
890       ierr = PetscFree(qqr);CHKERRQ(ierr);
891       ierr = PetscFree(TAU);CHKERRQ(ierr);
892       ierr = PetscFree(WORK);CHKERRQ(ierr);
893       ierr = PetscFree(fids);CHKERRQ(ierr);
894       clid++;
895     } /* coarse agg */
896   } /* for all fine nodes */
897   ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
898   ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
899 
900 /* ierr = MPI_Allreduce(&ndone, &ii, 1, MPIU_INT, MPIU_SUM, wcomm); */
901 /* MatGetSize(a_Prol, &kk, &jj); */
902 /* ierr = MPI_Allreduce(&minsz, &jj, 1, MPIU_INT, MPIU_MIN, wcomm); */
903 /* PetscPrintf(wcomm," **** [%d]%s %d total done, %d nodes (%d local done), min agg. size = %d\n",mype,__FUNCT__,ii,kk/bs,ndone,jj); */
904 
905 #if defined(OUT_AGGS)
906   if (llev==1) fclose(file);
907 #endif
908   ierr = GAMGTableDestroy(&fgid_flid);CHKERRQ(ierr);
909 
910   PetscFunctionReturn(0);
911 }
912 
913 /* -------------------------------------------------------------------------- */
914 /*
915    PCGAMGgraph_AGG
916 
917   Input Parameter:
918    . pc - this
919    . Amat - matrix on this fine level
920   Output Parameter:
921    . a_Gmat -
922 */
923 #undef __FUNCT__
924 #define __FUNCT__ "PCGAMGgraph_AGG"
925 PetscErrorCode PCGAMGgraph_AGG(PC pc,
926                                 const Mat Amat,
927                                 Mat *a_Gmat)
928 {
929   PetscErrorCode ierr;
930   PC_MG          *mg = (PC_MG*)pc->data;
931   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
932   const PetscInt verbose = pc_gamg->verbose;
933   const PetscReal vfilter = pc_gamg->threshold;
934   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
935   PetscMPIInt    mype,npe;
936   Mat            Gmat;
937   MPI_Comm       wcomm = ((PetscObject)Amat)->comm;
938   PetscBool  /* set,flg , */symm;
939 
940   PetscFunctionBegin;
941 #if defined PETSC_USE_LOG
942   ierr = PetscLogEventBegin(PC_GAMGGgraph_AGG,0,0,0,0);CHKERRQ(ierr);
943 #endif
944   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
945   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
946 
947   /* ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr); || !(set && flg) -- this causes lot of symm calls */
948   symm = (PetscBool)(pc_gamg_agg->sym_graph); /* && !pc_gamg_agg->square_graph; */
949 
950   ierr  = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
951   ierr  = PCGAMGFilterGraph(&Gmat, vfilter, symm, verbose);CHKERRQ(ierr);
952 
953   *a_Gmat = Gmat;
954 
955 #if defined PETSC_USE_LOG
956   ierr = PetscLogEventEnd(PC_GAMGGgraph_AGG,0,0,0,0);CHKERRQ(ierr);
957 #endif
958   PetscFunctionReturn(0);
959 }
960 
961 /* -------------------------------------------------------------------------- */
962 /*
963    PCGAMGCoarsen_AGG
964 
965   Input Parameter:
966    . a_pc - this
967   Input/Output Parameter:
968    . a_Gmat1 - graph on this fine level - coarsening can change this (squares it)
969   Output Parameter:
970    . agg_lists - list of aggregates
971 */
972 #undef __FUNCT__
973 #define __FUNCT__ "PCGAMGCoarsen_AGG"
974 PetscErrorCode PCGAMGCoarsen_AGG(PC a_pc,
975                                   Mat *a_Gmat1,
976                                   PetscCoarsenData **agg_lists)
977 {
978   PetscErrorCode ierr;
979   PC_MG          *mg = (PC_MG*)a_pc->data;
980   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
