xref: /petsc/src/ksp/pc/impls/gamg/geo.c (revision 5adeb434db1cbecfaacaa61eb22541e5543bf6b2)
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 #if defined(PETSC_HAVE_TRIANGLE)
9 #define REAL PetscReal
10 #include <triangle.h>
11 #endif
12 
13 #include <petscblaslapack.h>
14 
15 /* Private context for the GAMG preconditioner */
16 typedef struct {
17   PetscInt lid;            /* local vertex index */
18   PetscInt degree;         /* vertex degree */
19 } GAMGNode;
20 
21 int petsc_geo_mg_compare(const void *a, const void *b)
22 {
23   return (((GAMGNode*)a)->degree - ((GAMGNode*)b)->degree);
24 }
25 
26 /* -------------------------------------------------------------------------- */
27 /*
28    PCSetCoordinates_GEO
29 
30    Input Parameter:
31    .  pc - the preconditioner context
32 */
33 #undef __FUNCT__
34 #define __FUNCT__ "PCSetCoordinates_GEO"
35 PetscErrorCode PCSetCoordinates_GEO(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
36 {
37   PC_MG          *mg      = (PC_MG*)pc->data;
38   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
39   PetscErrorCode ierr;
40   PetscInt       arrsz,bs,my0,kk,ii,nloc,Iend;
41   Mat            Amat = pc->pmat;
42 
43   PetscFunctionBegin;
44   PetscValidHeaderSpecific(Amat, MAT_CLASSID, 1);
45   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
46 
47   ierr = MatGetOwnershipRange(Amat, &my0, &Iend);CHKERRQ(ierr);
48   nloc = (Iend-my0)/bs;
49 
50   if (nloc!=a_nloc) SETERRQ2(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Stokes not supported nloc = %d %d.",a_nloc,nloc);
51   if ((Iend-my0)%bs!=0) SETERRQ1(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Bad local size %d.",nloc);
52 
53   pc_gamg->data_cell_rows = 1;
54   if (coords==0 && nloc > 0) SETERRQ(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Need coordinates for pc_gamg_type 'geo'.");
55   pc_gamg->data_cell_cols = ndm; /* coordinates */
56 
57   arrsz = nloc*pc_gamg->data_cell_rows*pc_gamg->data_cell_cols;
58 
59   /* create data - syntactic sugar that should be refactored at some point */
60   if (pc_gamg->data==0 || (pc_gamg->data_sz != arrsz)) {
61     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
62     ierr = PetscMalloc1(arrsz+1, &pc_gamg->data);CHKERRQ(ierr);
63   }
64   for (kk=0; kk<arrsz; kk++) pc_gamg->data[kk] = -999.;
65   pc_gamg->data[arrsz] = -99.;
66   /* copy data in - column oriented */
67   for (kk = 0; kk < nloc; kk++) {
68     for (ii = 0; ii < ndm; ii++) {
69       pc_gamg->data[ii*nloc + kk] =  coords[kk*ndm + ii];
70     }
71   }
72   if (pc_gamg->data[arrsz] != -99.) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"pc_gamg->data[arrsz %D] %g != -99.",arrsz,pc_gamg->data[arrsz]);
73   pc_gamg->data_sz = arrsz;
74   PetscFunctionReturn(0);
75 }
76 
77 /* -------------------------------------------------------------------------- */
78 /*
79    PCSetData_GEO
80 
81   Input Parameter:
82    . pc -
83 */
84 #undef __FUNCT__
85 #define __FUNCT__ "PCSetData_GEO"
86 PetscErrorCode PCSetData_GEO(PC pc, Mat m)
87 {
88   PetscFunctionBegin;
89   SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"GEO MG needs coordinates");
90 }
91 
92 /* -------------------------------------------------------------------------- */
93 /*
94    PCSetFromOptions_GEO
95 
96   Input Parameter:
97    . pc -
98 */
99 #undef __FUNCT__
100 #define __FUNCT__ "PCSetFromOptions_GEO"
101 PetscErrorCode PCSetFromOptions_GEO(PetscOptions *PetscOptionsObject,PC pc)
102 {
103   PetscErrorCode ierr;
104   PC_MG          *mg      = (PC_MG*)pc->data;
105   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
106 
107   PetscFunctionBegin;
108   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG-GEO options");CHKERRQ(ierr);
109   {
110     /* -pc_gamg_sa_nsmooths */
111     /* pc_gamg_sa->smooths = 0; */
112     /* ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths", */
113     /*                        "smoothing steps for smoothed aggregation, usually 1 (0)", */
114     /*                        "PCGAMGSetNSmooths_AGG", */
115     /*                        pc_gamg_sa->smooths, */
116     /*                        &pc_gamg_sa->smooths, */
117     /*                        &flag);  */
118     /* CHKERRQ(ierr); */
119   }
120   ierr = PetscOptionsTail();CHKERRQ(ierr);
121 
122   if (pc_gamg->verbose) {
123     PetscPrintf(PetscObjectComm((PetscObject)pc),"[%d]%s done\n",0,__FUNCT__);
124   }
125   PetscFunctionReturn(0);
126 }
127 
128 /* -------------------------------------------------------------------------- */
129 /*
130  triangulateAndFormProl
131 
132    Input Parameter:
133    . selected_2 - list of selected local ID, includes selected ghosts
134    . data_stride -
135    . coords[2*data_stride] - column vector of local coordinates w/ ghosts
136    . nselected_1 - selected IDs that go with base (1) graph
137    . clid_lid_1[nselected_1] - lids of selected (c) nodes   ???????????
