xref: /petsc/src/ksp/pc/impls/gamg/geo.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 #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 
105   PetscFunctionBegin;
106   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG-GEO options");CHKERRQ(ierr);
107   {
108     /* -pc_gamg_sa_nsmooths */
109     /* pc_gamg_sa->smooths = 0; */
110     /* ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths", */
111     /*                        "smoothing steps for smoothed aggregation, usually 1 (0)", */
112     /*                        "PCGAMGSetNSmooths_AGG", */
113     /*                        pc_gamg_sa->smooths, */
114     /*                        &pc_gamg_sa->smooths, */
115     /*                        &flag);  */
116     /* CHKERRQ(ierr); */
117   }
118   ierr = PetscOptionsTail();CHKERRQ(ierr);
119   PetscFunctionReturn(0);
120 }
121 
122 /* -------------------------------------------------------------------------- */
123 /*
124  triangulateAndFormProl
125 
126    Input Parameter:
127    . selected_2 - list of selected local ID, includes selected ghosts
128    . data_stride -
129    . coords[2*data_stride] - column vector of local coordinates w/ ghosts
130    . nselected_1 - selected IDs that go with base (1) graph includes selected ghosts
131    . clid_lid_1[nselected_1] - lids of selected (c) nodes   ???????????
132    . agg_lists_1 - list of aggregates selected_1 vertices of aggregate unselected vertices
133    . crsGID[selected.size()] - global index for prolongation operator
134    . bs - block size
135   Output Parameter:
136    . a_Prol - prolongation operator
137    . a_worst_best - measure of worst missed fine vertex, 0 is no misses
138 */
139 #undef __FUNCT__
140 #define __FUNCT__ "triangulateAndFormProl"
141 static PetscErrorCode triangulateAndFormProl(IS selected_2,PetscInt data_stride,PetscReal coords[],PetscInt nselected_1,const PetscInt clid_lid_1[],const PetscCoarsenData *agg_lists_1,
142                                              const PetscInt crsGID[],PetscInt bs,Mat a_Prol,PetscReal *a_worst_best)
143 {
144 #if defined(PETSC_HAVE_TRIANGLE)
145   PetscErrorCode       ierr;
146   PetscInt             jj,tid,tt,idx,nselected_2;
147   struct triangulateio in,mid;
148   const PetscInt       *selected_idx_2;
149   PetscMPIInt          rank;
150   PetscInt             Istart,Iend,nFineLoc,myFine0;
151   int                  kk,nPlotPts,sid;
152   MPI_Comm             comm;
153   PetscReal            tm;
154 
155   PetscFunctionBegin;
156   ierr = PetscObjectGetComm((PetscObject)a_Prol,&comm);CHKERRQ(ierr);
157   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
158   ierr = ISGetSize(selected_2, &nselected_2);CHKERRQ(ierr);
159   if (nselected_2 == 1 || nselected_2 == 2) { /* 0 happens on idle processors */
160     *a_worst_best = 100.0; /* this will cause a stop, but not globalized (should not happen) */
161   } else *a_worst_best = 0.0;
162   ierr = MPI_Allreduce(a_worst_best, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
163   if (tm > 0.0) {
164     *a_worst_best = 100.0;
165     PetscFunctionReturn(0);
166   }
167   ierr     = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
168   nFineLoc = (Iend-Istart)/bs; myFine0 = Istart/bs;
169   nPlotPts = nFineLoc; /* locals */
170   /* traingle */
171   /* Define input points - in*/
172   in.numberofpoints          = nselected_2;
173   in.numberofpointattributes = 0;
174   /* get nselected points */
175   ierr = PetscMalloc1(2*nselected_2, &in.pointlist);CHKERRQ(ierr);
176   ierr = ISGetIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
177 
178   for (kk=0,sid=0; kk<nselected_2; kk++,sid += 2) {
179     PetscInt lid = selected_idx_2[kk];
180     in.pointlist[sid]   = coords[lid];
181     in.pointlist[sid+1] = coords[data_stride + lid];
182     if (lid>=nFineLoc) nPlotPts++;
183   }
184   if (sid != 2*nselected_2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != 2*nselected_2 %D",sid,nselected_2);
185 
186   in.numberofsegments      = 0;
187   in.numberofedges         = 0;
188   in.numberofholes         = 0;
189   in.numberofregions       = 0;
190   in.trianglelist          = 0;