981   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
982   Mat             mat,Gmat2, Gmat1 = *a_Gmat1; /* squared graph */
983   const PetscInt verbose = pc_gamg->verbose;
984   IS              perm;
985   PetscInt        Ii,nloc,bs,n,m;
986   PetscInt *permute;
987   PetscBool *bIndexSet;
988   MatCoarsen crs;
989   MPI_Comm        wcomm = ((PetscObject)Gmat1)->comm;
990   PetscMPIInt     mype,npe;
991 
992   PetscFunctionBegin;
993 #if defined PETSC_USE_LOG
994   ierr = PetscLogEventBegin(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
995 #endif
996   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
997   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
998   ierr = MatGetLocalSize(Gmat1, &n, &m);CHKERRQ(ierr);
999   ierr = MatGetBlockSize(Gmat1, &bs);CHKERRQ(ierr); assert(bs==1);
1000   nloc = n/bs;
1001 
1002   if (pc_gamg_agg->square_graph) {
1003     if (verbose > 1) {
1004       PetscPrintf(wcomm,"[%d]%s square graph\n",mype,__FUNCT__);
1005     }
1006     /* ierr = MatMatTransposeMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2); */
1007     ierr = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
1008     if (verbose > 2) {
1009       ierr = PetscPrintf(wcomm,"[%d]%s square graph done\n",mype,__FUNCT__);CHKERRQ(ierr);
1010       /* check for symetry */
1011       if (verbose > 4) {
1012 
1013       }
1014     }
1015   } else Gmat2 = Gmat1;
1016 
1017   /* get MIS aggs */
1018   /* randomize */
1019   ierr = PetscMalloc(nloc*sizeof(PetscInt), &permute);CHKERRQ(ierr);
1020   ierr = PetscMalloc(nloc*sizeof(PetscBool), &bIndexSet);CHKERRQ(ierr);
1021   for (Ii = 0; Ii < nloc ; Ii++) {
1022     bIndexSet[Ii] = PETSC_FALSE;
1023     permute[Ii] = Ii;
1024   }
1025   srand(1); /* make deterministic */
1026   for (Ii = 0; Ii < nloc ; Ii++) {
1027     PetscInt iSwapIndex = rand()%nloc;
1028     if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
1029       PetscInt iTemp = permute[iSwapIndex];
1030       permute[iSwapIndex] = permute[Ii];
1031       permute[Ii] = iTemp;
1032       bIndexSet[iSwapIndex] = PETSC_TRUE;
1033     }
1034   }
1035   ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
1036 
1037   if (verbose > 1) {
1038     PetscPrintf(wcomm,"[%d]%s coarsen graph\n",mype,__FUNCT__);
1039   }
1040 
1041   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_USE_POINTER, &perm);CHKERRQ(ierr);
1042 #if defined PETSC_GAMG_USE_LOG
1043   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
1044 #endif
1045   ierr = MatCoarsenCreate(wcomm, &crs);CHKERRQ(ierr);
1046   /* ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr); */
1047   ierr = MatCoarsenSetFromOptions(crs);CHKERRQ(ierr);
1048   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
1049   ierr = MatCoarsenSetAdjacency(crs, Gmat2);CHKERRQ(ierr);
1050   ierr = MatCoarsenSetVerbose(crs, pc_gamg->verbose);CHKERRQ(ierr);
1051   ierr = MatCoarsenSetStrictAggs(crs, PETSC_TRUE);CHKERRQ(ierr);
1052   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
1053   ierr = MatCoarsenGetData(crs, agg_lists);CHKERRQ(ierr); /* output */
1054   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
1055 
1056   ierr = ISDestroy(&perm);CHKERRQ(ierr);
1057   ierr = PetscFree(permute);CHKERRQ(ierr);
1058 #if defined PETSC_GAMG_USE_LOG
1059   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
1060 #endif