138    . agg_lists_1 - list of aggregates
139    . crsGID[selected.size()] - global index for prolongation operator
140    . bs - block size
141   Output Parameter:
142    . a_Prol - prolongation operator
143    . a_worst_best - measure of worst missed fine vertex, 0 is no misses
144 */
145 #undef __FUNCT__
146 #define __FUNCT__ "triangulateAndFormProl"
147 static PetscErrorCode triangulateAndFormProl(IS  selected_2, /* list of selected local ID, includes selected ghosts */
148                                              const PetscInt data_stride,
149                                              const PetscReal coords[], /* column vector of local coordinates w/ ghosts */
150                                              const PetscInt nselected_1, /* list of selected local ID, includes selected ghosts */
151                                              const PetscInt clid_lid_1[],
152                                              const PetscCoarsenData *agg_lists_1, /* selected_1 vertices of aggregate unselected vertices */
153                                              const PetscInt crsGID[],
154                                              const PetscInt bs,
155                                              Mat a_Prol, /* prolongation operator (output) */
156                                              PetscReal *a_worst_best) /* measure of worst missed fine vertex, 0 is no misses */
157 {
158 #if defined(PETSC_HAVE_TRIANGLE)
159   PetscErrorCode       ierr;
160   PetscInt             jj,tid,tt,idx,nselected_2;
161   struct triangulateio in,mid;
162   const PetscInt       *selected_idx_2;
163   PetscMPIInt          rank;
164   PetscInt             Istart,Iend,nFineLoc,myFine0;
165   int                  kk,nPlotPts,sid;
166   MPI_Comm             comm;
167   PetscReal            tm;
168 
169   PetscFunctionBegin;
170   ierr = PetscObjectGetComm((PetscObject)a_Prol,&comm);CHKERRQ(ierr);
171   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
172   ierr = ISGetSize(selected_2, &nselected_2);CHKERRQ(ierr);
173   if (nselected_2 == 1 || nselected_2 == 2) { /* 0 happens on idle processors */
174     *a_worst_best = 100.0; /* this will cause a stop, but not globalized (should not happen) */
175   } else *a_worst_best = 0.0;
176   ierr = MPI_Allreduce(a_worst_best, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
177   if (tm > 0.0) {
178     *a_worst_best = 100.0;
179     PetscFunctionReturn(0);
180   }
181   ierr     = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
182   nFineLoc = (Iend-Istart)/bs; myFine0 = Istart/bs;
183   nPlotPts = nFineLoc; /* locals */
184   /* traingle */
185   /* Define input points - in*/
186   in.numberofpoints          = nselected_2;
187   in.numberofpointattributes = 0;
188   /* get nselected points */
189   ierr = PetscMalloc1(2*(nselected_2), &in.pointlist);CHKERRQ(ierr);
190   ierr = ISGetIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
191 
192   for (kk=0,sid=0; kk<nselected_2; kk++,sid += 2) {
193     PetscInt lid = selected_idx_2[kk];
194     in.pointlist[sid]   = coords[lid];
195     in.pointlist[sid+1] = coords[data_stride + lid];
196     if (lid>=nFineLoc) nPlotPts++;
197   }
198   if (sid != 2*nselected_2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != 2*nselected_2 %D",sid,nselected_2);
199 
200   in.numberofsegments      = 0;
201   in.numberofedges         = 0;
202   in.numberofholes         = 0;
203   in.numberofregions       = 0;
204   in.trianglelist          = 0;
205   in.segmentmarkerlist     = 0;
206   in.pointattributelist    = 0;
207   in.pointmarkerlist       = 0;
208   in.triangleattributelist = 0;
209   in.trianglearealist      = 0;
210   in.segmentlist           = 0;
211   in.holelist              = 0;
212   in.regionlist            = 0;
213   in.edgelist              = 0;
214   in.edgemarkerlist        = 0;
215   in.normlist              = 0;
216 
217   /* triangulate */
218   mid.pointlist = 0;            /* Not needed if -N switch used. */
219   /* Not needed if -N switch used or number of point attributes is zero: */
220   mid.pointattributelist = 0;
221   mid.pointmarkerlist    = 0; /* Not needed if -N or -B switch used. */
222   mid.trianglelist       = 0;    /* Not needed if -E switch used. */
223   /* Not needed if -E switch used or number of triangle attributes is zero: */
224   mid.triangleattributelist = 0;
225   mid.neighborlist          = 0; /* Needed only if -n switch used. */
226   /* Needed only if segments are output (-p or -c) and -P not used: */
227   mid.segmentlist = 0;
228   /* Needed only if segments are output (-p or -c) and -P and -B not used: */
229   mid.segmentmarkerlist = 0;
230   mid.edgelist          = 0;    /* Needed only if -e switch used. */
