Actual source code: geo.c

  1: /*
  2:  GAMG geometric-algebraic multigrid PC - Mark Adams 2011
  3:  */

  5: #include <../src/ksp/pc/impls/gamg/gamg.h>

  7: #if defined(PETSC_HAVE_TRIANGLE)
  8:   #if !defined(ANSI_DECLARATORS)
  9:     #define ANSI_DECLARATORS
 10:   #endif
 11:   #include <triangle.h>
 12: #endif

 14: #include <petscblaslapack.h>

 16: /* Private context for the GAMG preconditioner */
 17: typedef struct {
 18:   PetscInt lid;    /* local vertex index */
 19:   PetscInt degree; /* vertex degree */
 20: } GAMGNode;

 22: static inline int petsc_geo_mg_compare(const void *a, const void *b)
 23: {
 24:   return (int)(((GAMGNode *)a)->degree - ((GAMGNode *)b)->degree);
 25: }

 27: // PetscClangLinter pragma disable: -fdoc-sowing-chars
 28: /*
 29:    PCSetCoordinates_GEO

 31:    Input Parameter:
 32:    .  pc - the preconditioner context
 33: */
 34: static PetscErrorCode PCSetCoordinates_GEO(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
 35: {
 36:   PC_MG   *mg      = (PC_MG *)pc->data;
 37:   PC_GAMG *pc_gamg = (PC_GAMG *)mg->innerctx;
 38:   PetscInt arrsz, bs, my0, kk, ii, nloc, Iend, aloc;
 39:   Mat      Amat = pc->pmat;

 41:   PetscFunctionBegin;
 43:   PetscCall(MatGetBlockSize(Amat, &bs));
 44:   PetscCall(MatGetOwnershipRange(Amat, &my0, &Iend));
 45:   aloc = (Iend - my0);
 46:   nloc = (Iend - my0) / bs;

 48:   PetscCheck(nloc == a_nloc || aloc == a_nloc, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Number of local blocks %" PetscInt_FMT " must be %" PetscInt_FMT " or %" PetscInt_FMT ".", a_nloc, nloc, aloc);

 50:   pc_gamg->data_cell_rows = 1;
 51:   PetscCheck(coords || (nloc <= 0), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Need coordinates for pc_gamg_type 'geo'.");
 52:   pc_gamg->data_cell_cols = ndm; /* coordinates */

 54:   arrsz = nloc * pc_gamg->data_cell_rows * pc_gamg->data_cell_cols;

 56:   /* create data - syntactic sugar that should be refactored at some point */
 57:   if (!pc_gamg->data || (pc_gamg->data_sz != arrsz)) {
 58:     PetscCall(PetscFree(pc_gamg->data));
 59:     PetscCall(PetscMalloc1(arrsz + 1, &pc_gamg->data));
 60:   }
 61:   for (kk = 0; kk < arrsz; kk++) pc_gamg->data[kk] = -999.;
 62:   pc_gamg->data[arrsz] = -99.;
 63:   /* copy data in - column-oriented */
 64:   if (nloc == a_nloc) {
 65:     for (kk = 0; kk < nloc; kk++) {
 66:       for (ii = 0; ii < ndm; ii++) pc_gamg->data[ii * nloc + kk] = coords[kk * ndm + ii];
 67:     }
 68:   } else { /* assumes the coordinates are blocked */
 69:     for (kk = 0; kk < nloc; kk++) {
 70:       for (ii = 0; ii < ndm; ii++) pc_gamg->data[ii * nloc + kk] = coords[bs * kk * ndm + ii];
 71:     }
 72:   }
 73:   PetscCheck(pc_gamg->data[arrsz] == -99., PETSC_COMM_SELF, PETSC_ERR_PLIB, "pc_gamg->data[arrsz %" PetscInt_FMT "] %g != -99.", arrsz, (double)pc_gamg->data[arrsz]);
 74:   pc_gamg->data_sz = arrsz;
 75:   PetscFunctionReturn(PETSC_SUCCESS);
 76: }

 78: // PetscClangLinter pragma disable: -fdoc-sowing-chars
 79: /*
 80:    PCSetData_GEO

 82:   Input Parameter:
 83:    . pc -
 84: */
 85: static PetscErrorCode PCSetData_GEO(PC pc, Mat m)
 86: {
 87:   PetscFunctionBegin;
 88:   SETERRQ(PetscObjectComm((PetscObject)pc), PETSC_ERR_PLIB, "GEO MG needs coordinates");
 89: }

 91: static PetscErrorCode PCSetFromOptions_GEO(PC pc, PetscOptionItems PetscOptionsObject)
 92: {
 93:   PetscFunctionBegin;
 94:   PetscOptionsHeadBegin(PetscOptionsObject, "GAMG-GEO options");
 95:   {
 96:     /* -pc_gamg_sa_nsmooths */
 97:     /* pc_gamg_sa->smooths = 0; */
 98:     /* ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths", */
 99:     /*                        "smoothing steps for smoothed aggregation, usually 1 (0)", */
100:     /*                        "PCGAMGSetNSmooths_AGG", */
101:     /*                        pc_gamg_sa->smooths, */
102:     /*                        &pc_gamg_sa->smooths, */
103:     /*                        &flag);  */
104:   }
105:   PetscOptionsHeadEnd();
106:   PetscFunctionReturn(PETSC_SUCCESS);
107: }