1061   if (verbose > 2) {
1062     PetscPrintf(wcomm,"[%d]%s coarsen graph done\n",mype,__FUNCT__);
1063   }
1064 
1065   /* smooth aggs */
1066   if (Gmat2 != Gmat1) {
1067     const PetscCoarsenData *llist = *agg_lists;
1068     ierr = smoothAggs(Gmat2, Gmat1, *agg_lists);CHKERRQ(ierr);
1069     ierr = MatDestroy(&Gmat1);CHKERRQ(ierr);
1070     *a_Gmat1 = Gmat2; /* output */
1071     ierr = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1072     if (mat) SETERRQ(wcomm,PETSC_ERR_ARG_WRONG, "Auxilary matrix with squared graph????");
1073   } else {
1074     const PetscCoarsenData *llist = *agg_lists;
1075     /* see if we have a matrix that takes precedence (returned from MatCoarsenAppply) */
1076     ierr = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1077     if (mat) {
1078       ierr = MatDestroy(&Gmat1);CHKERRQ(ierr);
1079       *a_Gmat1 = mat; /* output */
1080     }
1081   }
1082 #if defined PETSC_USE_LOG
1083   ierr = PetscLogEventEnd(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
1084 #endif
1085   if (verbose > 2) {
1086     PetscPrintf(wcomm,"[%d]%s PCGAMGCoarsen_AGG done\n",mype,__FUNCT__);
1087   }
1088 
1089   PetscFunctionReturn(0);
1090 }
1091 
1092 /* -------------------------------------------------------------------------- */
1093 /*
1094  PCGAMGProlongator_AGG
1095 
1096  Input Parameter:
1097  . pc - this
1098  . Amat - matrix on this fine level
1099  . Graph - used to get ghost data for nodes in
1100  . agg_lists - list of aggregates
1101  Output Parameter:
1102  . a_P_out - prolongation operator to the next level
1103  */
1104 #undef __FUNCT__
1105 #define __FUNCT__ "PCGAMGProlongator_AGG"
1106 PetscErrorCode PCGAMGProlongator_AGG(PC pc,
1107                                       const Mat Amat,
1108                                       const Mat Gmat,
1109                                       PetscCoarsenData *agg_lists,
1110                                       Mat *a_P_out)
1111 {
1112   PC_MG          *mg = (PC_MG*)pc->data;
1113   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1114   const PetscInt verbose = pc_gamg->verbose;
1115   const PetscInt data_cols = pc_gamg->data_cell_cols;
1116   PetscErrorCode ierr;
1117   PetscInt       Istart,Iend,nloc,ii,jj,kk,my0,nLocalSelected,bs;
1118   Mat            Prol;
1119   PetscMPIInt    mype, npe;
1120   MPI_Comm       wcomm = ((PetscObject)Amat)->comm;
1121   const PetscInt col_bs = data_cols;
1122   PetscReal      *data_w_ghost;
1123   PetscInt       myCrs0, nbnodes=0, *flid_fgid;
1124 
1125   PetscFunctionBegin;
1126 #if defined PETSC_USE_LOG
1127   ierr = PetscLogEventBegin(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1128 #endif
1129   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
1130   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
1131   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1132   ierr  = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
1133   nloc = (Iend-Istart)/bs; my0 = Istart/bs; assert((Iend-Istart)%bs==0);
1134 
1135   /* get 'nLocalSelected' */
1136   for (ii=0, nLocalSelected = 0 ; ii < nloc ; ii++) {
1137     PetscBool ise;
1138     /* filter out singletons 0 or 1? */
1139     ierr = PetscCDEmptyAt(agg_lists, ii, &ise);CHKERRQ(ierr);
1140     if (!ise) nLocalSelected++;
1141   }
1142 
1143   /* create prolongator, create P matrix */