191   in.segmentmarkerlist     = 0;
192   in.pointattributelist    = 0;
193   in.pointmarkerlist       = 0;
194   in.triangleattributelist = 0;
195   in.trianglearealist      = 0;
196   in.segmentlist           = 0;
197   in.holelist              = 0;
198   in.regionlist            = 0;
199   in.edgelist              = 0;
200   in.edgemarkerlist        = 0;
201   in.normlist              = 0;
202 
203   /* triangulate */
204   mid.pointlist = 0;            /* Not needed if -N switch used. */
205   /* Not needed if -N switch used or number of point attributes is zero: */
206   mid.pointattributelist = 0;
207   mid.pointmarkerlist    = 0; /* Not needed if -N or -B switch used. */
208   mid.trianglelist       = 0;    /* Not needed if -E switch used. */
209   /* Not needed if -E switch used or number of triangle attributes is zero: */
210   mid.triangleattributelist = 0;
211   mid.neighborlist          = 0; /* Needed only if -n switch used. */
212   /* Needed only if segments are output (-p or -c) and -P not used: */
213   mid.segmentlist = 0;
214   /* Needed only if segments are output (-p or -c) and -P and -B not used: */
215   mid.segmentmarkerlist = 0;
216   mid.edgelist          = 0;    /* Needed only if -e switch used. */
217   mid.edgemarkerlist    = 0; /* Needed if -e used and -B not used. */
218   mid.numberoftriangles = 0;
219 
220   /* Triangulate the points.  Switches are chosen to read and write a  */
221   /*   PSLG (p), preserve the convex hull (c), number everything from  */
222   /*   zero (z), assign a regional attribute to each element (A), and  */
223   /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
224   /*   neighbor list (n).                                            */
225   if (nselected_2 != 0) { /* inactive processor */
226     char args[] = "npczQ"; /* c is needed ? */
227     triangulate(args, &in, &mid, (struct triangulateio*) NULL);
228     /* output .poly files for 'showme' */
229     if (!PETSC_TRUE) {
230       static int level = 1;
231       FILE       *file; char fname[32];
232 
233       sprintf(fname,"C%d_%d.poly",level,rank); file = fopen(fname, "w");
234       /*First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)>*/
235       fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0);
236       /*Following lines: <vertex #> <x> <y> */
237       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid += 2) {
238         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
239       }
240       /*One line: <# of segments> <# of boundary markers (0 or 1)> */
241       fprintf(file, "%d  %d\n",0,0);
242       /*Following lines: <segment #> <endpoint> <endpoint> [boundary marker] */
243       /* One line: <# of holes> */
244       fprintf(file, "%d\n",0);
245       /* Following lines: <hole #> <x> <y> */
246       /* Optional line: <# of regional attributes and/or area constraints> */
247       /* Optional following lines: <region #> <x> <y> <attribute> <maximum area> */
248       fclose(file);
249 
250       /* elems */
251       sprintf(fname,"C%d_%d.ele",level,rank); file = fopen(fname, "w");
252       /* First line: <# of triangles> <nodes per triangle> <# of attributes> */
253       fprintf(file, "%d %d %d\n",mid.numberoftriangles,3,0);
254       /* Remaining lines: <triangle #> <node> <node> <node> ... [attributes] */
255       for (kk=0,sid=0; kk<mid.numberoftriangles; kk++,sid += 3) {
256         fprintf(file, "%d %d %d %d\n",kk,mid.trianglelist[sid],mid.trianglelist[sid+1],mid.trianglelist[sid+2]);
257       }
258       fclose(file);
259 
260       sprintf(fname,"C%d_%d.node",level,rank); file = fopen(fname, "w");
261       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
262       /* fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0); */
263       fprintf(file, "%d  %d  %d  %d\n",nPlotPts,2,0,0);
264       /*Following lines: <vertex #> <x> <y> */
265       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid+=2) {
266         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
267       }
268 
269       sid /= 2;
270       for (jj=0; jj<nFineLoc; jj++) {
271         PetscBool sel = PETSC_TRUE;