231   mid.edgemarkerlist    = 0; /* Needed if -e used and -B not used. */
232   mid.numberoftriangles = 0;
233 
234   /* Triangulate the points.  Switches are chosen to read and write a  */
235   /*   PSLG (p), preserve the convex hull (c), number everything from  */
236   /*   zero (z), assign a regional attribute to each element (A), and  */
237   /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
238   /*   neighbor list (n).                                            */
239   if (nselected_2 != 0) { /* inactive processor */
240     char args[] = "npczQ"; /* c is needed ? */
241     triangulate(args, &in, &mid, (struct triangulateio*) NULL);
242     /* output .poly files for 'showme' */
243     if (!PETSC_TRUE) {
244       static int level = 1;
245       FILE       *file; char fname[32];
246 
247       sprintf(fname,"C%d_%d.poly",level,rank); file = fopen(fname, "w");
248       /*First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)>*/
249       fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0);
250       /*Following lines: <vertex #> <x> <y> */
251       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid += 2) {
252         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
253       }
254       /*One line: <# of segments> <# of boundary markers (0 or 1)> */
255       fprintf(file, "%d  %d\n",0,0);
256       /*Following lines: <segment #> <endpoint> <endpoint> [boundary marker] */
257       /* One line: <# of holes> */
258       fprintf(file, "%d\n",0);
259       /* Following lines: <hole #> <x> <y> */
260       /* Optional line: <# of regional attributes and/or area constraints> */
261       /* Optional following lines: <region #> <x> <y> <attribute> <maximum area> */
262       fclose(file);
263 
264       /* elems */
265       sprintf(fname,"C%d_%d.ele",level,rank); file = fopen(fname, "w");
266       /* First line: <# of triangles> <nodes per triangle> <# of attributes> */
267       fprintf(file, "%d %d %d\n",mid.numberoftriangles,3,0);
268       /* Remaining lines: <triangle #> <node> <node> <node> ... [attributes] */
269       for (kk=0,sid=0; kk<mid.numberoftriangles; kk++,sid += 3) {
270         fprintf(file, "%d %d %d %d\n",kk,mid.trianglelist[sid],mid.trianglelist[sid+1],mid.trianglelist[sid+2]);
271       }
272       fclose(file);
273 
274       sprintf(fname,"C%d_%d.node",level,rank); file = fopen(fname, "w");
275       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
276       /* fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0); */
277       fprintf(file, "%d  %d  %d  %d\n",nPlotPts,2,0,0);
278       /*Following lines: <vertex #> <x> <y> */
279       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid+=2) {
280         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
281       }
282 
283       sid /= 2;
284       for (jj=0; jj<nFineLoc; jj++) {
285         PetscBool sel = PETSC_TRUE;
286         for (kk=0; kk<nselected_2 && sel; kk++) {
287           PetscInt lid = selected_idx_2[kk];
288           if (lid == jj) sel = PETSC_FALSE;
289         }
290         if (sel) fprintf(file, "%d %e %e\n",sid++,coords[jj],coords[data_stride + jj]);
291       }
292       fclose(file);
293       if (sid != nPlotPts) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != nPlotPts %D",sid,nPlotPts);
294       level++;
295     }
296   }
297 #if defined PETSC_GAMG_USE_LOG
298   ierr = PetscLogEventBegin(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
299 #endif
300   { /* form P - setup some maps */
301     PetscInt clid,mm,*nTri,*node_tri;
302 
303     ierr = PetscMalloc1(nselected_2, &node_tri);CHKERRQ(ierr);
304     ierr = PetscMalloc1(nselected_2, &nTri);CHKERRQ(ierr);
305 
306     /* need list of triangles on node */
307     for (kk=0; kk<nselected_2; kk++) nTri[kk] = 0;
308     for (tid=0,kk=0; tid<mid.numberoftriangles; tid++) {
309       for (jj=0; jj<3; jj++) {
310         PetscInt cid = mid.trianglelist[kk++];
311         if (nTri[cid] == 0) node_tri[cid] = tid;
312         nTri[cid]++;
313       }
314     }
315 #define EPS 1.e-12
316     /* find points and set prolongation */
317     for (mm = clid = 0; mm < nFineLoc; mm++) {
318       PetscBool ise;
319       ierr = PetscCDEmptyAt(agg_lists_1,mm,&ise);CHKERRQ(ierr);
320       if (!ise) {
321         const PetscInt lid = mm;
322         /* for (clid_iterator=0;clid_iterator<nselected_1;clid_iterator++) { */
323         PetscScalar  AA[3][3];
324         PetscBLASInt N=3,NRHS=1,LDA=3,IPIV[3],LDB=3,INFO;
325         PetscCDPos   pos;
326         ierr = PetscCDGetHeadPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
327         while (pos) {
328           PetscInt flid;
329           ierr = PetscLLNGetID(pos, &flid);CHKERRQ(ierr);