1144   ierr = MatCreate(wcomm, &Prol);CHKERRQ(ierr);
1145   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*col_bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
1146   ierr = MatSetBlockSizes(Prol, bs, col_bs);CHKERRQ(ierr);
1147   ierr = MatSetType(Prol, MATAIJ);CHKERRQ(ierr);
1148   ierr = MatSeqAIJSetPreallocation(Prol, data_cols, PETSC_NULL);CHKERRQ(ierr);
1149   ierr = MatMPIAIJSetPreallocation(Prol,data_cols, PETSC_NULL,data_cols, PETSC_NULL);CHKERRQ(ierr);
1150   /* nloc*bs, nLocalSelected*col_bs, */
1151   /* PETSC_DETERMINE, PETSC_DETERMINE, */
1152   /* data_cols, PETSC_NULL, data_cols, PETSC_NULL, */
1153   /* &Prol); */
1154 
1155   /* can get all points "removed" */
1156   ierr =  MatGetSize(Prol, &kk, &ii);CHKERRQ(ierr);
1157   if (ii==0) {
1158     if (verbose > 0) {
1159       PetscPrintf(wcomm,"[%d]%s no selected points on coarse grid\n",mype,__FUNCT__);
1160     }
1161     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
1162     *a_P_out = PETSC_NULL;  /* out */
1163     PetscFunctionReturn(0);
1164   }
1165   if (verbose > 0) {
1166     PetscPrintf(wcomm,"\t\t[%d]%s New grid %d nodes\n",mype,__FUNCT__,ii/col_bs);
1167   }
1168   ierr = MatGetOwnershipRangeColumn(Prol, &myCrs0, &kk);CHKERRQ(ierr);
1169 
1170   assert((kk-myCrs0)%col_bs==0);
1171   myCrs0 = myCrs0/col_bs;
1172   assert((kk/col_bs-myCrs0)==nLocalSelected);
1173 
1174   /* create global vector of data in 'data_w_ghost' */
1175 #if defined PETSC_GAMG_USE_LOG
1176   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1177 #endif
1178   if (npe > 1) { /*  */
1179     PetscReal *tmp_gdata,*tmp_ldata,*tp2;
1180     ierr = PetscMalloc(nloc*sizeof(PetscReal), &tmp_ldata);CHKERRQ(ierr);
1181     for (jj = 0 ; jj < data_cols ; jj++) {
1182       for (kk = 0 ; kk < bs ; kk++) {
1183         PetscInt ii,stride;
1184         const PetscReal *tp = pc_gamg->data + jj*bs*nloc + kk;
1185         for (ii = 0 ; ii < nloc ; ii++, tp += bs) {
1186           tmp_ldata[ii] = *tp;
1187         }
1188         ierr = PCGAMGGetDataWithGhosts(Gmat, 1, tmp_ldata, &stride, &tmp_gdata);CHKERRQ(ierr);
1189 
1190         if (jj==0 && kk==0) { /* now I know how many todal nodes - allocate */
1191           ierr = PetscMalloc(stride*bs*data_cols*sizeof(PetscReal), &data_w_ghost);CHKERRQ(ierr);
1192           nbnodes = bs*stride;
1193         }
1194         tp2 = data_w_ghost + jj*bs*stride + kk;
1195         for (ii = 0 ; ii < stride ; ii++, tp2 += bs) {
1196           *tp2 = tmp_gdata[ii];
1197         }
1198         ierr = PetscFree(tmp_gdata);CHKERRQ(ierr);
1199       }
1200     }
1201     ierr = PetscFree(tmp_ldata);CHKERRQ(ierr);
1202   } else {
1203     nbnodes = bs*nloc;
1204     data_w_ghost = (PetscReal*)pc_gamg->data;
1205   }
1206 
1207   /* get P0 */
1208   if (npe > 1) {
1209     PetscReal *fid_glid_loc,*fiddata;
1210     PetscInt stride;
1211 
1212     ierr = PetscMalloc(nloc*sizeof(PetscReal), &fid_glid_loc);CHKERRQ(ierr);
1213     for (kk=0;kk<nloc;kk++) fid_glid_loc[kk] = (PetscReal)(my0+kk);
1214     ierr = PCGAMGGetDataWithGhosts(Gmat, 1, fid_glid_loc, &stride, &fiddata);CHKERRQ(ierr);
1215     ierr = PetscMalloc(stride*sizeof(PetscInt), &flid_fgid);CHKERRQ(ierr);
1216     for (kk=0;kk<stride;kk++) flid_fgid[kk] = (PetscInt)fiddata[kk];
1217     ierr = PetscFree(fiddata);CHKERRQ(ierr);
1218 