272         for (kk=0; kk<nselected_2 && sel; kk++) {
273           PetscInt lid = selected_idx_2[kk];
274           if (lid == jj) sel = PETSC_FALSE;
275         }
276         if (sel) fprintf(file, "%d %e %e\n",sid++,coords[jj],coords[data_stride + jj]);
277       }
278       fclose(file);
279       if (sid != nPlotPts) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != nPlotPts %D",sid,nPlotPts);
280       level++;
281     }
282   }
283 #if defined PETSC_GAMG_USE_LOG
284   ierr = PetscLogEventBegin(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
285 #endif
286   { /* form P - setup some maps */
287     PetscInt clid,mm,*nTri,*node_tri;
288 
289     ierr = PetscMalloc2(nselected_2, &node_tri,nselected_2, &nTri);CHKERRQ(ierr);
290 
291     /* need list of triangles on node */
292     for (kk=0; kk<nselected_2; kk++) nTri[kk] = 0;
293     for (tid=0,kk=0; tid<mid.numberoftriangles; tid++) {
294       for (jj=0; jj<3; jj++) {
295         PetscInt cid = mid.trianglelist[kk++];
296         if (nTri[cid] == 0) node_tri[cid] = tid;
297         nTri[cid]++;
298       }
299     }
300 #define EPS 1.e-12
301     /* find points and set prolongation */
302     for (mm = clid = 0; mm < nFineLoc; mm++) {
303       PetscBool ise;
304       ierr = PetscCDEmptyAt(agg_lists_1,mm,&ise);CHKERRQ(ierr);
305       if (!ise) {
306         const PetscInt lid = mm;
307         /* for (clid_iterator=0;clid_iterator<nselected_1;clid_iterator++) { */
308         PetscScalar  AA[3][3];
309         PetscBLASInt N=3,NRHS=1,LDA=3,IPIV[3],LDB=3,INFO;
310         PetscCDPos   pos;
311         ierr = PetscCDGetHeadPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
312         while (pos) {
313           PetscInt flid;
314           ierr = PetscLLNGetID(pos, &flid);CHKERRQ(ierr);
315           ierr = PetscCDGetNextPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
316 
317           if (flid < nFineLoc) {  /* could be a ghost */
318             PetscInt       bestTID = -1; PetscReal best_alpha = 1.e10;
319             const PetscInt fgid    = flid + myFine0;
320             /* compute shape function for gid */
321             const PetscReal fcoord[3] = {coords[flid],coords[data_stride+flid],1.0};
322             PetscBool       haveit    =PETSC_FALSE; PetscScalar alpha[3]; PetscInt clids[3];
323 
324             /* look for it */
325             for (tid = node_tri[clid], jj=0;
326                  jj < 5 && !haveit && tid != -1;
327                  jj++) {
328               for (tt=0; tt<3; tt++) {
329                 PetscInt cid2 = mid.trianglelist[3*tid + tt];
330                 PetscInt lid2 = selected_idx_2[cid2];
331                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
332                 clids[tt] = cid2; /* store for interp */
333               }
334 
335               for (tt=0; tt<3; tt++) alpha[tt] = (PetscScalar)fcoord[tt];
336 
337               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
338               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
339               {
340                 PetscBool have=PETSC_TRUE;  PetscReal lowest=1.e10;
341                 for (tt = 0, idx = 0; tt < 3; tt++) {
342                   if (PetscRealPart(alpha[tt]) > (1.0+EPS) || PetscRealPart(alpha[tt]) < -EPS) have = PETSC_FALSE;
343                   if (PetscRealPart(alpha[tt]) < lowest) {
344                     lowest = PetscRealPart(alpha[tt]);
345                     idx    = tt;
346                   }
347                 }
348                 haveit = have;
349               }
350               tid = mid.neighborlist[3*tid + idx];
351             }
352 
353             if (!haveit) {
354               /* brute force */
355               for (tid=0; tid<mid.numberoftriangles && !haveit; tid++) {
356                 for (tt=0; tt<3; tt++) {
357                   PetscInt cid2 = mid.trianglelist[3*tid + tt];
358                   PetscInt lid2 = selected_idx_2[cid2];
359                   AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
360                   clids[tt] = cid2; /* store for interp */
361                 }
362                 for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