109: // PetscClangLinter pragma disable: -fdoc-sowing-chars
110: /*
111:  triangulateAndFormProl

113:    Input Parameter:
114:    . selected_2 - list of selected local ID, includes selected ghosts
115:    . data_stride -
116:    . coords[2*data_stride] - column vector of local coordinates w/ ghosts
117:    . nselected_1 - selected IDs that go with base (1) graph includes selected ghosts
118:    . clid_lid_1[nselected_1] - lids of selected (c) nodes   ???????????
119:    . agg_lists_1 - list of aggregates selected_1 vertices of aggregate unselected vertices
120:    . crsGID[selected.size()] - global index for prolongation operator
121:    . bs - block size
122:   Output Parameter:
123:    . a_Prol - prolongation operator
124:    . a_worst_best - measure of worst missed fine vertex, 0 is no misses
125: */
126: static PetscErrorCode triangulateAndFormProl(IS selected_2, PetscInt data_stride, PetscReal coords[], PetscInt nselected_1, const PetscInt clid_lid_1[], const PetscCoarsenData *agg_lists_1, const PetscInt crsGID[], PetscInt bs, Mat a_Prol, PetscReal *a_worst_best)
127: {
128: #if defined(PETSC_HAVE_TRIANGLE)
129:   PetscInt             jj, tid, tt, idx, nselected_2;
130:   struct triangulateio in, mid;
131:   const PetscInt      *selected_idx_2;
132:   PetscMPIInt          rank;
133:   PetscInt             Istart, Iend, nFineLoc, myFine0;
134:   int                  kk, nPlotPts, sid;
135:   MPI_Comm             comm;
136:   PetscReal            tm;

138:   PetscFunctionBegin;
139:   PetscCall(PetscObjectGetComm((PetscObject)a_Prol, &comm));
140:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
141:   PetscCall(ISGetSize(selected_2, &nselected_2));
142:   if (nselected_2 == 1 || nselected_2 == 2) { /* 0 happens on idle processors */
143:     *a_worst_best = 100.0;                    /* this will cause a stop, but not globalized (should not happen) */
144:   } else *a_worst_best = 0.0;
145:   PetscCallMPI(MPIU_Allreduce(a_worst_best, &tm, 1, MPIU_REAL, MPIU_MAX, comm));
146:   if (tm > 0.0) {
147:     *a_worst_best = 100.0;
148:     PetscFunctionReturn(PETSC_SUCCESS);
149:   }
150:   PetscCall(MatGetOwnershipRange(a_Prol, &Istart, &Iend));
151:   nFineLoc = (Iend - Istart) / bs;
152:   myFine0  = Istart / bs;
153:   PetscCall(PetscCIntCast(nFineLoc, &nPlotPts)); /* locals */
154:   /* triangle */
155:   /* Define input points - in */
156:   PetscCall(PetscCIntCast(nselected_2, &in.numberofpoints));
157:   in.numberofpointattributes = 0;
158:   /* get nselected points */
159:   PetscCall(PetscMalloc1(2 * nselected_2, &in.pointlist));
160:   PetscCall(ISGetIndices(selected_2, &selected_idx_2));

162:   for (kk = 0, sid = 0; kk < nselected_2; kk++, sid += 2) {
163:     PetscInt lid          = selected_idx_2[kk];
164:     in.pointlist[sid]     = coords[lid];
165:     in.pointlist[sid + 1] = coords[data_stride + lid];
166:     if (lid >= nFineLoc) nPlotPts++;
167:   }
168:   PetscCheck(sid == 2 * nselected_2, PETSC_COMM_SELF, PETSC_ERR_PLIB, "sid %d != 2*nselected_2 %" PetscInt_FMT, sid, nselected_2);

170:   in.numberofsegments      = 0;
171:   in.numberofedges         = 0;
172:   in.numberofholes         = 0;
173:   in.numberofregions       = 0;
174:   in.trianglelist          = NULL;
175:   in.segmentmarkerlist     = NULL;
176:   in.pointattributelist    = NULL;
177:   in.pointmarkerlist       = NULL;
178:   in.triangleattributelist = NULL;
179:   in.trianglearealist      = NULL;
180:   in.segmentlist           = NULL;
181:   in.holelist              = NULL;
182:   in.regionlist            = NULL;
183:   in.edgelist              = NULL;
184:   in.edgemarkerlist        = NULL;
185:   in.normlist              = NULL;

187:   /* triangulate */
188:   mid.pointlist = NULL; /* Not needed if -N switch used. */
189:   /* Not needed if -N switch used or number of point attributes is zero: */
190:   mid.pointattributelist = NULL;
191:   mid.pointmarkerlist    = NULL; /* Not needed if -N or -B switch used. */
192:   mid.trianglelist       = NULL; /* Not needed if -E switch used. */
193:   /* Not needed if -E switch used or number of triangle attributes is zero: */
194:   mid.triangleattributelist = NULL;
195:   mid.neighborlist          = NULL; /* Needed only if -n switch used. */
196:   /* Needed only if segments are output (-p or -c) and -P not used: */
197:   mid.segmentlist = NULL;
198:   /* Needed only if segments are output (-p or -c) and -P and -B not used: */
199:   mid.segmentmarkerlist = NULL;
200:   mid.edgelist          = NULL; /* Needed only if -e switch used. */
201:   mid.edgemarkerlist    = NULL; /* Needed if -e used and -B not used. */
202:   mid.numberoftriangles = 0;

