xref: /petsc/src/ksp/pc/impls/gamg/geo.c (revision 5e71baeff2f3138f93cd4f5927dfd596eb8325cc)
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 
7 #if defined(PETSC_HAVE_TRIANGLE)
8 #define REAL PetscReal
9 #include <triangle.h>
10 #endif
11 
12 #include <petscblaslapack.h>
13 
14 /* Private context for the GAMG preconditioner */
15 typedef struct {
16   PetscInt lid;            /* local vertex index */
17   PetscInt degree;         /* vertex degree */
18 } GAMGNode;
19 
20 int petsc_geo_mg_compare(const void *a, const void *b)
21 {
22   return (((GAMGNode*)a)->degree - ((GAMGNode*)b)->degree);
23 }
24 
25 /* -------------------------------------------------------------------------- */
26 /*
27    PCSetCoordinates_GEO
28 
29    Input Parameter:
30    .  pc - the preconditioner context
31 */
32 PetscErrorCode PCSetCoordinates_GEO(PC pc, PetscInt ndm, PetscInt a_nloc, PetscReal *coords)
33 {
34   PC_MG          *mg      = (PC_MG*)pc->data;
35   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
36   PetscErrorCode ierr;
37   PetscInt       arrsz,bs,my0,kk,ii,nloc,Iend;
38   Mat            Amat = pc->pmat;
39 
40   PetscFunctionBegin;
41   PetscValidHeaderSpecific(Amat, MAT_CLASSID, 1);
42   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
43 
44   ierr = MatGetOwnershipRange(Amat, &my0, &Iend);CHKERRQ(ierr);
45   nloc = (Iend-my0)/bs;
46 
47   if (nloc!=a_nloc) SETERRQ2(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Stokes not supported nloc = %d %d.",a_nloc,nloc);
48   if ((Iend-my0)%bs!=0) SETERRQ1(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Bad local size %d.",nloc);
49 
50   pc_gamg->data_cell_rows = 1;
51   if (!coords && nloc > 0) SETERRQ(PetscObjectComm((PetscObject)Amat),PETSC_ERR_ARG_WRONG, "Need coordinates for pc_gamg_type 'geo'.");
52   pc_gamg->data_cell_cols = ndm; /* coordinates */
53 
54   arrsz = nloc*pc_gamg->data_cell_rows*pc_gamg->data_cell_cols;
55 
56   /* create data - syntactic sugar that should be refactored at some point */
57   if (!pc_gamg->data || (pc_gamg->data_sz != arrsz)) {
58     ierr = PetscFree(pc_gamg->data);CHKERRQ(ierr);
59     ierr = PetscMalloc1(arrsz+1, &pc_gamg->data);CHKERRQ(ierr);
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   for (kk = 0; kk < nloc; kk++) {
65     for (ii = 0; ii < ndm; ii++) {
66       pc_gamg->data[ii*nloc + kk] =  coords[kk*ndm + ii];
67     }
68   }
69   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]);
70   pc_gamg->data_sz = arrsz;
71   PetscFunctionReturn(0);
72 }
73 
74 /* -------------------------------------------------------------------------- */
75 /*
76    PCSetData_GEO
77 
78   Input Parameter:
79    . pc -
80 */
81 PetscErrorCode PCSetData_GEO(PC pc, Mat m)
82 {
83   PetscFunctionBegin;
84   SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_PLIB,"GEO MG needs coordinates");
85 }
86 
87 /* -------------------------------------------------------------------------- */
88 /*
89    PCSetFromOptions_GEO
90 
91   Input Parameter:
92    . pc -
93 */
94 PetscErrorCode PCSetFromOptions_GEO(PetscOptionItems *PetscOptionsObject,PC pc)
95 {
96   PetscErrorCode ierr;
97 
98   PetscFunctionBegin;
99   ierr = PetscOptionsHead(PetscOptionsObject,"GAMG-GEO options");CHKERRQ(ierr);
100   {
101     /* -pc_gamg_sa_nsmooths */
102     /* pc_gamg_sa->smooths = 0; */
103     /* ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths", */
104     /*                        "smoothing steps for smoothed aggregation, usually 1 (0)", */
105     /*                        "PCGAMGSetNSmooths_AGG", */
106     /*                        pc_gamg_sa->smooths, */
107     /*                        &pc_gamg_sa->smooths, */
108     /*                        &flag);  */
109     /* CHKERRQ(ierr); */
110   }
111   ierr = PetscOptionsTail();CHKERRQ(ierr);
112   PetscFunctionReturn(0);
113 }
114 
115 /* -------------------------------------------------------------------------- */
116 /*
117  triangulateAndFormProl
118 
119    Input Parameter:
120    . selected_2 - list of selected local ID, includes selected ghosts
121    . data_stride -
122    . coords[2*data_stride] - column vector of local coordinates w/ ghosts
123    . nselected_1 - selected IDs that go with base (1) graph includes selected ghosts
124    . clid_lid_1[nselected_1] - lids of selected (c) nodes   ???????????