1219     assert(stride==nbnodes/bs);
1220     ierr = PetscFree(fid_glid_loc);CHKERRQ(ierr);
1221   } else {
1222     ierr = PetscMalloc(nloc*sizeof(PetscInt), &flid_fgid);CHKERRQ(ierr);
1223     for (kk=0;kk<nloc;kk++) flid_fgid[kk] = my0 + kk;
1224   }
1225 #if defined PETSC_GAMG_USE_LOG
1226   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1227   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1228 #endif
1229   {
1230     PetscReal *data_out = PETSC_NULL;
1231     ierr = formProl0(agg_lists, bs, data_cols, myCrs0, nbnodes,data_w_ghost, flid_fgid, &data_out, Prol);CHKERRQ(ierr);
1232     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1233     pc_gamg->data = data_out;
1234     pc_gamg->data_cell_rows = data_cols;
1235     pc_gamg->data_sz = data_cols*data_cols*nLocalSelected;
1236   }
1237 #if defined PETSC_GAMG_USE_LOG
1238   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1239 #endif
1240   if (npe > 1) ierr = PetscFree(data_w_ghost);CHKERRQ(ierr);
1241   ierr = PetscFree(flid_fgid);CHKERRQ(ierr);
1242 
1243   *a_P_out = Prol;  /* out */
1244 #if defined PETSC_USE_LOG
1245   ierr = PetscLogEventEnd(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1246 #endif
1247   PetscFunctionReturn(0);
1248 }
1249 
1250 /* -------------------------------------------------------------------------- */
1251 /*
1252    PCGAMGOptprol_AGG
1253 
1254   Input Parameter:
1255    . pc - this
1256    . Amat - matrix on this fine level
1257  In/Output Parameter:
1258    . a_P_out - prolongation operator to the next level
1259 */
1260 #undef __FUNCT__
1261 #define __FUNCT__ "PCGAMGOptprol_AGG"
1262 PetscErrorCode PCGAMGOptprol_AGG(PC pc,
1263                                   const Mat Amat,
1264                                   Mat *a_P)
1265 {
1266   PetscErrorCode ierr;
1267   PC_MG          *mg = (PC_MG*)pc->data;
1268   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1269   const PetscInt verbose = pc_gamg->verbose;
1270   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
1271   PetscInt       jj;
1272   PetscMPIInt    mype,npe;
1273   Mat            Prol = *a_P;
1274   MPI_Comm       wcomm = ((PetscObject)Amat)->comm;
1275 
1276   PetscFunctionBegin;
1277 #if defined PETSC_USE_LOG
1278   ierr = PetscLogEventBegin(PC_GAMGOptprol_AGG,0,0,0,0);CHKERRQ(ierr);
1279 #endif
1280   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
1281   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
1282 
1283   /* smooth P0 */
1284   for (jj = 0 ; jj < pc_gamg_agg->nsmooths ; jj++) {
1285     Mat tMat;
1286     Vec diag;
1287     PetscReal alpha, emax, emin;
1288 #if defined PETSC_GAMG_USE_LOG
1289     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1290 #endif
1291     if (jj == 0) {
1292       KSP eksp;
1293       Vec bb, xx;
1294       PC pc;
1295       ierr = MatGetVecs(Amat, &bb, 0);CHKERRQ(ierr);
1296       ierr = MatGetVecs(Amat, &xx, 0);CHKERRQ(ierr);
1297       {
1298         PetscRandom    rctx;
1299         ierr = PetscRandomCreate(wcomm,&rctx);CHKERRQ(ierr);
1300         ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
1301         ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
1302         ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
1303       }
1304 
1305       /* zeroing out BC rows -- needed for crazy matrices */
1306       {