204:   /* Triangulate the points.  Switches are chosen to read and write a  */
205:   /*   PSLG (p), preserve the convex hull (c), number everything from  */
206:   /*   zero (z), assign a regional attribute to each element (A), and  */
207:   /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
208:   /*   neighbor list (n).                                            */
209:   if (nselected_2 != 0) {  /* inactive processor */
210:     char args[] = "npczQ"; /* c is needed ? */
211:     triangulate(args, &in, &mid, (struct triangulateio *)NULL);
212:     /* output .poly files for 'showme' */
213:     if (!PETSC_TRUE) {
214:       static int level = 1;
215:       FILE      *file;
216:       char       fname[32];

218:       PetscCall(PetscSNPrintf(fname, PETSC_STATIC_ARRAY_LENGTH(fname), "C%d_%d.poly", level, rank));
219:       file = fopen(fname, "w");
220:       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
221:       fprintf(file, "%d  %d  %d  %d\n", in.numberofpoints, 2, 0, 0);
222:       /* Following lines: <vertex #> <x> <y> */
223:       for (kk = 0, sid = 0; kk < in.numberofpoints; kk++, sid += 2) fprintf(file, "%d %e %e\n", kk, in.pointlist[sid], in.pointlist[sid + 1]);
224:       /* One line: <# of segments> <# of boundary markers (0 or 1)> */
225:       fprintf(file, "%d  %d\n", 0, 0);
226:       /* Following lines: <segment #> <endpoint> <endpoint> [boundary marker] */
227:       /* One line: <# of holes> */
228:       fprintf(file, "%d\n", 0);
229:       /* Following lines: <hole #> <x> <y> */
230:       /* Optional line: <# of regional attributes and/or area constraints> */
231:       /* Optional following lines: <region #> <x> <y> <attribute> <maximum area> */
232:       fclose(file);

234:       /* elems */
235:       PetscCall(PetscSNPrintf(fname, PETSC_STATIC_ARRAY_LENGTH(fname), "C%d_%d.ele", level, rank));
236:       file = fopen(fname, "w");
237:       /* First line: <# of triangles> <nodes per triangle> <# of attributes> */
238:       fprintf(file, "%d %d %d\n", mid.numberoftriangles, 3, 0);
239:       /* Remaining lines: <triangle #> <node> <node> <node> ... [attributes] */
240:       for (kk = 0, sid = 0; kk < mid.numberoftriangles; kk++, sid += 3) fprintf(file, "%d %d %d %d\n", kk, mid.trianglelist[sid], mid.trianglelist[sid + 1], mid.trianglelist[sid + 2]);
241:       fclose(file);

243:       PetscCall(PetscSNPrintf(fname, PETSC_STATIC_ARRAY_LENGTH(fname), "C%d_%d.node", level, rank));
244:       file = fopen(fname, "w");
245:       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
246:       /* fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0); */
247:       fprintf(file, "%d  %d  %d  %d\n", nPlotPts, 2, 0, 0);
248:       /* Following lines: <vertex #> <x> <y> */
249:       for (kk = 0, sid = 0; kk < in.numberofpoints; kk++, sid += 2) fprintf(file, "%d %e %e\n", kk, in.pointlist[sid], in.pointlist[sid + 1]);

251:       sid /= 2;
252:       for (jj = 0; jj < nFineLoc; jj++) {
253:         PetscBool sel = PETSC_TRUE;
254:         for (kk = 0; kk < nselected_2 && sel; kk++) {
255:           PetscInt lid = selected_idx_2[kk];
256:           if (lid == jj) sel = PETSC_FALSE;
257:         }
258:         if (sel) fprintf(file, "%d %e %e\n", sid++, (double)coords[jj], (double)coords[data_stride + jj]);
259:       }
260:       fclose(file);
261:       PetscCheck(sid == nPlotPts, PETSC_COMM_SELF, PETSC_ERR_PLIB, "sid %d != nPlotPts %d", sid, nPlotPts);
262:       level++;
263:     }
264:   }
265:   { /* form P - setup some maps */
266:     PetscInt clid, mm, *nTri, *node_tri;

268:     PetscCall(PetscMalloc2(nselected_2, &node_tri, nselected_2, &nTri));

270:     /* need list of triangles on node */
271:     for (kk = 0; kk < nselected_2; kk++) nTri[kk] = 0;
272:     for (tid = 0, kk = 0; tid < mid.numberoftriangles; tid++) {
273:       for (jj = 0; jj < 3; jj++) {
274:         PetscInt cid = mid.trianglelist[kk++];
275:         if (nTri[cid] == 0) node_tri[cid] = tid;
276:         nTri[cid]++;
277:       }
278:     }
279:   #define EPS 1.e-12
280:     /* find points and set prolongation */
281:     for (mm = clid = 0; mm < nFineLoc; mm++) {
282:       PetscBool ise;
283:       PetscCall(PetscCDIsEmptyAt(agg_lists_1, mm, &ise));
284:       if (!ise) {
285:         const PetscInt lid = mm;
286:         PetscScalar    AA[3][3];
287:         PetscBLASInt   N = 3, NRHS = 1, LDA = 3, IPIV[3], LDB = 3;
288:         PetscCDIntNd  *pos;