330           ierr = PetscCDGetNextPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
331 
332           if (flid < nFineLoc) {  /* could be a ghost */
333             PetscInt       bestTID = -1; PetscReal best_alpha = 1.e10;
334             const PetscInt fgid    = flid + myFine0;
335             /* compute shape function for gid */
336             const PetscReal fcoord[3] = {coords[flid],coords[data_stride+flid],1.0};
337             PetscBool       haveit    =PETSC_FALSE; PetscScalar alpha[3]; PetscInt clids[3];
338 
339             /* look for it */
340             for (tid = node_tri[clid], jj=0;
341                  jj < 5 && !haveit && tid != -1;
342                  jj++) {
343               for (tt=0; tt<3; tt++) {
344                 PetscInt cid2 = mid.trianglelist[3*tid + tt];
345                 PetscInt lid2 = selected_idx_2[cid2];
346                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
347                 clids[tt] = cid2; /* store for interp */
348               }
349 
350               for (tt=0; tt<3; tt++) alpha[tt] = (PetscScalar)fcoord[tt];
351 
352               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
353               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
354               {
355                 PetscBool have=PETSC_TRUE;  PetscReal lowest=1.e10;
356                 for (tt = 0, idx = 0; tt < 3; tt++) {
357                   if (PetscRealPart(alpha[tt]) > (1.0+EPS) || PetscRealPart(alpha[tt]) < -EPS) have = PETSC_FALSE;
358                   if (PetscRealPart(alpha[tt]) < lowest) {
359                     lowest = PetscRealPart(alpha[tt]);
360                     idx    = tt;
361                   }
362                 }
363                 haveit = have;
364               }
365               tid = mid.neighborlist[3*tid + idx];
366             }
367 
368             if (!haveit) {
369               /* brute force */
370               for (tid=0; tid<mid.numberoftriangles && !haveit; tid++) {
371                 for (tt=0; tt<3; tt++) {
372                   PetscInt cid2 = mid.trianglelist[3*tid + tt];
373                   PetscInt lid2 = selected_idx_2[cid2];
374                   AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
375                   clids[tt] = cid2; /* store for interp */
376                 }
377                 for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
378                 /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
379                 PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
380                 {
381                   PetscBool have=PETSC_TRUE;  PetscReal worst=0.0, v;
382                   for (tt=0; tt<3 && have; tt++) {
383                     if (PetscRealPart(alpha[tt]) > 1.0+EPS || PetscRealPart(alpha[tt]) < -EPS) have=PETSC_FALSE;
384                     if ((v=PetscAbs(PetscRealPart(alpha[tt])-0.5)) > worst) worst = v;
385                   }
386                   if (worst < best_alpha) {
387                     best_alpha = worst; bestTID = tid;
388                   }
389                   haveit = have;
390                 }
391               }
392             }
393             if (!haveit) {
394               if (best_alpha > *a_worst_best) *a_worst_best = best_alpha;
395               /* use best one */
396               for (tt=0; tt<3; tt++) {
397                 PetscInt cid2 = mid.trianglelist[3*bestTID + tt];
398                 PetscInt lid2 = selected_idx_2[cid2];
399                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
400                 clids[tt] = cid2; /* store for interp */
401               }
402               for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
403               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
404               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
405             }
406 
407             /* put in row of P */
408             for (idx=0; idx<3; idx++) {
409               PetscScalar shp = alpha[idx];
410               if (PetscAbs(PetscRealPart(shp)) > 1.e-6) {
411                 PetscInt cgid = crsGID[clids[idx]];
412                 PetscInt jj   = cgid*bs, ii = fgid*bs; /* need to gloalize */
413                 for (tt=0; tt < bs; tt++, ii++, jj++) {
414                   ierr = MatSetValues(a_Prol,1,&ii,1,&jj,&shp,INSERT_VALUES);CHKERRQ(ierr);
415                 }
416               }
417             }
418           }
419         } /* aggregates iterations */
420         clid++;
421       } /* a coarse agg */
422     } /* for all fine nodes */
423 
424     ierr = ISRestoreIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
425     ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
426     ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
427 