363                 /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
364                 PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
365                 {
366                   PetscBool have=PETSC_TRUE;  PetscReal worst=0.0, v;
367                   for (tt=0; tt<3 && have; tt++) {
368                     if (PetscRealPart(alpha[tt]) > 1.0+EPS || PetscRealPart(alpha[tt]) < -EPS) have=PETSC_FALSE;
369                     if ((v=PetscAbs(PetscRealPart(alpha[tt])-0.5)) > worst) worst = v;
370                   }
371                   if (worst < best_alpha) {
372                     best_alpha = worst; bestTID = tid;
373                   }
374                   haveit = have;
375                 }
376               }
377             }
378             if (!haveit) {
379               if (best_alpha > *a_worst_best) *a_worst_best = best_alpha;
380               /* use best one */
381               for (tt=0; tt<3; tt++) {
382                 PetscInt cid2 = mid.trianglelist[3*bestTID + tt];
383                 PetscInt lid2 = selected_idx_2[cid2];
384                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
385                 clids[tt] = cid2; /* store for interp */
386               }
387               for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
388               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
389               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
390             }
391 
392             /* put in row of P */
393             for (idx=0; idx<3; idx++) {
394               PetscScalar shp = alpha[idx];
395               if (PetscAbs(PetscRealPart(shp)) > 1.e-6) {
396                 PetscInt cgid = crsGID[clids[idx]];
397                 PetscInt jj   = cgid*bs, ii = fgid*bs; /* need to gloalize */
398                 for (tt=0; tt < bs; tt++, ii++, jj++) {
399                   ierr = MatSetValues(a_Prol,1,&ii,1,&jj,&shp,INSERT_VALUES);CHKERRQ(ierr);
400                 }
401               }
402             }
403           }
404         } /* aggregates iterations */
405         clid++;
406       } /* a coarse agg */
407     } /* for all fine nodes */
408 
409     ierr = ISRestoreIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
410     ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
411     ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
412 
413     ierr = PetscFree2(node_tri,nTri);CHKERRQ(ierr);
414   }
415 #if defined PETSC_GAMG_USE_LOG
416   ierr = PetscLogEventEnd(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
417 #endif
418   free(mid.trianglelist);
419   free(mid.neighborlist);
420   ierr = PetscFree(in.pointlist);CHKERRQ(ierr);
421   PetscFunctionReturn(0);
422 #else
423   SETERRQ(PetscObjectComm((PetscObject)a_Prol),PETSC_ERR_PLIB,"configure with TRIANGLE to use geometric MG");
424 #endif
425 }
426 /* -------------------------------------------------------------------------- */
427 /*
428    getGIDsOnSquareGraph - square graph, get
429 
430    Input Parameter:
431    . nselected_1 - selected local indices (includes ghosts in input Gmat1)
432    . clid_lid_1 - [nselected_1] lids of selected nodes
433    . Gmat1 - graph that goes with 'selected_1'
434    Output Parameter:
435    . a_selected_2 - selected local indices (includes ghosts in output a_Gmat_2)
436    . a_Gmat_2 - graph that is squared of 'Gmat_1'
437    . a_crsGID[a_selected_2.size()] - map of global IDs of coarse grid nodes
438 */
439 #undef __FUNCT__
440 #define __FUNCT__ "getGIDsOnSquareGraph"
441 static PetscErrorCode getGIDsOnSquareGraph(PetscInt nselected_1,const PetscInt clid_lid_1[],const Mat Gmat1,IS *a_selected_2,Mat *a_Gmat_2,PetscInt **a_crsGID)
442 {
443   PetscErrorCode ierr;
444   PetscMPIInt    size;
445   PetscInt       *crsGID, kk,my0,Iend,nloc;
446   MPI_Comm       comm;
447 
448   PetscFunctionBegin;
449   ierr = PetscObjectGetComm((PetscObject)Gmat1,&comm);CHKERRQ(ierr);
450   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
451   ierr = MatGetOwnershipRange(Gmat1,&my0,&Iend);CHKERRQ(ierr); /* AIJ */
452   nloc = Iend - my0; /* this does not change */
453 