290:         PetscCall(PetscCDGetHeadPos(agg_lists_1, lid, &pos));
291:         while (pos) {
292:           PetscInt flid;
293:           PetscCall(PetscCDIntNdGetID(pos, &flid));
294:           PetscCall(PetscCDGetNextPos(agg_lists_1, lid, &pos));

296:           if (flid < nFineLoc) { /* could be a ghost */
297:             PetscInt       bestTID    = -1;
298:             PetscReal      best_alpha = 1.e10;
299:             const PetscInt fgid       = flid + myFine0;
300:             /* compute shape function for gid */
301:             const PetscReal fcoord[3] = {coords[flid], coords[data_stride + flid], 1.0};
302:             PetscBool       haveit    = PETSC_FALSE;
303:             PetscScalar     alpha[3];
304:             PetscInt        clids[3];

306:             /* look for it */
307:             for (tid = node_tri[clid], jj = 0; jj < 5 && !haveit && tid != -1; jj++) {
308:               for (tt = 0; tt < 3; tt++) {
309:                 PetscInt cid2 = mid.trianglelist[3 * tid + tt];
310:                 PetscInt lid2 = selected_idx_2[cid2];
311:                 AA[tt][0]     = coords[lid2];
312:                 AA[tt][1]     = coords[data_stride + lid2];
313:                 AA[tt][2]     = 1.0;
314:                 clids[tt]     = cid2; /* store for interp */
315:               }

317:               for (tt = 0; tt < 3; tt++) alpha[tt] = (PetscScalar)fcoord[tt];

319:               PetscCallLAPACKInfo("LAPACKgesv", LAPACKgesv_(&N, &NRHS, (PetscScalar *)AA, &LDA, IPIV, alpha, &LDB, &info));
320:               {
321:                 PetscBool have   = PETSC_TRUE;
322:                 PetscReal lowest = 1.e10;
323:                 for (tt = 0, idx = 0; tt < 3; tt++) {
324:                   if (PetscRealPart(alpha[tt]) > (1.0 + EPS) || PetscRealPart(alpha[tt]) < -EPS) have = PETSC_FALSE;
325:                   if (PetscRealPart(alpha[tt]) < lowest) {
326:                     lowest = PetscRealPart(alpha[tt]);
327:                     idx    = tt;
328:                   }
329:                 }
330:                 haveit = have;
331:               }
332:               tid = mid.neighborlist[3 * tid + idx];
333:             }

335:             if (!haveit) {
336:               /* brute force */
337:               for (tid = 0; tid < mid.numberoftriangles && !haveit; tid++) {
338:                 for (tt = 0; tt < 3; tt++) {
339:                   PetscInt cid2 = mid.trianglelist[3 * tid + tt];
340:                   PetscInt lid2 = selected_idx_2[cid2];
341:                   AA[tt][0]     = coords[lid2];
342:                   AA[tt][1]     = coords[data_stride + lid2];
343:                   AA[tt][2]     = 1.0;
344:                   clids[tt]     = cid2; /* store for interp */
345:                 }
346:                 for (tt = 0; tt < 3; tt++) alpha[tt] = fcoord[tt];
347:                 PetscCallLAPACKInfo("LAPACKgesv", LAPACKgesv_(&N, &NRHS, (PetscScalar *)AA, &LDA, IPIV, alpha, &LDB, &info));
348:                 {
349:                   PetscBool have  = PETSC_TRUE;
350:                   PetscReal worst = 0.0, v;
351:                   for (tt = 0; tt < 3 && have; tt++) {
352:                     if (PetscRealPart(alpha[tt]) > 1.0 + EPS || PetscRealPart(alpha[tt]) < -EPS) have = PETSC_FALSE;
353:                     if ((v = PetscAbs(PetscRealPart(alpha[tt]) - 0.5)) > worst) worst = v;
354:                   }
355:                   if (worst < best_alpha) {
356:                     best_alpha = worst;
357:                     bestTID    = tid;
358:                   }
359:                   haveit = have;
360:                 }
361:               }
362:             }
363:             if (!haveit) {
364:               if (best_alpha > *a_worst_best) *a_worst_best = best_alpha;
365:               /* use best one */
366:               for (tt = 0; tt < 3; tt++) {
367:                 PetscInt cid2 = mid.trianglelist[3 * bestTID + tt];
368:                 PetscInt lid2 = selected_idx_2[cid2];
369:                 AA[tt][0]     = coords[lid2];
370:                 AA[tt][1]     = coords[data_stride + lid2];
371:                 AA[tt][2]     = 1.0;
372:                 clids[tt]     = cid2; /* store for interp */
373:               }
374:               for (tt = 0; tt < 3; tt++) alpha[tt] = fcoord[tt];
375:               PetscCallLAPACKInfo("LAPACKgesv", LAPACKgesv_(&N, &NRHS, (PetscScalar *)AA, &LDA, IPIV, alpha, &LDB, &info));
376:             }