428     ierr = PetscFree(node_tri);CHKERRQ(ierr);
429     ierr = PetscFree(nTri);CHKERRQ(ierr);
430   }
431 #if defined PETSC_GAMG_USE_LOG
432   ierr = PetscLogEventEnd(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
433 #endif
434   free(mid.trianglelist);
435   free(mid.neighborlist);
436   ierr = PetscFree(in.pointlist);CHKERRQ(ierr);
437   PetscFunctionReturn(0);
438 #else
439   SETERRQ(PetscObjectComm((PetscObject)a_Prol),PETSC_ERR_PLIB,"configure with TRIANGLE to use geometric MG");
440 #endif
441 }
442 /* -------------------------------------------------------------------------- */
443 /*
444    getGIDsOnSquareGraph - square graph, get
445 
446    Input Parameter:
447    . nselected_1 - selected local indices (includes ghosts in input Gmat1)
448    . clid_lid_1 - [nselected_1] lids of selected nodes
449    . Gmat1 - graph that goes with 'selected_1'
450    Output Parameter:
451    . a_selected_2 - selected local indices (includes ghosts in output a_Gmat_2)
452    . a_Gmat_2 - graph that is squared of 'Gmat_1'
453    . a_crsGID[a_selected_2.size()] - map of global IDs of coarse grid nodes
454 */
455 #undef __FUNCT__
456 #define __FUNCT__ "getGIDsOnSquareGraph"
457 static PetscErrorCode getGIDsOnSquareGraph(const PetscInt nselected_1,const PetscInt clid_lid_1[],const Mat Gmat1,IS *a_selected_2,Mat *a_Gmat_2,PetscInt **a_crsGID)
458 {
459   PetscErrorCode ierr;
460   PetscMPIInt    size;
461   PetscInt       *crsGID, kk,my0,Iend,nloc;
462   MPI_Comm       comm;
463 
464   PetscFunctionBegin;
465   ierr = PetscObjectGetComm((PetscObject)Gmat1,&comm);CHKERRQ(ierr);
466   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
467   ierr = MatGetOwnershipRange(Gmat1,&my0,&Iend);CHKERRQ(ierr); /* AIJ */
468   nloc = Iend - my0; /* this does not change */
469 
470   if (size == 1) { /* not much to do in serial */
471     ierr = PetscMalloc1(nselected_1, &crsGID);CHKERRQ(ierr);
472     for (kk=0; kk<nselected_1; kk++) crsGID[kk] = kk;
473     *a_Gmat_2 = 0;
474     ierr      = ISCreateGeneral(PETSC_COMM_SELF,nselected_1,clid_lid_1,PETSC_COPY_VALUES,a_selected_2);CHKERRQ(ierr);
475   } else {
476     PetscInt    idx,num_fine_ghosts,num_crs_ghost,myCrs0;
477     Mat_MPIAIJ  *mpimat2;
478     Mat         Gmat2;
479     Vec         locState;
480     PetscScalar *cpcol_state;
481 
482     /* scan my coarse zero gid, set 'lid_state' with coarse GID */
483     kk = nselected_1;
484     MPI_Scan(&kk, &myCrs0, 1, MPIU_INT, MPIU_SUM, comm);
485     myCrs0 -= nselected_1;
486 
487     if (a_Gmat_2) { /* output */
488       /* grow graph to get wider set of selected vertices to cover fine grid, invalidates 'llist' */
489       ierr      = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
490       *a_Gmat_2 = Gmat2; /* output */
491     } else Gmat2 = Gmat1;  /* use local to get crsGIDs at least */
492     /* get coarse grid GIDS for selected (locals and ghosts) */
493     mpimat2 = (Mat_MPIAIJ*)Gmat2->data;
494     ierr    = MatCreateVecs(Gmat2, &locState, 0);CHKERRQ(ierr);
495     ierr    = VecSet(locState, (PetscScalar)(PetscReal)(-1));CHKERRQ(ierr); /* set with UNKNOWN state */
496     for (kk=0; kk<nselected_1; kk++) {
497       PetscInt    fgid = clid_lid_1[kk] + my0;
498       PetscScalar v    = (PetscScalar)(kk+myCrs0);
499       ierr = VecSetValues(locState, 1, &fgid, &v, INSERT_VALUES);CHKERRQ(ierr); /* set with PID */
500     }
501     ierr = VecAssemblyBegin(locState);CHKERRQ(ierr);
502     ierr = VecAssemblyEnd(locState);CHKERRQ(ierr);
503     ierr = VecScatterBegin(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
504     ierr =   VecScatterEnd(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
505     ierr = VecGetLocalSize(mpimat2->lvec, &num_fine_ghosts);CHKERRQ(ierr);
506     ierr = VecGetArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
507     for (kk=0,num_crs_ghost=0; kk<num_fine_ghosts; kk++) {
508       if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) num_crs_ghost++;
509     }
510     ierr = PetscMalloc1(nselected_1+num_crs_ghost, &crsGID);CHKERRQ(ierr); /* output */
511     {
512       PetscInt *selected_set;
513       ierr = PetscMalloc1(nselected_1+num_crs_ghost, &selected_set);CHKERRQ(ierr);
514       /* do ghost of 'crsGID' */
515       for (kk=0,idx=nselected_1; kk<num_fine_ghosts; kk++) {
516         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
517           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
518           selected_set[idx] = nloc + kk;
519           crsGID[idx++]     = cgid;
520         }
521       }
522       if (idx != (nselected_1+num_crs_ghost)) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"idx %D != (nselected_1 %D + num_crs_ghost %D)",idx,nselected_1,num_crs_ghost);
