xref: /petsc/src/ksp/pc/impls/gamg/agg.c (revision bebe2cf65d55febe21a5af8db2bd2e168caaa2e7)
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   PetscInt 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, PetscInt n)
120 {
121   PetscErrorCode ierr;
122 
123   PetscFunctionBegin;
124   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
125   ierr = PetscTryMethod(pc,"PCGAMGSetSquareGraph_C",(PC,PetscInt),(pc,n));CHKERRQ(ierr);
126   PetscFunctionReturn(0);
127 }
128 
129 #undef __FUNCT__
130 #define __FUNCT__ "PCGAMGSetSquareGraph_GAMG"
131 PetscErrorCode PCGAMGSetSquareGraph_GAMG(PC pc, PetscInt 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(PetscOptions *PetscOptionsObject,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 
158   PetscFunctionBegin;
159   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG-AGG options");CHKERRQ(ierr);
160   {
161     /* -pc_gamg_agg_nsmooths */
162     pc_gamg_agg->nsmooths = 1;
163 
164     ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths","smoothing steps for smoothed aggregation, usually 1","PCGAMGSetNSmooths",pc_gamg_agg->nsmooths,&pc_gamg_agg->nsmooths,NULL);CHKERRQ(ierr);
165 
166     /* -pc_gamg_sym_graph */
167     pc_gamg_agg->sym_graph = PETSC_FALSE;
168 
169     ierr = PetscOptionsBool("-pc_gamg_sym_graph","Set for asymmetric matrices","PCGAMGSetSymGraph",pc_gamg_agg->sym_graph,&pc_gamg_agg->sym_graph,NULL);CHKERRQ(ierr);
170 
171     /* -pc_gamg_square_graph */
172     pc_gamg_agg->square_graph = 1;
173 
174     ierr = PetscOptionsInt("-pc_gamg_square_graph","Number of levels to square graph for faster coarsening and lower coarse grid complexity","PCGAMGSetSquareGraph",pc_gamg_agg->square_graph,&pc_gamg_agg->square_graph,NULL);CHKERRQ(ierr);
175   }
176   ierr = PetscOptionsTail();CHKERRQ(ierr);
177   PetscFunctionReturn(0);
178 }
179 
180 /* -------------------------------------------------------------------------- */
181 /*
182    PCDestroy_AGG
183 
184   Input Parameter:
185    . pc -
186 */
187 #undef __FUNCT__
188 #define __FUNCT__ "PCDestroy_GAMG_AGG"
189 PetscErrorCode PCDestroy_GAMG_AGG(PC pc)
190 {
191   PetscErrorCode ierr;
192   PC_MG          *mg          = (PC_MG*)pc->data;
193   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
194 
195   PetscFunctionBegin;
196   ierr = PetscFree(pc_gamg->subctx);CHKERRQ(ierr);
197   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",NULL);CHKERRQ(ierr);
198   PetscFunctionReturn(0);
199 }
200 
201 /* -------------------------------------------------------------------------- */
202 /*
203    PCSetCoordinates_AGG
204      - collective
205 
206    Input Parameter:
207    . pc - the preconditioner context
208    . ndm - dimesion of data (used for dof/vertex for Stokes)
209    . a_nloc - number of vertices local
210    . coords - [a_nloc][ndm] - interleaved coordinate data: {x_0, y_0, z_0, x_1, y_1, ...}
211 */
212 
213 #undef __FUNCT__
214 #define __FUNCT__ "PCSetCoordinates_AGG"
215 static PetscErrorCode PCSetCoordinates_AGG(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
216 {
217   PC_MG          *mg      = (PC_MG*)pc->data;
218   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
219   PetscErrorCode ierr;
220   PetscInt       arrsz,kk,ii,jj,nloc,ndatarows,ndf;
221   Mat            mat = pc->pmat;
222 
223   PetscFunctionBegin;
224   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
225   PetscValidHeaderSpecific(mat,MAT_CLASSID,1);
226   nloc = a_nloc;
227 
228   /* SA: null space vectors */
229   ierr = MatGetBlockSize(mat, &ndf);CHKERRQ(ierr); /* this does not work for Stokes */
230   if (coords && ndf==1) pc_gamg->data_cell_cols = 1; /* scalar w/ coords and SA (not needed) */
231   else if (coords) {
232     if (ndm > ndf) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"degrees of motion %d > block size %d",ndm,ndf);
233     pc_gamg->data_cell_cols = (ndm==2 ? 3 : 6); /* displacement elasticity */
234     if (ndm != ndf) {
235       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);
236     }
237   } else pc_gamg->data_cell_cols = ndf; /* no data, force SA with constant null space vectors */
238   pc_gamg->data_cell_rows = ndatarows = ndf;
239   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);
240   arrsz = nloc*pc_gamg->data_cell_rows*pc_gamg->data_cell_cols;
241 
242   /* create data - syntactic sugar that should be refactored at some point */
243   if (pc_gamg->data==0 || (pc_gamg->data_sz != arrsz)) {
244     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
245     ierr = PetscMalloc1(arrsz+1, &pc_gamg->data);CHKERRQ(ierr);
246   }
247   /* copy data in - column oriented */
248   for (kk=0; kk<nloc; kk++) {
249     const PetscInt M     = nloc*pc_gamg->data_cell_rows; /* stride into data */
250     PetscReal      *data = &pc_gamg->data[kk*ndatarows]; /* start of cell */
251     if (pc_gamg->data_cell_cols==1) *data = 1.0;
252     else {
253       /* translational modes */
254       for (ii=0;ii<ndatarows;ii++) {
255         for (jj=0;jj<ndatarows;jj++) {
256           if (ii==jj)data[ii*M + jj] = 1.0;
257           else data[ii*M + jj] = 0.0;
258         }
259       }
260 
261       /* rotational modes */
262       if (coords) {
263         if (ndm == 2) {
264           data   += 2*M;
265           data[0] = -coords[2*kk+1];
266           data[1] =  coords[2*kk];
267         } else {
268           data   += 3*M;
269           data[0] = 0.0;             data[M+0] =  coords[3*kk+2]; data[2*M+0] = -coords[3*kk+1];
270           data[1] = -coords[3*kk+2]; data[M+1] = 0.0;             data[2*M+1] =  coords[3*kk];
271           data[2] =  coords[3*kk+1]; data[M+2] = -coords[3*kk];   data[2*M+2] = 0.0;
272         }
273       }
274     }
275   }
276 
277   pc_gamg->data_sz = arrsz;
278   PetscFunctionReturn(0);
279 }
280 
281 typedef PetscInt NState;
282 static const NState NOT_DONE=-2;
283 static const NState DELETED =-1;
284 static const NState REMOVED =-3;
285 #define IS_SELECTED(s) (s!=DELETED && s!=NOT_DONE && s!=REMOVED)
286 
287 /* -------------------------------------------------------------------------- */
288 /*
289    smoothAggs - greedy grab of with G1 (unsquared graph) -- AIJ specific
290      - AGG-MG specific: clears singletons out of 'selected_2'
291 
292    Input Parameter:
293    . Gmat_2 - glabal matrix of graph (data not defined)   base (squared) graph
294    . Gmat_1 - base graph to grab with                 base graph
295    Input/Output Parameter:
296    . aggs_2 - linked list of aggs with gids)
297 */
298 #undef __FUNCT__
299 #define __FUNCT__ "smoothAggs"
300 static PetscErrorCode smoothAggs(Mat Gmat_2, Mat Gmat_1,PetscCoarsenData *aggs_2)
301 {
302   PetscErrorCode ierr;
303   PetscBool      isMPI;
304   Mat_SeqAIJ     *matA_1, *matB_1=0, *matA_2, *matB_2=0;
305   MPI_Comm       comm;
306   PetscInt       lid,*ii,*idx,ix,Iend,my0,kk,n,j;
307   Mat_MPIAIJ     *mpimat_2 = 0, *mpimat_1=0;
308   const PetscInt nloc      = Gmat_2->rmap->n;
309   PetscScalar    *cpcol_1_state,*cpcol_2_state,*cpcol_2_par_orig,*lid_parent_gid;
310   PetscInt       *lid_cprowID_1;
311   NState         *lid_state;
312   Vec            ghost_par_orig2;
313 
314   PetscFunctionBegin;
315   ierr = PetscObjectGetComm((PetscObject)Gmat_2,&comm);CHKERRQ(ierr);
316   ierr = MatGetOwnershipRange(Gmat_1,&my0,&Iend);CHKERRQ(ierr);
317 
318   if (PETSC_FALSE) {
319     PetscViewer viewer; char fname[32]; static int llev=0;