378:             /* put in row of P */
379:             for (idx = 0; idx < 3; idx++) {
380:               PetscScalar shp = alpha[idx];
381:               if (PetscAbs(PetscRealPart(shp)) > 1.e-6) {
382:                 PetscInt cgid = crsGID[clids[idx]];
383:                 PetscInt jj = cgid * bs, ii = fgid * bs; /* need to gloalize */
384:                 for (tt = 0; tt < bs; tt++, ii++, jj++) PetscCall(MatSetValues(a_Prol, 1, &ii, 1, &jj, &shp, INSERT_VALUES));
385:               }
386:             }
387:           }
388:         } /* aggregates iterations */
389:         clid++;
390:       } /* a coarse agg */
391:     } /* for all fine nodes */

393:     PetscCall(ISRestoreIndices(selected_2, &selected_idx_2));
394:     PetscCall(MatAssemblyBegin(a_Prol, MAT_FINAL_ASSEMBLY));
395:     PetscCall(MatAssemblyEnd(a_Prol, MAT_FINAL_ASSEMBLY));

397:     PetscCall(PetscFree2(node_tri, nTri));
398:   }
399:   free(mid.trianglelist);
400:   free(mid.neighborlist);
401:   free(mid.segmentlist);
402:   free(mid.segmentmarkerlist);
403:   free(mid.pointlist);
404:   free(mid.pointmarkerlist);
405:   PetscCall(PetscFree(in.pointlist));
406:   PetscFunctionReturn(PETSC_SUCCESS);
407: #else
408:   SETERRQ(PetscObjectComm((PetscObject)a_Prol), PETSC_ERR_PLIB, "configure with TRIANGLE to use geometric MG");
409: #endif
410: }

412: // PetscClangLinter pragma disable: -fdoc-sowing-chars
413: /*
414:    getGIDsOnSquareGraph - square graph, get

416:    Input Parameter:
417:    . nselected_1 - selected local indices (includes ghosts in input Gmat1)
418:    . clid_lid_1 - [nselected_1] lids of selected nodes
419:    . Gmat1 - graph that goes with 'selected_1'
420:    Output Parameter:
421:    . a_selected_2 - selected local indices (includes ghosts in output a_Gmat_2)
422:    . a_Gmat_2 - graph that is squared of 'Gmat_1'
423:    . a_crsGID[a_selected_2.size()] - map of global IDs of coarse grid nodes
424: */
425: static PetscErrorCode getGIDsOnSquareGraph(PC pc, PetscInt nselected_1, const PetscInt clid_lid_1[], const Mat Gmat1, IS *a_selected_2, Mat *a_Gmat_2, PetscInt **a_crsGID)
426: {
427:   PetscMPIInt size;
428:   PetscInt   *crsGID, kk, my0, Iend, nloc;
429:   MPI_Comm    comm;

431:   PetscFunctionBegin;
432:   PetscCall(PetscObjectGetComm((PetscObject)Gmat1, &comm));
433:   PetscCallMPI(MPI_Comm_size(comm, &size));
434:   PetscCall(MatGetOwnershipRange(Gmat1, &my0, &Iend)); /* AIJ */
435:   nloc = Iend - my0;                                   /* this does not change */

437:   if (size == 1) { /* not much to do in serial */
438:     PetscCall(PetscMalloc1(nselected_1, &crsGID));
439:     for (kk = 0; kk < nselected_1; kk++) crsGID[kk] = kk;
440:     *a_Gmat_2 = NULL;
441:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nselected_1, clid_lid_1, PETSC_COPY_VALUES, a_selected_2));
442:   } else {
443:     PetscInt     idx, num_fine_ghosts, num_crs_ghost, myCrs0;
444:     Mat_MPIAIJ  *mpimat2;
445:     Mat          Gmat2;
446:     Vec          locState;
447:     PetscScalar *cpcol_state;

449:     /* scan my coarse zero gid, set 'lid_state' with coarse GID */
450:     kk = nselected_1;
451:     PetscCallMPI(MPI_Scan(&kk, &myCrs0, 1, MPIU_INT, MPI_SUM, comm));
452:     myCrs0 -= nselected_1;