1307         PetscInt Istart,Iend,ncols,jj,Ii;
1308         PetscScalar zero = 0.0;
1309         ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1310         for (Ii = Istart, jj = 0 ; Ii < Iend ; Ii++, jj++) {
1311           ierr = MatGetRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1312           if (ncols <= 1) {
1313             ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
1314           }
1315           ierr = MatRestoreRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1316         }
1317         ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
1318         ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
1319       }
1320 
1321       ierr = KSPCreate(wcomm,&eksp);CHKERRQ(ierr);
1322       ierr = KSPSetTolerances(eksp,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,10);CHKERRQ(ierr);
1323       ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
1324       ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
1325       ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
1326 
1327       ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
1328       ierr = KSPSetOperators(eksp, Amat, Amat, SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1329       ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
1330 
1331       ierr = KSPGetPC(eksp, &pc);CHKERRQ(ierr);
1332       ierr = PCSetType(pc, PCJACOBI);CHKERRQ(ierr);  /* smoother in smoothed agg. */
1333 
1334       /* solve - keep stuff out of logging */
1335       ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
1336       ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
1337       ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
1338       ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
1339       ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
1340 
1341       ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
1342       if (verbose > 0) {
1343         PetscPrintf(wcomm,"\t\t\t%s smooth P0: max eigen=%e min=%e PC=%s\n",
1344                     __FUNCT__,emax,emin,PCJACOBI);
1345       }
1346       ierr = VecDestroy(&xx);CHKERRQ(ierr);
1347       ierr = VecDestroy(&bb);CHKERRQ(ierr);
1348       ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
1349 
1350       if (pc_gamg->emax_id == -1) {
1351         ierr = PetscObjectComposedDataRegister(&pc_gamg->emax_id);CHKERRQ(ierr);
1352         assert(pc_gamg->emax_id != -1);
1353       }
1354       ierr = PetscObjectComposedDataSetScalar((PetscObject)Amat, pc_gamg->emax_id, emax);CHKERRQ(ierr);
1355     }
1356 
1357     /* smooth P1 := (I - omega/lam D^{-1}A)P0 */
1358     ierr = MatMatMult(Amat, Prol, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &tMat);CHKERRQ(ierr);
1359     ierr = MatGetVecs(Amat, &diag, 0);CHKERRQ(ierr);
1360     ierr = MatGetDiagonal(Amat, diag);CHKERRQ(ierr); /* effectively PCJACOBI */
1361     ierr = VecReciprocal(diag);CHKERRQ(ierr);
1362     ierr = MatDiagonalScale(tMat, diag, 0);CHKERRQ(ierr);
1363     ierr = VecDestroy(&diag);CHKERRQ(ierr);
1364     alpha = -1.4/emax;
1365     ierr = MatAYPX(tMat, alpha, Prol, SUBSET_NONZERO_PATTERN);CHKERRQ(ierr);
1366     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
1367     Prol = tMat;
1368 #if defined PETSC_GAMG_USE_LOG
1369     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1370 #endif
1371   }
1372 #if defined PETSC_USE_LOG