320     sprintf(fname,"Gmat2_%d.m",llev++);
321     PetscViewerASCIIOpen(comm,fname,&viewer);
322     ierr = PetscViewerSetFormat(viewer, PETSC_VIEWER_ASCII_MATLAB);CHKERRQ(ierr);
323     ierr = MatView(Gmat_2, viewer);CHKERRQ(ierr);
324     ierr = PetscViewerDestroy(&viewer);
325   }
326 
327   /* get submatrices */
328   ierr = PetscObjectTypeCompare((PetscObject)Gmat_1, MATMPIAIJ, &isMPI);CHKERRQ(ierr);
329   if (isMPI) {
330     /* grab matrix objects */
331     mpimat_2 = (Mat_MPIAIJ*)Gmat_2->data;
332     mpimat_1 = (Mat_MPIAIJ*)Gmat_1->data;
333     matA_1   = (Mat_SeqAIJ*)mpimat_1->A->data;
334     matB_1   = (Mat_SeqAIJ*)mpimat_1->B->data;
335     matA_2   = (Mat_SeqAIJ*)mpimat_2->A->data;
336     matB_2   = (Mat_SeqAIJ*)mpimat_2->B->data;
337 
338     /* force compressed row storage for B matrix in AuxMat */
339     ierr = MatCheckCompressedRow(mpimat_1->B,matB_1->nonzerorowcnt,&matB_1->compressedrow,matB_1->i,Gmat_1->rmap->n,-1.0);CHKERRQ(ierr);
340 
341     ierr = PetscMalloc1(nloc, &lid_cprowID_1);CHKERRQ(ierr);
342     for (lid = 0; lid < nloc; lid++) lid_cprowID_1[lid] = -1;
343     for (ix=0; ix<matB_1->compressedrow.nrows; ix++) {
344       PetscInt lid = matB_1->compressedrow.rindex[ix];
345       lid_cprowID_1[lid] = ix;
346     }
347   } else {
348     matA_1        = (Mat_SeqAIJ*)Gmat_1->data;
349     matA_2        = (Mat_SeqAIJ*)Gmat_2->data;
350     lid_cprowID_1 = NULL;
351   }
352   if (nloc>0) {
353     if (!(matA_1 && !matA_1->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matA_1 && !matA_1->compressedrow.use)");
354     if (!(matB_1==0 || matB_1->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matB_1==0 || matB_1->compressedrow.use)");
355     if (!(matA_2 && !matA_2->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matA_2 && !matA_2->compressedrow.use)");
356     if (!(matB_2==0 || matB_2->compressedrow.use)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"!(matB_2==0 || matB_2->compressedrow.use)");
357   }
358   /* get state of locals and selected gid for deleted */
359   ierr = PetscMalloc2(nloc, &lid_state,nloc, &lid_parent_gid);CHKERRQ(ierr);
360   for (lid = 0; lid < nloc; lid++) {
361     lid_parent_gid[lid] = -1.0;
362     lid_state[lid]      = DELETED;
363   }
364 
365   /* set lid_state */
366   for (lid = 0; lid < nloc; lid++) {
367     PetscCDPos pos;
368     ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
369     if (pos) {
370       PetscInt gid1;
371 
372       ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
373       if (gid1 != lid+my0) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"gid1 %D != lid %D + my0 %D",gid1,lid,my0);
374       lid_state[lid] = gid1;
375     }
376   }
377 
378   /* map local to selected local, DELETED means a ghost owns it */
379   for (lid=kk=0; lid<nloc; lid++) {
380     NState state = lid_state[lid];
381     if (IS_SELECTED(state)) {
382       PetscCDPos pos;
383       ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
384       while (pos) {
385         PetscInt gid1;
386         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
387         ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
388 
389         if (gid1 >= my0 && gid1 < Iend) lid_parent_gid[gid1-my0] = (PetscScalar)(lid + my0);
390       }
391     }
392   }
393   /* get 'cpcol_1/2_state' & cpcol_2_par_orig - uses mpimat_1/2->lvec for temp space */
394   if (isMPI) {
395     Vec tempVec;
396     /* get 'cpcol_1_state' */
397     ierr = MatCreateVecs(Gmat_1, &tempVec, 0);CHKERRQ(ierr);
398     for (kk=0,j=my0; kk<nloc; kk++,j++) {
399       PetscScalar v = (PetscScalar)lid_state[kk];
400       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
401     }
402     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
403     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
404     ierr = VecScatterBegin(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
405     ierr = VecScatterEnd(mpimat_1->Mvctx,tempVec, mpimat_1->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
406     ierr = VecGetArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
407     /* get 'cpcol_2_state' */
408     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
409     ierr =   VecScatterEnd(mpimat_2->Mvctx,tempVec, mpimat_2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
410     ierr = VecGetArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
411     /* get 'cpcol_2_par_orig' */
412     for (kk=0,j=my0; kk<nloc; kk++,j++) {
413       PetscScalar v = (PetscScalar)lid_parent_gid[kk];
414       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
415     }
416     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
417     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
418     ierr = VecDuplicate(mpimat_2->lvec, &ghost_par_orig2);CHKERRQ(ierr);
419     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
420     ierr = VecScatterEnd(mpimat_2->Mvctx,tempVec, ghost_par_orig2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
421     ierr = VecGetArray(ghost_par_orig2, &cpcol_2_par_orig);CHKERRQ(ierr);
422 
423     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
424   } /* ismpi */
425 
426   /* doit */
427   for (lid=0; lid<nloc; lid++) {
428     NState state = lid_state[lid];
429     if (IS_SELECTED(state)) {
430       /* steal locals */
431       ii  = matA_1->i; n = ii[lid+1] - ii[lid];
432       idx = matA_1->j + ii[lid];
433       for (j=0; j<n; j++) {
434         PetscInt lidj   = idx[j], sgid;
435         NState   statej = lid_state[lidj];
436         if (statej==DELETED && (sgid=(PetscInt)PetscRealPart(lid_parent_gid[lidj])) != lid+my0) { /* steal local */
437           lid_parent_gid[lidj] = (PetscScalar)(lid+my0); /* send this if sgid is not local */
438           if (sgid >= my0 && sgid < Iend) {       /* I'm stealing this local from a local sgid */
439             PetscInt   hav=0,slid=sgid-my0,gidj=lidj+my0;
440             PetscCDPos pos,last=NULL;
441             /* looking for local from local so id_llist_2 works */
442             ierr = PetscCDGetHeadPos(aggs_2,slid,&pos);CHKERRQ(ierr);
443             while (pos) {
444               PetscInt gid;
445               ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
446               if (gid == gidj) {
447                 if (!last) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"last cannot be null");
448                 ierr = PetscCDRemoveNextNode(aggs_2, slid, last);CHKERRQ(ierr);
449                 ierr = PetscCDAppendNode(aggs_2, lid, pos);CHKERRQ(ierr);
450                 hav  = 1;
451                 break;
452               } else last = pos;
453 
454               ierr = PetscCDGetNextPos(aggs_2,slid,&pos);CHKERRQ(ierr);
455             }
456             if (hav!=1) {
457               if (!hav) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
458               SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
459             }
460           } else {            /* I'm stealing this local, owned by a ghost */
461             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.");
462             ierr = PetscCDAppendID(aggs_2, lid, lidj+my0);CHKERRQ(ierr);
463           }
464         }
465       } /* local neighbors */
466     } else if (state == DELETED && lid_cprowID_1) {
467       PetscInt sgidold = (PetscInt)PetscRealPart(lid_parent_gid[lid]);
468       /* see if I have a selected ghost neighbor that will steal me */