454:     if (a_Gmat_2) { /* output */
455:       /* grow graph to get wider set of selected vertices to cover fine grid, invalidates 'llist' */
456:       PetscCall(PCGAMGSquareGraph_GAMG(pc, Gmat1, &Gmat2));
457:       *a_Gmat_2 = Gmat2;  /* output */
458:     } else Gmat2 = Gmat1; /* use local to get crsGIDs at least */
459:     /* get coarse grid GIDS for selected (locals and ghosts) */
460:     mpimat2 = (Mat_MPIAIJ *)Gmat2->data;
461:     PetscCall(MatCreateVecs(Gmat2, &locState, NULL));
462:     PetscCall(VecSet(locState, -1)); /* set with UNKNOWN state */
463:     for (kk = 0; kk < nselected_1; kk++) {
464:       PetscInt    fgid = clid_lid_1[kk] + my0;
465:       PetscScalar v    = (PetscScalar)(kk + myCrs0);
466:       PetscCall(VecSetValues(locState, 1, &fgid, &v, INSERT_VALUES)); /* set with PID */
467:     }
468:     PetscCall(VecAssemblyBegin(locState));
469:     PetscCall(VecAssemblyEnd(locState));
470:     PetscCall(VecScatterBegin(mpimat2->Mvctx, locState, mpimat2->lvec, INSERT_VALUES, SCATTER_FORWARD));
471:     PetscCall(VecScatterEnd(mpimat2->Mvctx, locState, mpimat2->lvec, INSERT_VALUES, SCATTER_FORWARD));
472:     PetscCall(VecGetLocalSize(mpimat2->lvec, &num_fine_ghosts));
473:     PetscCall(VecGetArray(mpimat2->lvec, &cpcol_state));
474:     for (kk = 0, num_crs_ghost = 0; kk < num_fine_ghosts; kk++) {
475:       if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) num_crs_ghost++;
476:     }
477:     PetscCall(PetscMalloc1(nselected_1 + num_crs_ghost, &crsGID)); /* output */
478:     {
479:       PetscInt *selected_set;
480:       PetscCall(PetscMalloc1(nselected_1 + num_crs_ghost, &selected_set));
481:       /* do ghost of 'crsGID' */
482:       for (kk = 0, idx = nselected_1; kk < num_fine_ghosts; kk++) {
483:         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
484:           PetscInt cgid     = (PetscInt)PetscRealPart(cpcol_state[kk]);
485:           selected_set[idx] = nloc + kk;
486:           crsGID[idx++]     = cgid;
487:         }
488:       }
489:       PetscCheck(idx == (nselected_1 + num_crs_ghost), PETSC_COMM_SELF, PETSC_ERR_PLIB, "idx %" PetscInt_FMT " != (nselected_1 %" PetscInt_FMT " + num_crs_ghost %" PetscInt_FMT ")", idx, nselected_1, num_crs_ghost);
490:       PetscCall(VecRestoreArray(mpimat2->lvec, &cpcol_state));
491:       /* do locals in 'crsGID' */
492:       PetscCall(VecGetArray(locState, &cpcol_state));
493:       for (kk = 0, idx = 0; kk < nloc; kk++) {
494:         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
495:           PetscInt cgid     = (PetscInt)PetscRealPart(cpcol_state[kk]);
496:           selected_set[idx] = kk;
497:           crsGID[idx++]     = cgid;
498:         }
499:       }
500:       PetscCheck(idx == nselected_1, PETSC_COMM_SELF, PETSC_ERR_PLIB, "idx %" PetscInt_FMT " != nselected_1 %" PetscInt_FMT, idx, nselected_1);
501:       PetscCall(VecRestoreArray(locState, &cpcol_state));

503:       if (a_selected_2 != NULL) { /* output */
504:         PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nselected_1 + num_crs_ghost, selected_set, PETSC_OWN_POINTER, a_selected_2));
505:       } else {
506:         PetscCall(PetscFree(selected_set));
507:       }
508:     }
509:     PetscCall(VecDestroy(&locState));
510:   }
511:   *a_crsGID = crsGID; /* output */
512:   PetscFunctionReturn(PETSC_SUCCESS);
513: }

515: static PetscErrorCode PCGAMGCreateGraph_GEO(PC pc, Mat Amat, Mat *a_Gmat)
516: {
517:   PC_MG          *mg      = (PC_MG *)pc->data;
518:   PC_GAMG        *pc_gamg = (PC_GAMG *)mg->innerctx;
519:   const PetscReal vfilter = pc_gamg->threshold[0];

521:   PetscFunctionBegin;
522:   PetscCall(MatCreateGraph(Amat, PETSC_TRUE, PETSC_TRUE, vfilter, 0, NULL, a_Gmat));
523:   PetscFunctionReturn(PETSC_SUCCESS);
524: }

526: static PetscErrorCode PCGAMGCoarsen_GEO(PC a_pc, Mat *a_Gmat, PetscCoarsenData **a_llist_parent)
527: {
528:   PetscInt   Istart, Iend, nloc, kk, Ii, ncols;
529:   IS         perm;
530:   GAMGNode  *gnodes;
531:   PetscInt  *permute;
532:   Mat        Gmat = *a_Gmat;
533:   MPI_Comm   comm;
534:   MatCoarsen crs;

536:   PetscFunctionBegin;
537:   PetscCall(PetscObjectGetComm((PetscObject)a_pc, &comm));

539:   PetscCall(MatGetOwnershipRange(Gmat, &Istart, &Iend));
540:   nloc = (Iend - Istart);

542:   /* create random permutation with sort for geo-mg */
543:   PetscCall(PetscMalloc1(nloc, &gnodes));
544:   PetscCall(PetscMalloc1(nloc, &permute));

546:   for (Ii = Istart; Ii < Iend; Ii++) { /* locals only? */
547:     PetscCall(MatGetRow(Gmat, Ii, &ncols, NULL, NULL));
548:     {
549:       PetscInt lid       = Ii - Istart;
550:       gnodes[lid].lid    = lid;
551:       gnodes[lid].degree = ncols;
552:     }
553:     PetscCall(MatRestoreRow(Gmat, Ii, &ncols, NULL, NULL));
554:   }
555:   if (PETSC_TRUE) {
556:     PetscRandom rand;
557:     PetscBool  *bIndexSet;
558:     PetscReal   rr;
559:     PetscInt    iSwapIndex;