454   if (size == 1) { /* not much to do in serial */
455     ierr = PetscMalloc1(nselected_1, &crsGID);CHKERRQ(ierr);
456     for (kk=0; kk<nselected_1; kk++) crsGID[kk] = kk;
457     *a_Gmat_2 = 0;
458     ierr      = ISCreateGeneral(PETSC_COMM_SELF,nselected_1,clid_lid_1,PETSC_COPY_VALUES,a_selected_2);CHKERRQ(ierr);
459   } else {
460     PetscInt    idx,num_fine_ghosts,num_crs_ghost,myCrs0;
461     Mat_MPIAIJ  *mpimat2;
462     Mat         Gmat2;
463     Vec         locState;
464     PetscScalar *cpcol_state;
465 
466     /* scan my coarse zero gid, set 'lid_state' with coarse GID */
467     kk = nselected_1;
468     ierr = MPI_Scan(&kk, &myCrs0, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
469     myCrs0 -= nselected_1;
470 
471     if (a_Gmat_2) { /* output */
472       /* grow graph to get wider set of selected vertices to cover fine grid, invalidates 'llist' */
473       ierr      = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
474       *a_Gmat_2 = Gmat2; /* output */
475     } else Gmat2 = Gmat1;  /* use local to get crsGIDs at least */
476     /* get coarse grid GIDS for selected (locals and ghosts) */
477     mpimat2 = (Mat_MPIAIJ*)Gmat2->data;
478     ierr    = MatCreateVecs(Gmat2, &locState, 0);CHKERRQ(ierr);
479     ierr    = VecSet(locState, (PetscScalar)(PetscReal)(-1));CHKERRQ(ierr); /* set with UNKNOWN state */
480     for (kk=0; kk<nselected_1; kk++) {
481       PetscInt    fgid = clid_lid_1[kk] + my0;
482       PetscScalar v    = (PetscScalar)(kk+myCrs0);
483       ierr = VecSetValues(locState, 1, &fgid, &v, INSERT_VALUES);CHKERRQ(ierr); /* set with PID */
484     }
485     ierr = VecAssemblyBegin(locState);CHKERRQ(ierr);
486     ierr = VecAssemblyEnd(locState);CHKERRQ(ierr);
487     ierr = VecScatterBegin(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
488     ierr =   VecScatterEnd(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
489     ierr = VecGetLocalSize(mpimat2->lvec, &num_fine_ghosts);CHKERRQ(ierr);
490     ierr = VecGetArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
491     for (kk=0,num_crs_ghost=0; kk<num_fine_ghosts; kk++) {
492       if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) num_crs_ghost++;
493     }
494     ierr = PetscMalloc1(nselected_1+num_crs_ghost, &crsGID);CHKERRQ(ierr); /* output */
495     {
496       PetscInt *selected_set;
497       ierr = PetscMalloc1(nselected_1+num_crs_ghost, &selected_set);CHKERRQ(ierr);
498       /* do ghost of 'crsGID' */
499       for (kk=0,idx=nselected_1; kk<num_fine_ghosts; kk++) {
500         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
501           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
502           selected_set[idx] = nloc + kk;
503           crsGID[idx++]     = cgid;
504         }
505       }
506       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);
507       ierr = VecRestoreArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
508       /* do locals in 'crsGID' */
509       ierr = VecGetArray(locState, &cpcol_state);CHKERRQ(ierr);
510       for (kk=0,idx=0; kk<nloc; kk++) {
511         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
512           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
513           selected_set[idx] = kk;
514           crsGID[idx++]     = cgid;
515         }
516       }
517       if (idx != nselected_1) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"idx %D != nselected_1 %D",idx,nselected_1);
518       ierr = VecRestoreArray(locState, &cpcol_state);CHKERRQ(ierr);
519 
520       if (a_selected_2 != 0) { /* output */
521         ierr = ISCreateGeneral(PETSC_COMM_SELF,(nselected_1+num_crs_ghost),selected_set,PETSC_OWN_POINTER,a_selected_2);CHKERRQ(ierr);
522       } else {
523         ierr = PetscFree(selected_set);CHKERRQ(ierr);
524       }
525     }
526     ierr = VecDestroy(&locState);CHKERRQ(ierr);
527   }
528   *a_crsGID = crsGID; /* output */
529   PetscFunctionReturn(0);
530 }
531 
532 /* -------------------------------------------------------------------------- */
533 /*
534    PCGAMGGraph_GEO
535 
536   Input Parameter:
537    . pc - this
538    . Amat - matrix on this fine level