469       if ((ix=lid_cprowID_1[lid]) != -1) {
470         ii  = matB_1->compressedrow.i; n = ii[ix+1] - ii[ix];
471         idx = matB_1->j + ii[ix];
472         for (j=0; j<n; j++) {
473           PetscInt cpid   = idx[j];
474           NState   statej = (NState)PetscRealPart(cpcol_1_state[cpid]);
475           if (IS_SELECTED(statej) && sgidold != (PetscInt)statej) { /* ghost will steal this, remove from my list */
476             lid_parent_gid[lid] = (PetscScalar)statej; /* send who selected */
477             if (sgidold>=my0 && sgidold<Iend) { /* this was mine */
478               PetscInt   hav=0,oldslidj=sgidold-my0;
479               PetscCDPos pos,last=NULL;
480               /* remove from 'oldslidj' list */
481               ierr = PetscCDGetHeadPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
482               while (pos) {
483                 PetscInt gid;
484                 ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
485                 if (lid+my0 == gid) {
486                   /* id_llist_2[lastid] = id_llist_2[flid];   /\* remove lid from oldslidj list *\/ */
487                   if (!last) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"last cannot be null");
488                   ierr = PetscCDRemoveNextNode(aggs_2, oldslidj, last);CHKERRQ(ierr);
489                   /* ghost (PetscScalar)statej will add this later */
490                   hav = 1;
491                   break;
492                 } else last = pos;
493 
494                 ierr = PetscCDGetNextPos(aggs_2,oldslidj,&pos);CHKERRQ(ierr);
495               }
496               if (hav!=1) {
497                 if (hav==0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"failed to find adj in 'selected' lists - structurally unsymmetric matrix");
498                 SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"found node %d times???",hav);
499               }
500             } else {
501               /* ghosts remove this later */
502             }
503           }
504         }
505       }
506     } /* selected/deleted */
507   } /* node loop */
508 
509   if (isMPI) {
510     PetscScalar   *cpcol_2_parent,*cpcol_2_gid;
511     Vec           tempVec,ghostgids2,ghostparents2;
512     PetscInt      cpid,nghost_2;
513     GAMGHashTable gid_cpid;
514 
515     ierr = VecGetSize(mpimat_2->lvec, &nghost_2);CHKERRQ(ierr);
516     ierr = MatCreateVecs(Gmat_2, &tempVec, 0);CHKERRQ(ierr);
517 
518     /* get 'cpcol_2_parent' */
519     for (kk=0,j=my0; kk<nloc; kk++,j++) {
520       ierr = VecSetValues(tempVec, 1, &j, &lid_parent_gid[kk], INSERT_VALUES);CHKERRQ(ierr);
521     }
522     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
523     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
524     ierr = VecDuplicate(mpimat_2->lvec, &ghostparents2);CHKERRQ(ierr);
525     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
526     ierr = VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostparents2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
527     ierr = VecGetArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
528 
529     /* get 'cpcol_2_gid' */
530     for (kk=0,j=my0; kk<nloc; kk++,j++) {
531       PetscScalar v = (PetscScalar)j;
532       ierr = VecSetValues(tempVec, 1, &j, &v, INSERT_VALUES);CHKERRQ(ierr);
533     }
534     ierr = VecAssemblyBegin(tempVec);CHKERRQ(ierr);
535     ierr = VecAssemblyEnd(tempVec);CHKERRQ(ierr);
536     ierr = VecDuplicate(mpimat_2->lvec, &ghostgids2);CHKERRQ(ierr);
537     ierr = VecScatterBegin(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
538     ierr = VecScatterEnd(mpimat_2->Mvctx,tempVec, ghostgids2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
539     ierr = VecGetArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
540 
541     ierr = VecDestroy(&tempVec);CHKERRQ(ierr);
542 
543     /* look for deleted ghosts and add to table */
544     ierr = GAMGTableCreate(2*nghost_2+1, &gid_cpid);CHKERRQ(ierr);
545     for (cpid = 0; cpid < nghost_2; cpid++) {
546       NState state = (NState)PetscRealPart(cpcol_2_state[cpid]);
547       if (state==DELETED) {
548         PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
549         PetscInt sgid_old = (PetscInt)PetscRealPart(cpcol_2_par_orig[cpid]);
550         if (sgid_old == -1 && sgid_new != -1) {
551           PetscInt gid = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
552           ierr = GAMGTableAdd(&gid_cpid, gid, cpid);CHKERRQ(ierr);
553         }
554       }
555     }
556 
557     /* look for deleted ghosts and see if they moved - remove it */
558     for (lid=0; lid<nloc; lid++) {
559       NState state = lid_state[lid];
560       if (IS_SELECTED(state)) {
561         PetscCDPos pos,last=NULL;
562         /* look for deleted ghosts and see if they moved */
563         ierr = PetscCDGetHeadPos(aggs_2,lid,&pos);CHKERRQ(ierr);
564         while (pos) {
565           PetscInt gid;
566           ierr = PetscLLNGetID(pos, &gid);CHKERRQ(ierr);
567 
568           if (gid < my0 || gid >= Iend) {
569             ierr = GAMGTableFind(&gid_cpid, gid, &cpid);CHKERRQ(ierr);
570             if (cpid != -1) {
571               /* a moved ghost - */
572               /* id_llist_2[lastid] = id_llist_2[flid];    /\* remove 'flid' from list *\/ */
573               ierr = PetscCDRemoveNextNode(aggs_2, lid, last);CHKERRQ(ierr);
574             } else last = pos;
575           } else last = pos;
576 
577           ierr = PetscCDGetNextPos(aggs_2,lid,&pos);CHKERRQ(ierr);
578         } /* loop over list of deleted */
579       } /* selected */
580     }
581     ierr = GAMGTableDestroy(&gid_cpid);CHKERRQ(ierr);
582 
583     /* look at ghosts, see if they changed - and it */
584     for (cpid = 0; cpid < nghost_2; cpid++) {
585       PetscInt sgid_new = (PetscInt)PetscRealPart(cpcol_2_parent[cpid]);
586       if (sgid_new >= my0 && sgid_new < Iend) { /* this is mine */
587         PetscInt   gid     = (PetscInt)PetscRealPart(cpcol_2_gid[cpid]);
588         PetscInt   slid_new=sgid_new-my0,hav=0;
589         PetscCDPos pos;
590         /* search for this gid to see if I have it */
591         ierr = PetscCDGetHeadPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
592         while (pos) {
593           PetscInt gidj;
594           ierr = PetscLLNGetID(pos, &gidj);CHKERRQ(ierr);
595           ierr = PetscCDGetNextPos(aggs_2,slid_new,&pos);CHKERRQ(ierr);
596 
597           if (gidj == gid) { hav = 1; break; }
598         }
599         if (hav != 1) {
600           /* insert 'flidj' into head of llist */
601           ierr = PetscCDAppendID(aggs_2, slid_new, gid);CHKERRQ(ierr);
602         }
603       }
604     }
605 
606     ierr = VecRestoreArray(mpimat_1->lvec, &cpcol_1_state);CHKERRQ(ierr);
607     ierr = VecRestoreArray(mpimat_2->lvec, &cpcol_2_state);CHKERRQ(ierr);
608     ierr = VecRestoreArray(ghostparents2, &cpcol_2_parent);CHKERRQ(ierr);
609     ierr = VecRestoreArray(ghostgids2, &cpcol_2_gid);CHKERRQ(ierr);
610     ierr = PetscFree(lid_cprowID_1);CHKERRQ(ierr);
611     ierr = VecDestroy(&ghostgids2);CHKERRQ(ierr);
612     ierr = VecDestroy(&ghostparents2);CHKERRQ(ierr);
613     ierr = VecDestroy(&ghost_par_orig2);CHKERRQ(ierr);
614   }
615 
616   ierr = PetscFree2(lid_state,lid_parent_gid);CHKERRQ(ierr);
617   PetscFunctionReturn(0);
618 }
619 
620 /* -------------------------------------------------------------------------- */