561:     PetscCall(PetscRandomCreate(comm, &rand));
562:     PetscCall(PetscCalloc1(nloc, &bIndexSet));
563:     for (Ii = 0; Ii < nloc; Ii++) {
564:       PetscCall(PetscRandomGetValueReal(rand, &rr));
565:       iSwapIndex = (PetscInt)(rr * nloc);
566:       if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
567:         GAMGNode iTemp        = gnodes[iSwapIndex];
568:         gnodes[iSwapIndex]    = gnodes[Ii];
569:         gnodes[Ii]            = iTemp;
570:         bIndexSet[Ii]         = PETSC_TRUE;
571:         bIndexSet[iSwapIndex] = PETSC_TRUE;
572:       }
573:     }
574:     PetscCall(PetscRandomDestroy(&rand));
575:     PetscCall(PetscFree(bIndexSet));
576:   }
577:   /* only sort locals */
578:   if (gnodes) qsort(gnodes, nloc, sizeof(GAMGNode), petsc_geo_mg_compare);
579:   /* create IS of permutation */
580:   for (kk = 0; kk < nloc; kk++) permute[kk] = gnodes[kk].lid; /* locals only */
581:   PetscCall(PetscFree(gnodes));
582:   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_OWN_POINTER, &perm));

584:   /* get MIS aggs */

586:   PetscCall(MatCoarsenCreate(comm, &crs));
587:   PetscCall(MatCoarsenSetType(crs, MATCOARSENMIS));
588:   PetscCall(MatCoarsenSetGreedyOrdering(crs, perm));
589:   PetscCall(MatCoarsenSetAdjacency(crs, Gmat));
590:   PetscCall(MatCoarsenSetStrictAggs(crs, PETSC_FALSE));
591:   PetscCall(MatCoarsenApply(crs));
592:   PetscCall(MatCoarsenGetData(crs, a_llist_parent));
593:   PetscCall(MatCoarsenDestroy(&crs));

595:   PetscCall(ISDestroy(&perm));
596:   PetscFunctionReturn(PETSC_SUCCESS);
597: }

599: static PetscErrorCode PCGAMGProlongator_GEO(PC pc, Mat Amat, PetscCoarsenData *agg_lists, Mat *a_P_out)
600: {
601:   PC_MG          *mg      = (PC_MG *)pc->data;
602:   PC_GAMG        *pc_gamg = (PC_GAMG *)mg->innerctx;
603:   const PetscInt  dim = pc_gamg->data_cell_cols, data_cols = pc_gamg->data_cell_cols;
604:   PetscInt        Istart, Iend, nloc, my0, jj, kk, ncols, nLocalSelected, bs, *clid_flid;
605:   Mat             Prol, Gmat;
606:   PetscMPIInt     rank, size;
607:   MPI_Comm        comm;
608:   IS              selected_2, selected_1;
609:   const PetscInt *selected_idx;
610:   MatType         mtype;

612:   PetscFunctionBegin;
613:   PetscCall(PetscObjectGetComm((PetscObject)Amat, &comm));

615:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
616:   PetscCallMPI(MPI_Comm_size(comm, &size));
617:   PetscCall(MatGetOwnershipRange(Amat, &Istart, &Iend));
618:   PetscCall(MatGetBlockSize(Amat, &bs));
619:   nloc = (Iend - Istart) / bs;
620:   my0  = Istart / bs;
621:   PetscCheck((Iend - Istart) % bs == 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "(Iend %" PetscInt_FMT " - Istart %" PetscInt_FMT ") %% bs %" PetscInt_FMT, Iend, Istart, bs);

623:   /* get 'nLocalSelected' */
624:   PetscCall(PetscCDGetMat(agg_lists, &Gmat)); // get auxiliary matrix for ghost edges
625:   PetscCall(PetscCDGetNonemptyIS(agg_lists, &selected_1));
626:   PetscCall(ISGetSize(selected_1, &jj));
627:   PetscCall(PetscMalloc1(jj, &clid_flid));
628:   PetscCall(ISGetIndices(selected_1, &selected_idx));
629:   for (kk = 0, nLocalSelected = 0; kk < jj; kk++) {
630:     PetscInt lid = selected_idx[kk];
631:     if (lid < nloc) {
632:       PetscCall(MatGetRow(Gmat, lid + my0, &ncols, NULL, NULL));
633:       if (ncols > 1) clid_flid[nLocalSelected++] = lid; /* filter out singletons */
634:       PetscCall(MatRestoreRow(Gmat, lid + my0, &ncols, NULL, NULL));
635:     }
636:   }
637:   PetscCall(ISRestoreIndices(selected_1, &selected_idx));
638:   PetscCall(ISDestroy(&selected_1)); /* this is selected_1 in serial */

640:   /* create prolongator  matrix */
641:   PetscCall(MatGetType(Amat, &mtype));
642:   PetscCall(MatCreate(comm, &Prol));
643:   PetscCall(MatSetSizes(Prol, nloc * bs, nLocalSelected * bs, PETSC_DETERMINE, PETSC_DETERMINE));
644:   PetscCall(MatSetBlockSizes(Prol, bs, bs));
645:   PetscCall(MatSetType(Prol, mtype));
646:   PetscCall(MatSeqAIJSetPreallocation(Prol, 3 * data_cols, NULL));
647:   PetscCall(MatMPIAIJSetPreallocation(Prol, 3 * data_cols, NULL, 3 * data_cols, NULL));