523       ierr = VecRestoreArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
524       /* do locals in 'crsGID' */
525       ierr = VecGetArray(locState, &cpcol_state);CHKERRQ(ierr);
526       for (kk=0,idx=0; kk<nloc; kk++) {
527         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
528           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
529           selected_set[idx] = kk;
530           crsGID[idx++]     = cgid;
531         }
532       }
533       if (idx != nselected_1) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"idx %D != nselected_1 %D",idx,nselected_1);
534       ierr = VecRestoreArray(locState, &cpcol_state);CHKERRQ(ierr);
535 
536       if (a_selected_2 != 0) { /* output */
537         ierr = ISCreateGeneral(PETSC_COMM_SELF,(nselected_1+num_crs_ghost),selected_set,PETSC_OWN_POINTER,a_selected_2);CHKERRQ(ierr);
538       } else {
539         ierr = PetscFree(selected_set);CHKERRQ(ierr);
540       }
541     }
542     ierr = VecDestroy(&locState);CHKERRQ(ierr);
543   }
544   *a_crsGID = crsGID; /* output */
545   PetscFunctionReturn(0);
546 }
547 
548 /* -------------------------------------------------------------------------- */
549 /*
550    PCGAMGGraph_GEO
551 
552   Input Parameter:
553    . pc - this
554    . Amat - matrix on this fine level
555   Output Parameter:
556    . a_Gmat
557 */
558 #undef __FUNCT__
559 #define __FUNCT__ "PCGAMGGraph_GEO"
560 PetscErrorCode PCGAMGGraph_GEO(PC pc,const Mat Amat,Mat *a_Gmat)
561 {
562   PetscErrorCode  ierr;
563   PC_MG           *mg      = (PC_MG*)pc->data;
564   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
565   const PetscInt  verbose  = pc_gamg->verbose;
566   const PetscReal vfilter  = pc_gamg->threshold;
567   MPI_Comm        comm;
568   Mat             Gmat;
569   PetscBool       set,flg,symm;
570 
571   PetscFunctionBegin;
572   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
573   ierr = PetscLogEventBegin(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
574 
575   ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr);
576   symm = (PetscBool)!(set && flg);
577 
578   ierr = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
579   ierr = PCGAMGFilterGraph(&Gmat, vfilter, symm, verbose);CHKERRQ(ierr);
580 
581   *a_Gmat = Gmat;
582   ierr = PetscLogEventEnd(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
583   PetscFunctionReturn(0);
584 }
585 
586 /* -------------------------------------------------------------------------- */
587 /*
588    PCGAMGCoarsen_GEO
589 
590   Input Parameter:
591    . a_pc - this
592    . a_Gmat - graph
593   Output Parameter:
594    . a_llist_parent - linked list from selected indices for data locality only
595 */
596 #undef __FUNCT__
597 #define __FUNCT__ "PCGAMGCoarsen_GEO"
598 PetscErrorCode PCGAMGCoarsen_GEO(PC a_pc,Mat *a_Gmat,PetscCoarsenData **a_llist_parent)
599 {
600   PetscErrorCode ierr;
601   PC_MG          *mg      = (PC_MG*)a_pc->data;
602   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
603   PetscInt       Istart,Iend,nloc,kk,Ii,ncols;
604   IS             perm;
605   GAMGNode       *gnodes;
606   PetscInt       *permute;
607   Mat            Gmat  = *a_Gmat;
608   MPI_Comm       comm;
609   MatCoarsen     crs;
610 
611   PetscFunctionBegin;
612   ierr = PetscObjectGetComm((PetscObject)a_pc,&comm);CHKERRQ(ierr);
613   ierr = PetscLogEventBegin(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
614   ierr = MatGetOwnershipRange(Gmat, &Istart, &Iend);CHKERRQ(ierr);
615   nloc = (Iend-Istart);
616 
617   /* create random permutation with sort for geo-mg */
618   ierr = PetscMalloc1(nloc, &gnodes);CHKERRQ(ierr);
619   ierr = PetscMalloc1(nloc, &permute);CHKERRQ(ierr);
620 
621   for (Ii=Istart; Ii<Iend; Ii++) { /* locals only? */
622     ierr = MatGetRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
623     {
624       PetscInt lid = Ii - Istart;
625       gnodes[lid].lid    = lid;
626       gnodes[lid].degree = ncols;
627     }
628     ierr = MatRestoreRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
629   }
630   /* randomize */
631   srand(1); /* make deterministic */
632   if (PETSC_TRUE) {
633     PetscBool *bIndexSet;
634     ierr = PetscMalloc1(nloc, &bIndexSet);CHKERRQ(ierr);
635     for (Ii = 0; Ii < nloc; Ii++) bIndexSet[Ii] = PETSC_FALSE;
636     for (Ii = 0; Ii < nloc; Ii++) {
637       PetscInt iSwapIndex = rand()%nloc;
638       if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
639         GAMGNode iTemp = gnodes[iSwapIndex];
640         gnodes[iSwapIndex]    = gnodes[Ii];
641         gnodes[Ii]            = iTemp;
642         bIndexSet[Ii]         = PETSC_TRUE;
643         bIndexSet[iSwapIndex] = PETSC_TRUE;
644       }
645     }
646     ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