621 /*
622    PCSetData_AGG - called if data is not set with PCSetCoordinates.
623       Looks in Mat for near null space.
624       Does not work for Stokes
625 
626   Input Parameter:
627    . pc -
628    . a_A - matrix to get (near) null space out of.
629 */
630 #undef __FUNCT__
631 #define __FUNCT__ "PCSetData_AGG"
632 PetscErrorCode PCSetData_AGG(PC pc, Mat a_A)
633 {
634   PetscErrorCode ierr;
635   PC_MG          *mg      = (PC_MG*)pc->data;
636   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
637   MatNullSpace   mnull;
638 
639   PetscFunctionBegin;
640   ierr = MatGetNearNullSpace(a_A, &mnull);CHKERRQ(ierr);
641   if (!mnull) {
642     PetscInt bs,NN,MM;
643     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr);
644     ierr = MatGetLocalSize(a_A, &MM, &NN);CHKERRQ(ierr);
645     if (MM % bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MM %D must be divisible by bs %D",MM,bs);
646     ierr = PCSetCoordinates_AGG(pc, bs, MM/bs, NULL);CHKERRQ(ierr);
647   } else {
648     PetscReal *nullvec;
649     PetscBool has_const;
650     PetscInt  i,j,mlocal,nvec,bs;
651     const Vec *vecs; const PetscScalar *v;
652     ierr = MatGetLocalSize(a_A,&mlocal,NULL);CHKERRQ(ierr);
653     ierr = MatNullSpaceGetVecs(mnull, &has_const, &nvec, &vecs);CHKERRQ(ierr);
654     pc_gamg->data_sz = (nvec+!!has_const)*mlocal;
655     ierr = PetscMalloc1((nvec+!!has_const)*mlocal,&nullvec);CHKERRQ(ierr);
656     if (has_const) for (i=0; i<mlocal; i++) nullvec[i] = 1.0;
657     for (i=0; i<nvec; i++) {
658       ierr = VecGetArrayRead(vecs[i],&v);CHKERRQ(ierr);
659       for (j=0; j<mlocal; j++) nullvec[(i+!!has_const)*mlocal + j] = PetscRealPart(v[j]);
660       ierr = VecRestoreArrayRead(vecs[i],&v);CHKERRQ(ierr);
661     }
662     pc_gamg->data           = nullvec;
663     pc_gamg->data_cell_cols = (nvec+!!has_const);
664 
665     ierr = MatGetBlockSize(a_A, &bs);CHKERRQ(ierr);
666 
667     pc_gamg->data_cell_rows = bs;
668   }
669   PetscFunctionReturn(0);
670 }
671 
672 /* -------------------------------------------------------------------------- */
673 /*
674  formProl0
675 
676    Input Parameter:
677    . agg_llists - list of arrays with aggregates -- list from selected vertices of aggregate unselected vertices
678    . bs - row block size
679    . nSAvec - column bs of new P
680    . my0crs - global index of start of locals
681    . data_stride - bs*(nloc nodes + ghost nodes) [data_stride][nSAvec]
682    . data_in[data_stride*nSAvec] - local data on fine grid
683    . flid_fgid[data_stride/bs] - make local to global IDs, includes ghosts in 'locals_llist'
684   Output Parameter:
685    . a_data_out - in with fine grid data (w/ghosts), out with coarse grid data
686    . a_Prol - prolongation operator
687 */
688 #undef __FUNCT__
689 #define __FUNCT__ "formProl0"
690 static PetscErrorCode formProl0(PetscCoarsenData *agg_llists,PetscInt bs,PetscInt nSAvec,PetscInt my0crs,PetscInt data_stride,PetscReal data_in[],const PetscInt flid_fgid[],PetscReal **a_data_out,Mat a_Prol)
691 {
692   PetscErrorCode ierr;
693   PetscInt       Istart,my0,Iend,nloc,clid,flid = 0,aggID,kk,jj,ii,mm,ndone,nSelected,minsz,nghosts,out_data_stride;
694   MPI_Comm       comm;
695   PetscMPIInt    rank;
696   PetscReal      *out_data;
697   PetscCDPos     pos;
698   GAMGHashTable  fgid_flid;
699 
700 /* #define OUT_AGGS */
701 #if defined(OUT_AGGS)
702   static PetscInt llev = 0; char fname[32]; FILE *file = NULL; PetscInt pM;
703 #endif
704 
705   PetscFunctionBegin;
706   ierr = PetscObjectGetComm((PetscObject)a_Prol,&comm);CHKERRQ(ierr);
707   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
708   ierr = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
709   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
710   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Iend %D - Istart %d must be divisible by bs %D",Iend,Istart,bs);
711   Iend   /= bs;
712   nghosts = data_stride/bs - nloc;
713 
714   ierr = GAMGTableCreate(2*nghosts+1, &fgid_flid);CHKERRQ(ierr);
715   for (kk=0; kk<nghosts; kk++) {
716     ierr = GAMGTableAdd(&fgid_flid, flid_fgid[nloc+kk], nloc+kk);CHKERRQ(ierr);
717   }
718 
719 #if defined(OUT_AGGS)
720   sprintf(fname,"aggs_%d_%d.m",llev++,rank);
721   if (llev==1) file = fopen(fname,"w");
722   MatGetSize(a_Prol, &pM, &jj);
723 #endif
724 
725   /* count selected -- same as number of cols of P */
726   for (nSelected=mm=0; mm<nloc; mm++) {
727     PetscBool ise;
728     ierr = PetscCDEmptyAt(agg_llists, mm, &ise);CHKERRQ(ierr);
729     if (!ise) nSelected++;
730   }
731   ierr = MatGetOwnershipRangeColumn(a_Prol, &ii, &jj);CHKERRQ(ierr);
732   if ((ii/nSAvec) != my0crs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"ii %D /nSAvec %D  != my0crs %D",ii,nSAvec,my0crs);
733   if (nSelected != (jj-ii)/nSAvec) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nSelected %D != (jj %D - ii %D)/nSAvec %D",nSelected,jj,ii,nSAvec);
734 
735   /* aloc space for coarse point data (output) */
736   out_data_stride = nSelected*nSAvec;
737 
738   ierr = PetscMalloc1(out_data_stride*nSAvec, &out_data);CHKERRQ(ierr);
739   for (ii=0;ii<out_data_stride*nSAvec;ii++) out_data[ii]=PETSC_MAX_REAL;
740   *a_data_out = out_data; /* output - stride nSelected*nSAvec */
741 
742   /* find points and set prolongation */
743   minsz = 100;
744   ndone = 0;
745   for (mm = clid = 0; mm < nloc; mm++) {
746     ierr = PetscCDSizeAt(agg_llists, mm, &jj);CHKERRQ(ierr);
747     if (jj > 0) {
748       const PetscInt lid = mm, cgid = my0crs + clid;
749       PetscInt       cids[100]; /* max bs */
750       PetscBLASInt   asz  =jj,M=asz*bs,N=nSAvec,INFO;
751       PetscBLASInt   Mdata=M+((N-M>0) ? N-M : 0),LDA=Mdata,LWORK=N*bs;
752       PetscScalar    *qqc,*qqr,*TAU,*WORK;
753       PetscInt       *fids;
754       PetscReal      *data;
755       /* count agg */
756       if (asz<minsz) minsz = asz;
757 
758       /* get block */
759       ierr = PetscMalloc5(Mdata*N, &qqc,M*N, &qqr,N, &TAU,LWORK, &WORK,M, &fids);CHKERRQ(ierr);
760 
761       aggID = 0;