649:   /* can get all points "removed" - but not on geomg */
650:   PetscCall(MatGetSize(Prol, &kk, &jj));
651:   if (!jj) {
652:     PetscCall(PetscInfo(pc, "ERROE: no selected points on coarse grid\n"));
653:     PetscCall(PetscFree(clid_flid));
654:     PetscCall(MatDestroy(&Prol));
655:     *a_P_out = NULL; /* out */
656:     PetscFunctionReturn(PETSC_SUCCESS);
657:   }

659:   {
660:     PetscReal *coords;
661:     PetscInt   data_stride;
662:     PetscInt  *crsGID = NULL;
663:     Mat        Gmat2;

665:     PetscCheck(dim == data_cols, PETSC_COMM_SELF, PETSC_ERR_PLIB, "dim %" PetscInt_FMT " != data_cols %" PetscInt_FMT, dim, data_cols);
666:     /* grow ghost data for better coarse grid cover of fine grid */
667:     /* messy method, squares graph and gets some data */
668:     PetscCall(getGIDsOnSquareGraph(pc, nLocalSelected, clid_flid, Gmat, &selected_2, &Gmat2, &crsGID));
669:     /* llist is now not valid wrt squared graph, but will work as iterator in 'triangulateAndFormProl' */
670:     /* create global vector of coorindates in 'coords' */
671:     if (size > 1) {
672:       PetscCall(PCGAMGGetDataWithGhosts(Gmat2, dim, pc_gamg->data, &data_stride, &coords));
673:     } else {
674:       coords      = pc_gamg->data;
675:       data_stride = pc_gamg->data_sz / pc_gamg->data_cell_cols;
676:     }
677:     PetscCall(MatDestroy(&Gmat2));
678:     /* triangulate */
679:     {
680:       PetscReal metric, tm;

682:       PetscCheck(dim == 2, comm, PETSC_ERR_PLIB, "3D not implemented for 'geo' AMG");
683:       PetscCall(triangulateAndFormProl(selected_2, data_stride, coords, nLocalSelected, clid_flid, agg_lists, crsGID, bs, Prol, &metric));
684:       PetscCall(PetscFree(crsGID));

686:       /* clean up and create coordinates for coarse grid (output) */
687:       if (size > 1) PetscCall(PetscFree(coords));

689:       PetscCallMPI(MPIU_Allreduce(&metric, &tm, 1, MPIU_REAL, MPIU_MAX, comm));
690:       if (tm > 1.) { /* needs to be globalized - should not happen */
691:         PetscCall(PetscInfo(pc, " failed metric for coarse grid %e\n", (double)tm));
692:         PetscCall(MatDestroy(&Prol));
693:       } else if (metric > .0) {
694:         PetscCall(PetscInfo(pc, "worst metric for coarse grid = %e\n", (double)metric));
695:       }
696:     }
697:     { /* create next coords - output */
698:       PetscReal *crs_crds;
699:       PetscCall(PetscMalloc1(dim * nLocalSelected, &crs_crds));
700:       for (kk = 0; kk < nLocalSelected; kk++) { /* grab local select nodes to promote - output */
701:         PetscInt lid = clid_flid[kk];
702:         for (jj = 0; jj < dim; jj++) crs_crds[jj * nLocalSelected + kk] = pc_gamg->data[jj * nloc + lid];
703:       }

705:       PetscCall(PetscFree(pc_gamg->data));
706:       pc_gamg->data    = crs_crds; /* out */
707:       pc_gamg->data_sz = dim * nLocalSelected;
708:     }
709:     PetscCall(ISDestroy(&selected_2));
710:   }

712:   *a_P_out = Prol; /* out */
713:   PetscCall(PetscFree(clid_flid));
714:   PetscFunctionReturn(PETSC_SUCCESS);
715: }

717: static PetscErrorCode PCDestroy_GAMG_GEO(PC pc)
718: {
719:   PetscFunctionBegin;
720:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", NULL));
721:   PetscFunctionReturn(PETSC_SUCCESS);
722: }

724: PetscErrorCode PCCreateGAMG_GEO(PC pc)
725: {
726:   PC_MG   *mg      = (PC_MG *)pc->data;
727:   PC_GAMG *pc_gamg = (PC_GAMG *)mg->innerctx;

729:   PetscFunctionBegin;
730:   pc_gamg->ops->setfromoptions = PCSetFromOptions_GEO;
731:   pc_gamg->ops->destroy        = PCDestroy_GAMG_GEO;
732:   /* reset does not do anything; setup not virtual */

734:   /* set internal function pointers */
735:   pc_gamg->ops->creategraph       = PCGAMGCreateGraph_GEO;
736:   pc_gamg->ops->coarsen           = PCGAMGCoarsen_GEO;
737:   pc_gamg->ops->prolongator       = PCGAMGProlongator_GEO;
738:   pc_gamg->ops->optprolongator    = NULL;
739:   pc_gamg->ops->createdefaultdata = PCSetData_GEO;

741:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCSetCoordinates_C", PCSetCoordinates_GEO));
742:   PetscFunctionReturn(PETSC_SUCCESS);
743: }