539   Output Parameter:
540    . a_Gmat
541 */
542 #undef __FUNCT__
543 #define __FUNCT__ "PCGAMGGraph_GEO"
544 PetscErrorCode PCGAMGGraph_GEO(PC pc,Mat Amat,Mat *a_Gmat)
545 {
546   PetscErrorCode  ierr;
547   PC_MG           *mg      = (PC_MG*)pc->data;
548   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
549   const PetscReal vfilter  = pc_gamg->threshold;
550   MPI_Comm        comm;
551   Mat             Gmat;
552   PetscBool       set,flg,symm;
553 
554   PetscFunctionBegin;
555   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
556   ierr = PetscLogEventBegin(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
557 
558   ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr);
559   symm = (PetscBool)!(set && flg);
560 
561   ierr = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
562   ierr = PCGAMGFilterGraph(&Gmat, vfilter, symm);CHKERRQ(ierr);
563 
564   *a_Gmat = Gmat;
565   ierr = PetscLogEventEnd(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
566   PetscFunctionReturn(0);
567 }
568 
569 /* -------------------------------------------------------------------------- */
570 /*
571    PCGAMGCoarsen_GEO
572 
573   Input Parameter:
574    . a_pc - this
575    . a_Gmat - graph
576   Output Parameter:
577    . a_llist_parent - linked list from selected indices for data locality only
578 */
579 #undef __FUNCT__
580 #define __FUNCT__ "PCGAMGCoarsen_GEO"
581 PetscErrorCode PCGAMGCoarsen_GEO(PC a_pc,Mat *a_Gmat,PetscCoarsenData **a_llist_parent)
582 {
583   PetscErrorCode ierr;
584   PetscInt       Istart,Iend,nloc,kk,Ii,ncols;
585   IS             perm;
586   GAMGNode       *gnodes;
587   PetscInt       *permute;
588   Mat            Gmat  = *a_Gmat;
589   MPI_Comm       comm;
590   MatCoarsen     crs;
591 
592   PetscFunctionBegin;
593   ierr = PetscObjectGetComm((PetscObject)a_pc,&comm);CHKERRQ(ierr);
594   ierr = PetscLogEventBegin(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
595   ierr = MatGetOwnershipRange(Gmat, &Istart, &Iend);CHKERRQ(ierr);
596   nloc = (Iend-Istart);
597 
598   /* create random permutation with sort for geo-mg */
599   ierr = PetscMalloc1(nloc, &gnodes);CHKERRQ(ierr);
600   ierr = PetscMalloc1(nloc, &permute);CHKERRQ(ierr);
601 
602   for (Ii=Istart; Ii<Iend; Ii++) { /* locals only? */
603     ierr = MatGetRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
604     {
605       PetscInt lid = Ii - Istart;
606       gnodes[lid].lid    = lid;
607       gnodes[lid].degree = ncols;
608     }
609     ierr = MatRestoreRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
610   }
611   /* randomize */
612   srand(1); /* make deterministic */
613   if (PETSC_TRUE) {
614     PetscBool *bIndexSet;
615     ierr = PetscMalloc1(nloc, &bIndexSet);CHKERRQ(ierr);
616     for (Ii = 0; Ii < nloc; Ii++) bIndexSet[Ii] = PETSC_FALSE;
617     for (Ii = 0; Ii < nloc; Ii++) {
618       PetscInt iSwapIndex = rand()%nloc;
619       if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
620         GAMGNode iTemp = gnodes[iSwapIndex];
621         gnodes[iSwapIndex]    = gnodes[Ii];
622         gnodes[Ii]            = iTemp;
623         bIndexSet[Ii]         = PETSC_TRUE;
624         bIndexSet[iSwapIndex] = PETSC_TRUE;
625       }
626     }
627     ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
628   }
629   /* only sort locals */
630   qsort(gnodes, nloc, sizeof(GAMGNode), petsc_geo_mg_compare);
631   /* create IS of permutation */
632   for (kk=0; kk<nloc; kk++) permute[kk] = gnodes[kk].lid; /* locals only */
633   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_OWN_POINTER, &perm);CHKERRQ(ierr);
634 
635   ierr = PetscFree(gnodes);CHKERRQ(ierr);
636 
637   /* get MIS aggs */
638 
639   ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
640   ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr);
641   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
642   ierr = MatCoarsenSetAdjacency(crs, Gmat);CHKERRQ(ierr);
643   ierr = MatCoarsenSetStrictAggs(crs, PETSC_FALSE);CHKERRQ(ierr);
644   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
645   ierr = MatCoarsenGetData(crs, a_llist_parent);CHKERRQ(ierr);