762       ierr  = PetscCDGetHeadPos(agg_llists,lid,&pos);CHKERRQ(ierr);
763       while (pos) {
764         PetscInt gid1;
765         ierr = PetscLLNGetID(pos, &gid1);CHKERRQ(ierr);
766         ierr = PetscCDGetNextPos(agg_llists,lid,&pos);CHKERRQ(ierr);
767 
768         if (gid1 >= my0 && gid1 < Iend) flid = gid1 - my0;
769         else {
770           ierr = GAMGTableFind(&fgid_flid, gid1, &flid);CHKERRQ(ierr);
771           if (flid < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot find gid1 in table");
772         }
773         /* copy in B_i matrix - column oriented */
774         data = &data_in[flid*bs];
775         for (kk = ii = 0; ii < bs; ii++) {
776           for (jj = 0; jj < N; jj++) {
777             PetscReal d = data[jj*data_stride + ii];
778             qqc[jj*Mdata + aggID*bs + ii] = d;
779           }
780         }
781 #if defined(OUT_AGGS)
782         if (llev==1) {
783           char     str[] = "plot(%e,%e,'r*'), hold on,\n", col[] = "rgbkmc", sim[] = "*os+h>d<vx^";
784           PetscInt MM,pi,pj;
785           str[12] = col[(clid+17*rank)%6]; str[13] = sim[(clid+17*rank)%11];
786           MM      = (PetscInt)(PetscSqrtReal((PetscReal)pM));
787           pj      = gid1/MM; pi = gid1%MM;
788           fprintf(file,str,(double)pi,(double)pj);
789           /* fprintf(file,str,data[2*data_stride+1],-data[2*data_stride]); */
790         }
791 #endif
792         /* set fine IDs */
793         for (kk=0; kk<bs; kk++) fids[aggID*bs + kk] = flid_fgid[flid]*bs + kk;
794 
795         aggID++;
796       }
797 
798       /* pad with zeros */
799       for (ii = asz*bs; ii < Mdata; ii++) {
800         for (jj = 0; jj < N; jj++, kk++) {
801           qqc[jj*Mdata + ii] = .0;
802         }
803       }
804 
805       ndone += aggID;
806       /* QR */
807       ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
808       PetscStackCallBLAS("LAPACKgeqrf",LAPACKgeqrf_(&Mdata, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO));
809       ierr = PetscFPTrapPop();CHKERRQ(ierr);
810       if (INFO != 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xGEQRF error");
811       /* get R - column oriented - output B_{i+1} */
812       {
813         PetscReal *data = &out_data[clid*nSAvec];
814         for (jj = 0; jj < nSAvec; jj++) {
815           for (ii = 0; ii < nSAvec; ii++) {
816             if (data[jj*out_data_stride + ii] != PETSC_MAX_REAL) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"data[jj*out_data_stride + ii] != %e",PETSC_MAX_REAL);
817            if (ii <= jj) data[jj*out_data_stride + ii] = PetscRealPart(qqc[jj*Mdata + ii]);
818            else data[jj*out_data_stride + ii] = 0.;
819           }
820         }
821       }
822 
823       /* get Q - row oriented */
824       PetscStackCallBLAS("LAPACKungqr",LAPACKungqr_(&Mdata, &N, &N, qqc, &LDA, TAU, WORK, &LWORK, &INFO));
825       if (INFO != 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"xORGQR error arg %d",-INFO);
826 
827       for (ii = 0; ii < M; ii++) {
828         for (jj = 0; jj < N; jj++) {
829           qqr[N*ii + jj] = qqc[jj*Mdata + ii];
830         }
831       }
832 
833       /* add diagonal block of P0 */
834       for (kk=0; kk<N; kk++) {
835         cids[kk] = N*cgid + kk; /* global col IDs in P0 */
836       }
837       ierr = MatSetValues(a_Prol,M,fids,N,cids,qqr,INSERT_VALUES);CHKERRQ(ierr);
838 
839       ierr = PetscFree5(qqc,qqr,TAU,WORK,fids);CHKERRQ(ierr);
840       clid++;
841     } /* coarse agg */
842   } /* for all fine nodes */
843   ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
844   ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
845 
846 /* ierr = MPI_Allreduce(&ndone, &ii, 1, MPIU_INT, MPIU_SUM, comm); */
847 /* MatGetSize(a_Prol, &kk, &jj); */
848 /* ierr = MPI_Allreduce(&minsz, &jj, 1, MPIU_INT, MPIU_MIN, comm); */
849 /* PetscPrintf(comm," **** [%d]%s %d total done, %d nodes (%d local done), min agg. size = %d\n",rank,__FUNCT__,ii,kk/bs,ndone,jj); */
850 
851 #if defined(OUT_AGGS)
852   if (llev==1) fclose(file);
853 #endif
854   ierr = GAMGTableDestroy(&fgid_flid);CHKERRQ(ierr);
855   PetscFunctionReturn(0);
856 }
857 
858 #undef __FUNCT__
859 #define __FUNCT__ "PCView_GAMG_AGG"
860 static PetscErrorCode PCView_GAMG_AGG(PC pc,PetscViewer viewer)
861 {
862   PetscErrorCode ierr;
863   PC_MG          *mg      = (PC_MG*)pc->data;
864   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
865   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
866 
867   PetscFunctionBegin;
868   ierr = PetscViewerASCIIPrintf(viewer,"      AGG specific options\n");CHKERRQ(ierr);
869   ierr = PetscViewerASCIIPrintf(viewer,"        Symmetric graph %s\n",pc_gamg_agg->sym_graph ? "true" : "false");CHKERRQ(ierr);
870   PetscFunctionReturn(0);
871 }
872 
873 /* -------------------------------------------------------------------------- */
874 /*
875    PCGAMGGraph_AGG
876 
877   Input Parameter:
878    . pc - this
879    . Amat - matrix on this fine level
880   Output Parameter:
881    . a_Gmat -
882 */
883 #undef __FUNCT__
884 #define __FUNCT__ "PCGAMGGraph_AGG"
885 PetscErrorCode PCGAMGGraph_AGG(PC pc,Mat Amat,Mat *a_Gmat)
886 {
887   PetscErrorCode            ierr;
888   PC_MG                     *mg          = (PC_MG*)pc->data;
889   PC_GAMG                   *pc_gamg     = (PC_GAMG*)mg->innerctx;
890   const PetscReal           vfilter      = pc_gamg->threshold;
891   PC_GAMG_AGG               *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
892   Mat                       Gmat;
893   MPI_Comm                  comm;
894   PetscBool /* set,flg , */ symm;
895 
896   PetscFunctionBegin;
897   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
898   ierr = PetscLogEventBegin(PC_GAMGGraph_AGG,0,0,0,0);CHKERRQ(ierr);
899 
900   /* ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr); || !(set && flg) -- this causes lot of symm calls */
901   symm = (PetscBool)(pc_gamg_agg->sym_graph); /* && !pc_gamg_agg->square_graph; */
902 
903   ierr = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
904   ierr = PCGAMGFilterGraph(&Gmat, vfilter, symm);CHKERRQ(ierr);