647   }
648   /* only sort locals */
649   qsort(gnodes, nloc, sizeof(GAMGNode), petsc_geo_mg_compare);
650   /* create IS of permutation */
651   for (kk=0; kk<nloc; kk++) permute[kk] = gnodes[kk].lid; /* locals only */
652   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_OWN_POINTER, &perm);CHKERRQ(ierr);
653 
654   ierr = PetscFree(gnodes);CHKERRQ(ierr);
655 
656   /* get MIS aggs */
657 
658   ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
659   ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr);
660   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
661   ierr = MatCoarsenSetAdjacency(crs, Gmat);CHKERRQ(ierr);
662   ierr = MatCoarsenSetVerbose(crs, pc_gamg->verbose);CHKERRQ(ierr);
663   ierr = MatCoarsenSetStrictAggs(crs, PETSC_FALSE);CHKERRQ(ierr);
664   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
665   ierr = MatCoarsenGetData(crs, a_llist_parent);CHKERRQ(ierr);
666   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
667 
668   ierr = ISDestroy(&perm);CHKERRQ(ierr);
669   ierr = PetscLogEventEnd(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
670   PetscFunctionReturn(0);
671 }
672 
673 /* -------------------------------------------------------------------------- */
674 /*
675  PCGAMGProlongator_GEO
676 
677  Input Parameter:
678  . pc - this
679  . Amat - matrix on this fine level
680  . Graph - used to get ghost data for nodes in
681  . selected_1 - [nselected]
682  . agg_lists - [nselected]
683  Output Parameter:
684  . a_P_out - prolongation operator to the next level
685  */
686 #undef __FUNCT__
687 #define __FUNCT__ "PCGAMGProlongator_GEO"
688 PetscErrorCode PCGAMGProlongator_GEO(PC pc,const Mat Amat,const Mat Gmat,PetscCoarsenData *agg_lists,Mat *a_P_out)
689 {
690   PC_MG          *mg      = (PC_MG*)pc->data;
691   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
692   const PetscInt verbose  = pc_gamg->verbose;
693   const PetscInt dim      = pc_gamg->data_cell_cols, data_cols = pc_gamg->data_cell_cols;
694   PetscErrorCode ierr;
695   PetscInt       Istart,Iend,nloc,my0,jj,kk,ncols,nLocalSelected,bs,*clid_flid;
696   Mat            Prol;
697   PetscMPIInt    rank, size;
698   MPI_Comm       comm;
699   IS             selected_2,selected_1;
700   const PetscInt *selected_idx;
701 
702   PetscFunctionBegin;
703   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
704   ierr = PetscLogEventBegin(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
705   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
706   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
707   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
708   ierr = MatGetBlockSize(Amat, &bs);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) % bs %D",Iend,Istart,bs);
711 
712   /* get 'nLocalSelected' */
713   ierr = PetscCDGetMIS(agg_lists, &selected_1);CHKERRQ(ierr);
714   ierr = ISGetSize(selected_1, &jj);CHKERRQ(ierr);
715   ierr = PetscMalloc1(jj, &clid_flid);CHKERRQ(ierr);
716   ierr = ISGetIndices(selected_1, &selected_idx);CHKERRQ(ierr);
717   for (kk=0,nLocalSelected=0; kk<jj; kk++) {
718     PetscInt lid = selected_idx[kk];
719     if (lid<nloc) {
720       ierr = MatGetRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
721       if (ncols>1) clid_flid[nLocalSelected++] = lid; /* fiter out singletons */
722       ierr = MatRestoreRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
723     }
724   }
725   ierr = ISRestoreIndices(selected_1, &selected_idx);CHKERRQ(ierr);
726   ierr = ISDestroy(&selected_1);CHKERRQ(ierr); /* this is selected_1 in serial */
727 
728   /* create prolongator, create P matrix */
729   ierr = MatCreate(comm, &Prol);CHKERRQ(ierr);
730   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
731   ierr = MatSetBlockSizes(Prol, bs, bs);CHKERRQ(ierr);
732   ierr = MatSetType(Prol, MATAIJ);CHKERRQ(ierr);
733   ierr = MatSeqAIJSetPreallocation(Prol,3*data_cols,NULL);CHKERRQ(ierr);
734   ierr = MatMPIAIJSetPreallocation(Prol,3*data_cols,NULL,3*data_cols,NULL);CHKERRQ(ierr);
735   /* ierr = MatCreateAIJ(comm,  */
736   /*                      nloc*bs, nLocalSelected*bs, */
737   /*                      PETSC_DETERMINE, PETSC_DETERMINE, */
738   /*                      3*data_cols, NULL,  */
739   /*                      3*data_cols, NULL, */
740   /*                      &Prol); */
741   /* CHKERRQ(ierr); */
742 
743   /* can get all points "removed" - but not on geomg */
744   ierr =  MatGetSize(Prol, &kk, &jj);CHKERRQ(ierr);
745   if (jj==0) {
746     if (verbose) PetscPrintf(comm,"[%d]%s ERROE: no selected points on coarse grid\n",rank,__FUNCT__);
747     ierr = PetscFree(clid_flid);CHKERRQ(ierr);
748     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
749     *a_P_out = NULL;  /* out */