1373   ierr = PetscLogEventEnd(PC_GAMGOptprol_AGG,0,0,0,0);CHKERRQ(ierr);
1374 #endif
1375   *a_P = Prol;
1376 
1377   PetscFunctionReturn(0);
1378 }
1379 
1380 /* -------------------------------------------------------------------------- */
1381 /*
1382    PCGAMGKKTProl_AGG
1383 
1384   Input Parameter:
1385    . pc - this
1386    . Prol11 - matrix on this fine level
1387    . A21 - matrix on this fine level
1388  In/Output Parameter:
1389    . a_P22 - prolongation operator to the next level
1390 */
1391 #undef __FUNCT__
1392 #define __FUNCT__ "PCGAMGKKTProl_AGG"
1393 PetscErrorCode PCGAMGKKTProl_AGG(PC pc,
1394                                   const Mat Prol11,
1395                                   const Mat A21,
1396                                   Mat *a_P22)
1397 {
1398   PetscErrorCode ierr;
1399   PC_MG          *mg = (PC_MG*)pc->data;
1400   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1401   const PetscInt verbose = pc_gamg->verbose;
1402   /* PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;  */
1403   PetscMPIInt    mype,npe;
1404   Mat            Prol22,Tmat,Gmat;
1405   MPI_Comm       wcomm = ((PetscObject)pc)->comm;
1406   PetscCoarsenData *agg_lists;
1407 
1408   PetscFunctionBegin;
1409 #if defined PETSC_USE_LOG
1410   ierr = PetscLogEventBegin(PC_GAMGKKTProl_AGG,0,0,0,0);CHKERRQ(ierr);
1411 #endif
1412   ierr = MPI_Comm_rank(wcomm, &mype);CHKERRQ(ierr);
1413   ierr = MPI_Comm_size(wcomm, &npe);CHKERRQ(ierr);
1414 
1415   /* form C graph */
1416   ierr = MatMatMult(A21, Prol11, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Tmat);CHKERRQ(ierr);
1417   ierr = MatMatTransposeMult(Tmat, Tmat, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat);CHKERRQ(ierr);
1418   ierr = MatDestroy(&Tmat);CHKERRQ(ierr);
1419   ierr  = PCGAMGFilterGraph(&Gmat, 0.0, PETSC_FALSE, verbose);CHKERRQ(ierr);
1420 
1421   /* coarsen constraints */
1422   {
1423     MatCoarsen crs;
1424     ierr = MatCoarsenCreate(wcomm, &crs);CHKERRQ(ierr);
1425     ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr);
1426     ierr = MatCoarsenSetAdjacency(crs, Gmat);CHKERRQ(ierr);
1427     ierr = MatCoarsenSetVerbose(crs, verbose);CHKERRQ(ierr);
1428     ierr = MatCoarsenSetStrictAggs(crs, PETSC_TRUE);CHKERRQ(ierr);
1429     ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
1430     ierr = MatCoarsenGetData(crs, &agg_lists);CHKERRQ(ierr);
1431     ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
1432   }
1433 
1434   /* form simple prolongation 'Prol22' */
1435   {
1436     PetscInt ii,mm,clid,my0,nloc,nLocalSelected;
1437     PetscScalar val = 1.0;
1438     /* get 'nLocalSelected' */
1439     ierr = MatGetLocalSize(Gmat, &nloc, &ii);CHKERRQ(ierr);
1440     for (ii=0, nLocalSelected = 0 ; ii < nloc ; ii++) {
1441       PetscBool ise;
1442       /* filter out singletons 0 or 1? */
1443       ierr = PetscCDEmptyAt(agg_lists, ii, &ise);CHKERRQ(ierr);
1444       if (!ise) nLocalSelected++;
1445     }
1446 
1447     ierr = MatCreate(wcomm,&Prol22);CHKERRQ(ierr);
1448     ierr = MatSetSizes(Prol22,nloc, nLocalSelected,PETSC_DETERMINE, PETSC_DETERMINE);CHKERRQ(ierr);
1449     ierr = MatSetType(Prol22, MATAIJ);CHKERRQ(ierr);
1450     ierr = MatSeqAIJSetPreallocation(Prol22,1,PETSC_NULL);CHKERRQ(ierr);
1451     ierr = MatMPIAIJSetPreallocation(Prol22,1,PETSC_NULL,1,PETSC_NULL);CHKERRQ(ierr);