905 
906   *a_Gmat = Gmat;
907 
908   ierr = PetscLogEventEnd(PC_GAMGGraph_AGG,0,0,0,0);CHKERRQ(ierr);
909   PetscFunctionReturn(0);
910 }
911 
912 /* -------------------------------------------------------------------------- */
913 /*
914    PCGAMGCoarsen_AGG
915 
916   Input Parameter:
917    . a_pc - this
918   Input/Output Parameter:
919    . a_Gmat1 - graph on this fine level - coarsening can change this (squares it)
920   Output Parameter:
921    . agg_lists - list of aggregates
922 */
923 #undef __FUNCT__
924 #define __FUNCT__ "PCGAMGCoarsen_AGG"
925 PetscErrorCode PCGAMGCoarsen_AGG(PC a_pc,Mat *a_Gmat1,PetscCoarsenData **agg_lists)
926 {
927   PetscErrorCode ierr;
928   PC_MG          *mg          = (PC_MG*)a_pc->data;
929   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
930   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
931   Mat            mat,Gmat2, Gmat1 = *a_Gmat1;  /* squared graph */
932   IS             perm;
933   PetscInt       Ii,nloc,bs,n,m;
934   PetscInt       *permute;
935   PetscBool      *bIndexSet;
936   MatCoarsen     crs;
937   MPI_Comm       comm;
938   PetscMPIInt    rank;
939 
940   PetscFunctionBegin;
941   ierr = PetscLogEventBegin(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
942   ierr = PetscObjectGetComm((PetscObject)Gmat1,&comm);CHKERRQ(ierr);
943   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
944   ierr = MatGetLocalSize(Gmat1, &n, &m);CHKERRQ(ierr);
945   ierr = MatGetBlockSize(Gmat1, &bs);CHKERRQ(ierr);
946   if (bs != 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"bs %D must be 1",bs);
947   nloc = n/bs;
948 
949   if (pc_gamg->current_level < pc_gamg_agg->square_graph) {
950     ierr = PetscInfo2(a_pc,"Square Graph on level %d of %d to square\n",pc_gamg->current_level+1,pc_gamg_agg->square_graph);
951     CHKERRQ(ierr);
952     /* ierr = MatMatTransposeMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2); */
953     ierr = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
954   } else Gmat2 = Gmat1;
955 
956   /* get MIS aggs */
957   /* randomize */
958   ierr = PetscMalloc1(nloc, &permute);CHKERRQ(ierr);
959   ierr = PetscMalloc1(nloc, &bIndexSet);CHKERRQ(ierr);
960   for (Ii = 0; Ii < nloc; Ii++) {
961     bIndexSet[Ii] = PETSC_FALSE;
962     permute[Ii]   = Ii;
963   }
964   srand(1); /* make deterministic */
965   for (Ii = 0; Ii < nloc; Ii++) {
966     PetscInt iSwapIndex = rand()%nloc;
967     if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
968       PetscInt iTemp = permute[iSwapIndex];
969       permute[iSwapIndex]   = permute[Ii];
970       permute[Ii]           = iTemp;
971       bIndexSet[iSwapIndex] = PETSC_TRUE;
972     }
973   }
974   ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
975 
976   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_USE_POINTER, &perm);CHKERRQ(ierr);
977 #if defined PETSC_GAMG_USE_LOG
978   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
979 #endif
980   ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
981   /* ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr); */
982   ierr = MatCoarsenSetFromOptions(crs);CHKERRQ(ierr);
983   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
984   ierr = MatCoarsenSetAdjacency(crs, Gmat2);CHKERRQ(ierr);
985   ierr = MatCoarsenSetStrictAggs(crs, PETSC_TRUE);CHKERRQ(ierr);
986   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
987   ierr = MatCoarsenGetData(crs, agg_lists);CHKERRQ(ierr); /* output */
988   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
989 
990   ierr = ISDestroy(&perm);CHKERRQ(ierr);
991   ierr = PetscFree(permute);CHKERRQ(ierr);
992 #if defined PETSC_GAMG_USE_LOG
993   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET4],0,0,0,0);CHKERRQ(ierr);
994 #endif
995 
996   /* smooth aggs */
997   if (Gmat2 != Gmat1) {
998     const PetscCoarsenData *llist = *agg_lists;
999     ierr     = smoothAggs(Gmat2, Gmat1, *agg_lists);CHKERRQ(ierr);
1000     ierr     = MatDestroy(&Gmat1);CHKERRQ(ierr);
1001     *a_Gmat1 = Gmat2; /* output */
1002     ierr     = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1003     if (mat) SETERRQ(comm,PETSC_ERR_ARG_WRONG, "Auxilary matrix with squared graph????");
1004   } else {
1005     const PetscCoarsenData *llist = *agg_lists;
1006     /* see if we have a matrix that takes precedence (returned from MatCoarsenApply) */
1007     ierr = PetscCDGetMat(llist, &mat);CHKERRQ(ierr);
1008     if (mat) {
1009       ierr     = MatDestroy(&Gmat1);CHKERRQ(ierr);
1010       *a_Gmat1 = mat; /* output */
1011     }
1012   }
1013   ierr = PetscLogEventEnd(PC_GAMGCoarsen_AGG,0,0,0,0);CHKERRQ(ierr);
1014   PetscFunctionReturn(0);
1015 }
1016 
1017 /* -------------------------------------------------------------------------- */
1018 /*
1019  PCGAMGProlongator_AGG
1020 
1021  Input Parameter:
1022  . pc - this
1023  . Amat - matrix on this fine level
1024  . Graph - used to get ghost data for nodes in
1025  . agg_lists - list of aggregates
1026  Output Parameter:
1027  . a_P_out - prolongation operator to the next level
1028  */
1029 #undef __FUNCT__
1030 #define __FUNCT__ "PCGAMGProlongator_AGG"
1031 PetscErrorCode PCGAMGProlongator_AGG(PC pc,Mat Amat,Mat Gmat,PetscCoarsenData *agg_lists,Mat *a_P_out)
1032 {
1033   PC_MG          *mg       = (PC_MG*)pc->data;
1034   PC_GAMG        *pc_gamg  = (PC_GAMG*)mg->innerctx;
1035   const PetscInt data_cols = pc_gamg->data_cell_cols;
1036   PetscErrorCode ierr;
1037   PetscInt       Istart,Iend,nloc,ii,jj,kk,my0,nLocalSelected,bs;
1038   Mat            Prol;
1039   PetscMPIInt    rank, size;
1040   MPI_Comm       comm;
1041   const PetscInt col_bs = data_cols;
1042   PetscReal      *data_w_ghost;
1043   PetscInt       myCrs0, nbnodes=0, *flid_fgid;
1044   MatType        mtype;
1045 
1046   PetscFunctionBegin;
1047   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1048   ierr = PetscLogEventBegin(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1049   ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
1050   ierr = MPI_Comm_size(comm, &size);CHKERRQ(ierr);