750     PetscFunctionReturn(0);
751   }
752 
753   {
754     PetscReal *coords;
755     PetscInt  data_stride;
756     PetscInt  *crsGID = NULL;
757     Mat       Gmat2;
758 
759     if (dim != data_cols) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"dim %D != data_cols %D",dim,data_cols);
760     /* grow ghost data for better coarse grid cover of fine grid */
761 #if defined PETSC_GAMG_USE_LOG
762     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
763 #endif
764     /* messy method, squares graph and gets some data */
765     ierr = getGIDsOnSquareGraph(nLocalSelected, clid_flid, Gmat, &selected_2, &Gmat2, &crsGID);CHKERRQ(ierr);
766     /* llist is now not valid wrt squared graph, but will work as iterator in 'triangulateAndFormProl' */
767 #if defined PETSC_GAMG_USE_LOG
768     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
769 #endif
770     /* create global vector of coorindates in 'coords' */
771     if (size > 1) {
772       ierr = PCGAMGGetDataWithGhosts(Gmat2, dim, pc_gamg->data, &data_stride, &coords);CHKERRQ(ierr);
773     } else {
774       coords      = (PetscReal*)pc_gamg->data;
775       data_stride = pc_gamg->data_sz/pc_gamg->data_cell_cols;
776     }
777     ierr = MatDestroy(&Gmat2);CHKERRQ(ierr);
778 
779     /* triangulate */
780     if (dim == 2) {
781       PetscReal metric,tm;
782 #if defined PETSC_GAMG_USE_LOG
783       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
784 #endif
785       ierr = triangulateAndFormProl(selected_2, data_stride, coords,nLocalSelected, clid_flid, agg_lists, crsGID, bs, Prol, &metric);CHKERRQ(ierr);
786 #if defined PETSC_GAMG_USE_LOG
787       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
788 #endif
789       ierr = PetscFree(crsGID);CHKERRQ(ierr);
790 
791       /* clean up and create coordinates for coarse grid (output) */
792       if (size > 1) ierr = PetscFree(coords);CHKERRQ(ierr);
793 
794       ierr = MPI_Allreduce(&metric, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
795       if (tm > 1.) { /* needs to be globalized - should not happen */
796         if (verbose) PetscPrintf(comm,"[%d]%s failed metric for coarse grid %e\n",rank,__FUNCT__,tm);
797         ierr = MatDestroy(&Prol);CHKERRQ(ierr);
798         Prol = NULL;
799       } else if (metric > .0) {
800         if (verbose) PetscPrintf(comm,"[%d]%s worst metric for coarse grid = %e\n",rank,__FUNCT__,metric);
801       }
802     } else SETERRQ(comm,PETSC_ERR_PLIB,"3D not implemented for 'geo' AMG");
803     { /* create next coords - output */
804       PetscReal *crs_crds;
805       ierr = PetscMalloc1(dim*nLocalSelected, &crs_crds);CHKERRQ(ierr);
806       for (kk=0; kk<nLocalSelected; kk++) { /* grab local select nodes to promote - output */
807         PetscInt lid = clid_flid[kk];
808         for (jj=0; jj<dim; jj++) crs_crds[jj*nLocalSelected + kk] = pc_gamg->data[jj*nloc + lid];
809       }
810 
811       ierr             = PetscFree(pc_gamg->data);CHKERRQ(ierr);
812       pc_gamg->data    = crs_crds; /* out */
813       pc_gamg->data_sz = dim*nLocalSelected;
814     }
815     ierr = ISDestroy(&selected_2);CHKERRQ(ierr);
816   }
817 
818   *a_P_out = Prol;  /* out */
819   ierr     = PetscFree(clid_flid);CHKERRQ(ierr);
820   ierr = PetscLogEventEnd(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
821   PetscFunctionReturn(0);
822 }
823 
824 #undef __FUNCT__
825 #define __FUNCT__ "PCDestroy_GAMG_GEO"
826 static PetscErrorCode PCDestroy_GAMG_GEO(PC pc)
827 {
828   PetscErrorCode ierr;
829 
830   PetscFunctionBegin;
831   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",NULL);CHKERRQ(ierr);
832   PetscFunctionReturn(0);
833 }
834 
835 /* -------------------------------------------------------------------------- */
836 /*
837  PCCreateGAMG_GEO
838 
839   Input Parameter:
840    . pc -
841 */
842 #undef __FUNCT__
843 #define __FUNCT__ "PCCreateGAMG_GEO"
844 PetscErrorCode  PCCreateGAMG_GEO(PC pc)
845 {
846   PetscErrorCode ierr;
847   PC_MG          *mg      = (PC_MG*)pc->data;
848   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
849 
850   PetscFunctionBegin;
851   pc_gamg->ops->setfromoptions = PCSetFromOptions_GEO;
852   pc_gamg->ops->destroy        = PCDestroy_GAMG_GEO;
853   /* reset does not do anything; setup not virtual */
854 
855   /* set internal function pointers */
856   pc_gamg->ops->graph             = PCGAMGGraph_GEO;
857   pc_gamg->ops->coarsen           = PCGAMGCoarsen_GEO;
858   pc_gamg->ops->prolongator       = PCGAMGProlongator_GEO;
859   pc_gamg->ops->optprolongator    = NULL;
860   pc_gamg->ops->createdefaultdata = PCSetData_GEO;
861 
862   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",PCSetCoordinates_GEO);CHKERRQ(ierr);
863   PetscFunctionReturn(0);
864 }
865