646   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
647 
648   ierr = ISDestroy(&perm);CHKERRQ(ierr);
649   ierr = PetscLogEventEnd(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
650   PetscFunctionReturn(0);
651 }
652 
653 /* -------------------------------------------------------------------------- */
654 /*
655  PCGAMGProlongator_GEO
656 
657  Input Parameter:
658  . pc - this
659  . Amat - matrix on this fine level
660  . Graph - used to get ghost data for nodes in
661  . selected_1 - [nselected]
662  . agg_lists - [nselected]
663  Output Parameter:
664  . a_P_out - prolongation operator to the next level
665  */
666 #undef __FUNCT__
667 #define __FUNCT__ "PCGAMGProlongator_GEO"
668 PetscErrorCode PCGAMGProlongator_GEO(PC pc,Mat Amat,Mat Gmat,PetscCoarsenData *agg_lists,Mat *a_P_out)
669 {
670   PC_MG          *mg      = (PC_MG*)pc->data;
671   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
672   const PetscInt dim      = pc_gamg->data_cell_cols, data_cols = pc_gamg->data_cell_cols;
673   PetscErrorCode ierr;
674   PetscInt       Istart,Iend,nloc,my0,jj,kk,ncols,nLocalSelected,bs,*clid_flid;
675   Mat            Prol;
676   PetscMPIInt    rank, size;
677   MPI_Comm       comm;
678   IS             selected_2,selected_1;
679   const PetscInt *selected_idx;
680   MatType        mtype;
681 
682   PetscFunctionBegin;
683   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
684   ierr = PetscLogEventBegin(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
685   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
686   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
687   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
688   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
689   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
690   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(Iend %D - Istart %D) % bs %D",Iend,Istart,bs);
691 
692   /* get 'nLocalSelected' */
693   ierr = PetscCDGetMIS(agg_lists, &selected_1);CHKERRQ(ierr);
694   ierr = ISGetSize(selected_1, &jj);CHKERRQ(ierr);
695   ierr = PetscMalloc1(jj, &clid_flid);CHKERRQ(ierr);
696   ierr = ISGetIndices(selected_1, &selected_idx);CHKERRQ(ierr);
697   for (kk=0,nLocalSelected=0; kk<jj; kk++) {
698     PetscInt lid = selected_idx[kk];
699     if (lid<nloc) {
700       ierr = MatGetRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
701       if (ncols>1) clid_flid[nLocalSelected++] = lid; /* fiter out singletons */
702       ierr = MatRestoreRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
703     }
704   }
705   ierr = ISRestoreIndices(selected_1, &selected_idx);CHKERRQ(ierr);
706   ierr = ISDestroy(&selected_1);CHKERRQ(ierr); /* this is selected_1 in serial */
707 
708   /* create prolongator  matrix */
709   ierr = MatGetType(Amat,&mtype);CHKERRQ(ierr);
710   ierr = MatCreate(comm, &Prol);CHKERRQ(ierr);
711   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
712   ierr = MatSetBlockSizes(Prol, bs, bs);CHKERRQ(ierr);
713   ierr = MatSetType(Prol, mtype);CHKERRQ(ierr);
714   ierr = MatSeqAIJSetPreallocation(Prol,3*data_cols,NULL);CHKERRQ(ierr);
715   ierr = MatMPIAIJSetPreallocation(Prol,3*data_cols,NULL,3*data_cols,NULL);CHKERRQ(ierr);
716 
717   /* can get all points "removed" - but not on geomg */
718   ierr =  MatGetSize(Prol, &kk, &jj);CHKERRQ(ierr);
719   if (jj==0) {
720     ierr = PetscInfo(pc,"ERROE: no selected points on coarse grid\n");CHKERRQ(ierr);
721     ierr = PetscFree(clid_flid);CHKERRQ(ierr);
722     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
723     *a_P_out = NULL;  /* out */
724     PetscFunctionReturn(0);
725   }
726 
727   {
728     PetscReal *coords;
729     PetscInt  data_stride;
730     PetscInt  *crsGID = NULL;
731     Mat       Gmat2;
732 
733     if (dim != data_cols) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"dim %D != data_cols %D",dim,data_cols);
734     /* grow ghost data for better coarse grid cover of fine grid */
735 #if defined PETSC_GAMG_USE_LOG
736     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
737 #endif
738     /* messy method, squares graph and gets some data */