1051   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1052   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
1053   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
1054   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(Iend %D - Istart %D) not divisible by bs %D",Iend,Istart,bs);
1055 
1056   /* get 'nLocalSelected' */
1057   for (ii=0, nLocalSelected = 0; ii < nloc; ii++) {
1058     PetscBool ise;
1059     /* filter out singletons 0 or 1? */
1060     ierr = PetscCDEmptyAt(agg_lists, ii, &ise);CHKERRQ(ierr);
1061     if (!ise) nLocalSelected++;
1062   }
1063 
1064   /* create prolongator, create P matrix */
1065   ierr = MatGetType(Amat,&mtype);CHKERRQ(ierr);
1066   ierr = MatCreate(comm, &Prol);CHKERRQ(ierr);
1067   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*col_bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
1068   ierr = MatSetBlockSizes(Prol, bs, col_bs);CHKERRQ(ierr);
1069   ierr = MatSetType(Prol, mtype);CHKERRQ(ierr);
1070   ierr = MatSeqAIJSetPreallocation(Prol, data_cols, NULL);CHKERRQ(ierr);
1071   ierr = MatMPIAIJSetPreallocation(Prol,data_cols, NULL,data_cols, NULL);CHKERRQ(ierr);
1072   /* nloc*bs, nLocalSelected*col_bs, */
1073   /* PETSC_DETERMINE, PETSC_DETERMINE, */
1074   /* data_cols, NULL, data_cols, NULL, */
1075   /* &Prol); */
1076 
1077   /* can get all points "removed" */
1078   ierr =  MatGetSize(Prol, &kk, &ii);CHKERRQ(ierr);
1079   if (ii==0) {
1080     ierr = PetscInfo(pc,"No selected points on coarse grid\n");CHKERRQ(ierr);
1081     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
1082     *a_P_out = NULL;  /* out */
1083     PetscFunctionReturn(0);
1084   }
1085   ierr = PetscInfo1(pc,"New grid %D nodes\n",ii/col_bs);CHKERRQ(ierr);
1086   ierr = MatGetOwnershipRangeColumn(Prol, &myCrs0, &kk);CHKERRQ(ierr);
1087 
1088   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);
1089   myCrs0 = myCrs0/col_bs;
1090   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);
1091 
1092   /* create global vector of data in 'data_w_ghost' */
1093 #if defined PETSC_GAMG_USE_LOG
1094   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1095 #endif
1096   if (size > 1) { /*  */
1097     PetscReal *tmp_gdata,*tmp_ldata,*tp2;
1098     ierr = PetscMalloc1(nloc, &tmp_ldata);CHKERRQ(ierr);
1099     for (jj = 0; jj < data_cols; jj++) {
1100       for (kk = 0; kk < bs; kk++) {
1101         PetscInt        ii,stride;
1102         const PetscReal *tp = pc_gamg->data + jj*bs*nloc + kk;
1103         for (ii = 0; ii < nloc; ii++, tp += bs) tmp_ldata[ii] = *tp;
1104 
1105         ierr = PCGAMGGetDataWithGhosts(Gmat, 1, tmp_ldata, &stride, &tmp_gdata);CHKERRQ(ierr);
1106 
1107         if (jj==0 && kk==0) { /* now I know how many todal nodes - allocate */
1108           ierr    = PetscMalloc1(stride*bs*data_cols, &data_w_ghost);CHKERRQ(ierr);
1109           nbnodes = bs*stride;
1110         }
1111         tp2 = data_w_ghost + jj*bs*stride + kk;
1112         for (ii = 0; ii < stride; ii++, tp2 += bs) *tp2 = tmp_gdata[ii];
1113         ierr = PetscFree(tmp_gdata);CHKERRQ(ierr);
1114       }
1115     }
1116     ierr = PetscFree(tmp_ldata);CHKERRQ(ierr);
1117   } else {
1118     nbnodes      = bs*nloc;
1119     data_w_ghost = (PetscReal*)pc_gamg->data;
1120   }
1121 
1122   /* get P0 */
1123   if (size > 1) {
1124     PetscReal *fid_glid_loc,*fiddata;
1125     PetscInt  stride;
1126 
1127     ierr = PetscMalloc1(nloc, &fid_glid_loc);CHKERRQ(ierr);
1128     for (kk=0; kk<nloc; kk++) fid_glid_loc[kk] = (PetscReal)(my0+kk);
1129     ierr = PCGAMGGetDataWithGhosts(Gmat, 1, fid_glid_loc, &stride, &fiddata);CHKERRQ(ierr);
1130     ierr = PetscMalloc1(stride, &flid_fgid);CHKERRQ(ierr);
1131     for (kk=0; kk<stride; kk++) flid_fgid[kk] = (PetscInt)fiddata[kk];
1132     ierr = PetscFree(fiddata);CHKERRQ(ierr);
1133 
1134     if (stride != nbnodes/bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"stride %D != nbnodes %D/bs %D",stride,nbnodes,bs);
1135     ierr = PetscFree(fid_glid_loc);CHKERRQ(ierr);
1136   } else {
1137     ierr = PetscMalloc1(nloc, &flid_fgid);CHKERRQ(ierr);
1138     for (kk=0; kk<nloc; kk++) flid_fgid[kk] = my0 + kk;
1139   }
1140 #if defined PETSC_GAMG_USE_LOG
1141   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET7],0,0,0,0);CHKERRQ(ierr);
1142   ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1143 #endif
1144   {
1145     PetscReal *data_out = NULL;
1146     ierr = formProl0(agg_lists, bs, data_cols, myCrs0, nbnodes,data_w_ghost, flid_fgid, &data_out, Prol);CHKERRQ(ierr);
1147     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
1148 
1149     pc_gamg->data           = data_out;
1150     pc_gamg->data_cell_rows = data_cols;
1151     pc_gamg->data_sz        = data_cols*data_cols*nLocalSelected;
1152   }
1153 #if defined PETSC_GAMG_USE_LOG
1154   ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET8],0,0,0,0);CHKERRQ(ierr);
1155 #endif
1156   if (size > 1) ierr = PetscFree(data_w_ghost);CHKERRQ(ierr);
1157   ierr = PetscFree(flid_fgid);CHKERRQ(ierr);
1158 
1159   *a_P_out = Prol;  /* out */
1160 
1161   ierr = PetscLogEventEnd(PC_GAMGProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1162   PetscFunctionReturn(0);
1163 }
1164 
1165 /* -------------------------------------------------------------------------- */
1166 /*
1167    PCGAMGOptProlongator_AGG
1168 
1169   Input Parameter:
1170    . pc - this
1171    . Amat - matrix on this fine level
1172  In/Output Parameter:
1173    . a_P_out - prolongation operator to the next level
1174 */
1175 #undef __FUNCT__
1176 #define __FUNCT__ "PCGAMGOptProlongator_AGG"
1177 PetscErrorCode PCGAMGOptProlongator_AGG(PC pc,Mat Amat,Mat *a_P)
1178 {
1179   PetscErrorCode ierr;
1180   PC_MG          *mg          = (PC_MG*)pc->data;
1181   PC_GAMG        *pc_gamg     = (PC_GAMG*)mg->innerctx;
1182   PC_GAMG_AGG    *pc_gamg_agg = (PC_GAMG_AGG*)pc_gamg->subctx;
1183   PetscInt       jj;
1184   Mat            Prol  = *a_P;
1185   MPI_Comm       comm;
1186 
1187   PetscFunctionBegin;