1452     /* ierr = MatCreateAIJ(wcomm, */
1453     /*                      nloc, nLocalSelected, */
1454     /*                      PETSC_DETERMINE, PETSC_DETERMINE, */
1455     /*                      1, PETSC_NULL, 1, PETSC_NULL, */
1456     /*                      &Prol22); */
1457 
1458     ierr = MatGetOwnershipRange(Prol22, &my0, &ii);CHKERRQ(ierr);
1459     nloc = ii - my0;
1460 
1461     /* make aggregates */
1462     for (mm = clid = 0 ; mm < nloc ; mm++) {
1463       ierr = PetscCDSizeAt(agg_lists, mm, &ii);CHKERRQ(ierr);
1464       if (ii > 0) {
1465         PetscInt asz=ii,cgid=my0+clid,rids[1000];
1466         PetscCDPos pos;
1467         if (asz>1000)SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Very large aggregate: %d",asz);
1468         ii = 0;
1469         ierr = PetscCDGetHeadPos(agg_lists,mm,&pos);CHKERRQ(ierr);
1470         while (pos) {
1471           PetscInt gid1;
1472           ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
1473           ierr = PetscCDGetNextPos(agg_lists,mm,&pos);CHKERRQ(ierr);
1474 
1475           rids[ii++] = gid1;
1476         }
1477         assert(ii==asz);
1478         /* add diagonal block of P0 */
1479         ierr = MatSetValues(Prol22,asz,rids,1,&cgid,&val,INSERT_VALUES);CHKERRQ(ierr);
1480 
1481         clid++;
1482       } /* coarse agg */
1483     } /* for all fine nodes */
1484     ierr = MatAssemblyBegin(Prol22,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1485     ierr = MatAssemblyEnd(Prol22,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1486   }
1487 
1488   /* clean up */
1489   ierr = MatDestroy(&Gmat);CHKERRQ(ierr);
1490   ierr = PetscCDDestroy(agg_lists);CHKERRQ(ierr);
1491 #if defined PETSC_USE_LOG
1492   ierr = PetscLogEventEnd(PC_GAMGKKTProl_AGG,0,0,0,0);CHKERRQ(ierr);
1493 #endif
1494   *a_P22 = Prol22;
1495 
1496   PetscFunctionReturn(0);
1497 }
1498 
1499 /* -------------------------------------------------------------------------- */
1500 /*
1501    PCCreateGAMG_AGG
1502 
1503   Input Parameter:
1504    . pc -
1505 */
1506 #undef __FUNCT__
1507 #define __FUNCT__ "PCCreateGAMG_AGG"
1508 PetscErrorCode  PCCreateGAMG_AGG(PC pc)
1509 {
1510   PetscErrorCode  ierr;
1511   PC_MG           *mg = (PC_MG*)pc->data;
1512   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
1513   PC_GAMG_AGG      *pc_gamg_agg;
1514 
1515   PetscFunctionBegin;
1516   if (pc_gamg->subctx) {
1517     /* call base class */
1518     ierr = PCDestroy_GAMG(pc);CHKERRQ(ierr);
1519   }
1520 
1521   /* create sub context for SA */
1522   ierr = PetscNewLog(pc, PC_GAMG_AGG, &pc_gamg_agg);CHKERRQ(ierr);
1523   pc_gamg->subctx = pc_gamg_agg;
1524 
1525   pc->ops->setfromoptions = PCSetFromOptions_GAMG_AGG;
1526   pc->ops->destroy        = PCDestroy_AGG;
1527   /* reset does not do anything; setup not virtual */
1528 
1529   /* set internal function pointers */
1530   pc_gamg->graph = PCGAMGgraph_AGG;
1531   pc_gamg->coarsen = PCGAMGCoarsen_AGG;
1532   pc_gamg->prolongator = PCGAMGProlongator_AGG;
1533   pc_gamg->optprol = PCGAMGOptprol_AGG;
1534   pc_gamg->formkktprol = PCGAMGKKTProl_AGG;
1535 
1536   pc_gamg->createdefaultdata = PCSetData_AGG;
1537 
1538   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCSetCoordinates_C","PCSetCoordinates_AGG",PCSetCoordinates_AGG);CHKERRQ(ierr);
1539   PetscFunctionReturn(0);
1540 }
1541