739     ierr = getGIDsOnSquareGraph(nLocalSelected, clid_flid, Gmat, &selected_2, &Gmat2, &crsGID);CHKERRQ(ierr);
740     /* llist is now not valid wrt squared graph, but will work as iterator in 'triangulateAndFormProl' */
741 #if defined PETSC_GAMG_USE_LOG
742     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
743 #endif
744     /* create global vector of coorindates in 'coords' */
745     if (size > 1) {
746       ierr = PCGAMGGetDataWithGhosts(Gmat2, dim, pc_gamg->data, &data_stride, &coords);CHKERRQ(ierr);
747     } else {
748       coords      = (PetscReal*)pc_gamg->data;
749       data_stride = pc_gamg->data_sz/pc_gamg->data_cell_cols;
750     }
751     ierr = MatDestroy(&Gmat2);CHKERRQ(ierr);
752 
753     /* triangulate */
754     if (dim == 2) {
755       PetscReal metric,tm;
756 #if defined PETSC_GAMG_USE_LOG
757       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
758 #endif
759       ierr = triangulateAndFormProl(selected_2, data_stride, coords,nLocalSelected, clid_flid, agg_lists, crsGID, bs, Prol, &metric);CHKERRQ(ierr);
760 #if defined PETSC_GAMG_USE_LOG
761       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
762 #endif
763       ierr = PetscFree(crsGID);CHKERRQ(ierr);
764 
765       /* clean up and create coordinates for coarse grid (output) */
766       if (size > 1) ierr = PetscFree(coords);CHKERRQ(ierr);
767 
768       ierr = MPI_Allreduce(&metric, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
769       if (tm > 1.) { /* needs to be globalized - should not happen */
770         ierr = PetscInfo1(pc," failed metric for coarse grid %e\n",(double)tm);CHKERRQ(ierr);
771         ierr = MatDestroy(&Prol);CHKERRQ(ierr);
772       } else if (metric > .0) {
773         ierr = PetscInfo1(pc,"worst metric for coarse grid = %e\n",(double)metric);CHKERRQ(ierr);
774       }
775     } else SETERRQ(comm,PETSC_ERR_PLIB,"3D not implemented for 'geo' AMG");
776     { /* create next coords - output */
777       PetscReal *crs_crds;
778       ierr = PetscMalloc1(dim*nLocalSelected, &crs_crds);CHKERRQ(ierr);
779       for (kk=0; kk<nLocalSelected; kk++) { /* grab local select nodes to promote - output */
780         PetscInt lid = clid_flid[kk];
781         for (jj=0; jj<dim; jj++) crs_crds[jj*nLocalSelected + kk] = pc_gamg->data[jj*nloc + lid];
782       }
783 
784       ierr             = PetscFree(pc_gamg->data);CHKERRQ(ierr);
785       pc_gamg->data    = crs_crds; /* out */
786       pc_gamg->data_sz = dim*nLocalSelected;
787     }
788     ierr = ISDestroy(&selected_2);CHKERRQ(ierr);
789   }
790 
791   *a_P_out = Prol;  /* out */
792   ierr     = PetscFree(clid_flid);CHKERRQ(ierr);
793   ierr = PetscLogEventEnd(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
794   PetscFunctionReturn(0);
795 }
796 
797 #undef __FUNCT__
798 #define __FUNCT__ "PCDestroy_GAMG_GEO"
799 static PetscErrorCode PCDestroy_GAMG_GEO(PC pc)
800 {
801   PetscErrorCode ierr;
802 
803   PetscFunctionBegin;
804   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",NULL);CHKERRQ(ierr);
805   PetscFunctionReturn(0);
806 }
807 
808 /* -------------------------------------------------------------------------- */
809 /*
810  PCCreateGAMG_GEO
811 
812   Input Parameter:
813    . pc -
814 */
815 #undef __FUNCT__
816 #define __FUNCT__ "PCCreateGAMG_GEO"
817 PetscErrorCode  PCCreateGAMG_GEO(PC pc)
818 {
819   PetscErrorCode ierr;
820   PC_MG          *mg      = (PC_MG*)pc->data;
821   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
822 
823   PetscFunctionBegin;
824   pc_gamg->ops->setfromoptions = PCSetFromOptions_GEO;
825   pc_gamg->ops->destroy        = PCDestroy_GAMG_GEO;
826   /* reset does not do anything; setup not virtual */
827 
828   /* set internal function pointers */
829   pc_gamg->ops->graph             = PCGAMGGraph_GEO;
830   pc_gamg->ops->coarsen           = PCGAMGCoarsen_GEO;
831   pc_gamg->ops->prolongator       = PCGAMGProlongator_GEO;
832   pc_gamg->ops->optprolongator    = NULL;
833   pc_gamg->ops->createdefaultdata = PCSetData_GEO;
834 
835   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",PCSetCoordinates_GEO);CHKERRQ(ierr);
836   PetscFunctionReturn(0);
837 }
838