1188   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1189   ierr = PetscLogEventBegin(PC_GAMGOptProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1190 
1191   /* smooth P0 */
1192   for (jj = 0; jj < pc_gamg_agg->nsmooths; jj++) {
1193     Mat       tMat;
1194     Vec       diag;
1195     PetscReal alpha, emax, emin;
1196 #if defined PETSC_GAMG_USE_LOG
1197     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1198 #endif
1199     if (jj == 0) {
1200       KSP eksp;
1201       Vec bb, xx;
1202       PC  epc;
1203       ierr = MatCreateVecs(Amat, &bb, 0);CHKERRQ(ierr);
1204       ierr = MatCreateVecs(Amat, &xx, 0);CHKERRQ(ierr);
1205       {
1206         PetscRandom rctx;
1207         ierr = PetscRandomCreate(comm,&rctx);CHKERRQ(ierr);
1208         ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
1209         ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
1210         ierr = PetscRandomDestroy(&rctx);CHKERRQ(ierr);
1211       }
1212 
1213       /* zeroing out BC rows -- needed for crazy matrices */
1214       {
1215         PetscInt    Istart,Iend,ncols,jj,Ii;
1216         PetscScalar zero = 0.0;
1217         ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
1218         for (Ii = Istart, jj = 0; Ii < Iend; Ii++, jj++) {
1219           ierr = MatGetRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1220           if (ncols <= 1) {
1221             ierr = VecSetValues(bb, 1, &Ii, &zero, INSERT_VALUES);CHKERRQ(ierr);
1222           }
1223           ierr = MatRestoreRow(Amat,Ii,&ncols,0,0);CHKERRQ(ierr);
1224         }
1225         ierr = VecAssemblyBegin(bb);CHKERRQ(ierr);
1226         ierr = VecAssemblyEnd(bb);CHKERRQ(ierr);
1227       }
1228 
1229       ierr = KSPCreate(comm,&eksp);CHKERRQ(ierr);
1230       ierr = KSPSetErrorIfNotConverged(eksp,pc->erroriffailure);CHKERRQ(ierr);
1231       ierr = KSPSetTolerances(eksp,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,10);CHKERRQ(ierr);
1232       ierr = KSPSetNormType(eksp, KSP_NORM_NONE);CHKERRQ(ierr);
1233       ierr = KSPSetOptionsPrefix(eksp,((PetscObject)pc)->prefix);CHKERRQ(ierr);
1234       ierr = KSPAppendOptionsPrefix(eksp, "gamg_est_");CHKERRQ(ierr);
1235       ierr = KSPSetFromOptions(eksp);CHKERRQ(ierr);
1236 
1237       ierr = KSPSetInitialGuessNonzero(eksp, PETSC_FALSE);CHKERRQ(ierr);
1238       ierr = KSPSetOperators(eksp, Amat, Amat);CHKERRQ(ierr);
1239       ierr = KSPSetComputeSingularValues(eksp,PETSC_TRUE);CHKERRQ(ierr);
1240 
1241       ierr = KSPGetPC(eksp, &epc);CHKERRQ(ierr);
1242       ierr = PCSetType(epc, PCJACOBI);CHKERRQ(ierr);  /* smoother in smoothed agg. */
1243 
1244       /* solve - keep stuff out of logging */
1245       ierr = PetscLogEventDeactivate(KSP_Solve);CHKERRQ(ierr);
1246       ierr = PetscLogEventDeactivate(PC_Apply);CHKERRQ(ierr);
1247       ierr = KSPSolve(eksp, bb, xx);CHKERRQ(ierr);
1248       ierr = PetscLogEventActivate(KSP_Solve);CHKERRQ(ierr);
1249       ierr = PetscLogEventActivate(PC_Apply);CHKERRQ(ierr);
1250 
1251       ierr = KSPComputeExtremeSingularValues(eksp, &emax, &emin);CHKERRQ(ierr);
1252       ierr = PetscInfo3(pc,"Smooth P0: max eigen=%e min=%e PC=%s\n",emax,emin,PCJACOBI);CHKERRQ(ierr);
1253       ierr = VecDestroy(&xx);CHKERRQ(ierr);
1254       ierr = VecDestroy(&bb);CHKERRQ(ierr);
1255       ierr = KSPDestroy(&eksp);CHKERRQ(ierr);
1256 
1257       if (pc_gamg->emax_id == -1) {
1258         ierr = PetscObjectComposedDataRegister(&pc_gamg->emax_id);CHKERRQ(ierr);
1259         if (pc_gamg->emax_id == -1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"pc_gamg->emax_id == -1");
1260       }
1261       ierr = PetscObjectComposedDataSetScalar((PetscObject)Amat, pc_gamg->emax_id, emax);CHKERRQ(ierr);
1262     }
1263 
1264     /* smooth P1 := (I - omega/lam D^{-1}A)P0 */
1265     ierr  = MatMatMult(Amat, Prol, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &tMat);CHKERRQ(ierr);
1266     ierr  = MatCreateVecs(Amat, &diag, 0);CHKERRQ(ierr);
1267     ierr  = MatGetDiagonal(Amat, diag);CHKERRQ(ierr); /* effectively PCJACOBI */
1268     ierr  = VecReciprocal(diag);CHKERRQ(ierr);
1269     ierr  = MatDiagonalScale(tMat, diag, 0);CHKERRQ(ierr);
1270     ierr  = VecDestroy(&diag);CHKERRQ(ierr);
1271     alpha = -1.4/emax;
1272     ierr  = MatAYPX(tMat, alpha, Prol, SUBSET_NONZERO_PATTERN);CHKERRQ(ierr);
1273     ierr  = MatDestroy(&Prol);CHKERRQ(ierr);
1274     Prol  = tMat;
1275 #if defined PETSC_GAMG_USE_LOG
1276     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET9],0,0,0,0);CHKERRQ(ierr);
1277 #endif
1278   }
1279   ierr = PetscLogEventEnd(PC_GAMGOptProlongator_AGG,0,0,0,0);CHKERRQ(ierr);
1280   *a_P = Prol;
1281   PetscFunctionReturn(0);
1282 }
1283 
1284 /* -------------------------------------------------------------------------- */
1285 /*
1286    PCCreateGAMG_AGG
1287 
1288   Input Parameter:
1289    . pc -
1290 */
1291 #undef __FUNCT__
1292 #define __FUNCT__ "PCCreateGAMG_AGG"
1293 PetscErrorCode  PCCreateGAMG_AGG(PC pc)
1294 {
1295   PetscErrorCode ierr;
1296   PC_MG          *mg      = (PC_MG*)pc->data;
1297   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
1298   PC_GAMG_AGG    *pc_gamg_agg;
1299 
1300   PetscFunctionBegin;
1301   /* create sub context for SA */
1302   ierr            = PetscNewLog(pc,&pc_gamg_agg);CHKERRQ(ierr);
1303   pc_gamg->subctx = pc_gamg_agg;
1304 
1305   pc_gamg->ops->setfromoptions = PCSetFromOptions_GAMG_AGG;
1306   pc_gamg->ops->destroy        = PCDestroy_GAMG_AGG;
1307   /* reset does not do anything; setup not virtual */
1308 
1309   /* set internal function pointers */
1310   pc_gamg->ops->graph             = PCGAMGGraph_AGG;
1311   pc_gamg->ops->coarsen           = PCGAMGCoarsen_AGG;
1312   pc_gamg->ops->prolongator       = PCGAMGProlongator_AGG;
1313   pc_gamg->ops->optprolongator    = PCGAMGOptProlongator_AGG;
1314   pc_gamg->ops->createdefaultdata = PCSetData_AGG;
1315   pc_gamg->ops->view              = PCView_GAMG_AGG;
1316 
1317   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",PCSetCoordinates_AGG);CHKERRQ(ierr);
1318   PetscFunctionReturn(0);
1319 }
1320