125    . agg_lists_1 - list of aggregates selected_1 vertices of aggregate unselected vertices
126    . crsGID[selected.size()] - global index for prolongation operator
127    . bs - block size
128   Output Parameter:
129    . a_Prol - prolongation operator
130    . a_worst_best - measure of worst missed fine vertex, 0 is no misses
131 */
132 static PetscErrorCode triangulateAndFormProl(IS selected_2,PetscInt data_stride,PetscReal coords[],PetscInt nselected_1,const PetscInt clid_lid_1[],const PetscCoarsenData *agg_lists_1,
133                                              const PetscInt crsGID[],PetscInt bs,Mat a_Prol,PetscReal *a_worst_best)
134 {
135 #if defined(PETSC_HAVE_TRIANGLE)
136   PetscErrorCode       ierr;
137   PetscInt             jj,tid,tt,idx,nselected_2;
138   struct triangulateio in,mid;
139   const PetscInt       *selected_idx_2;
140   PetscMPIInt          rank;
141   PetscInt             Istart,Iend,nFineLoc,myFine0;
142   int                  kk,nPlotPts,sid;
143   MPI_Comm             comm;
144   PetscReal            tm;
145 
146   PetscFunctionBegin;
147   ierr = PetscObjectGetComm((PetscObject)a_Prol,&comm);CHKERRQ(ierr);
148   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
149   ierr = ISGetSize(selected_2, &nselected_2);CHKERRQ(ierr);
150   if (nselected_2 == 1 || nselected_2 == 2) { /* 0 happens on idle processors */
151     *a_worst_best = 100.0; /* this will cause a stop, but not globalized (should not happen) */
152   } else *a_worst_best = 0.0;
153   ierr = MPIU_Allreduce(a_worst_best, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
154   if (tm > 0.0) {
155     *a_worst_best = 100.0;
156     PetscFunctionReturn(0);
157   }
158   ierr     = MatGetOwnershipRange(a_Prol, &Istart, &Iend);CHKERRQ(ierr);
159   nFineLoc = (Iend-Istart)/bs; myFine0 = Istart/bs;
160   nPlotPts = nFineLoc; /* locals */
161   /* traingle */
162   /* Define input points - in*/
163   in.numberofpoints          = nselected_2;
164   in.numberofpointattributes = 0;
165   /* get nselected points */
166   ierr = PetscMalloc1(2*nselected_2, &in.pointlist);CHKERRQ(ierr);
167   ierr = ISGetIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
168 
169   for (kk=0,sid=0; kk<nselected_2; kk++,sid += 2) {
170     PetscInt lid = selected_idx_2[kk];
171     in.pointlist[sid]   = coords[lid];
172     in.pointlist[sid+1] = coords[data_stride + lid];
173     if (lid>=nFineLoc) nPlotPts++;
174   }
175   if (sid != 2*nselected_2) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != 2*nselected_2 %D",sid,nselected_2);
176 
177   in.numberofsegments      = 0;
178   in.numberofedges         = 0;
179   in.numberofholes         = 0;
180   in.numberofregions       = 0;
181   in.trianglelist          = 0;
182   in.segmentmarkerlist     = 0;
183   in.pointattributelist    = 0;
184   in.pointmarkerlist       = 0;
185   in.triangleattributelist = 0;
186   in.trianglearealist      = 0;
187   in.segmentlist           = 0;
188   in.holelist              = 0;
189   in.regionlist            = 0;
190   in.edgelist              = 0;
191   in.edgemarkerlist        = 0;
192   in.normlist              = 0;
193 
194   /* triangulate */
195   mid.pointlist = 0;            /* Not needed if -N switch used. */
196   /* Not needed if -N switch used or number of point attributes is zero: */
197   mid.pointattributelist = 0;
198   mid.pointmarkerlist    = 0; /* Not needed if -N or -B switch used. */
199   mid.trianglelist       = 0;    /* Not needed if -E switch used. */
200   /* Not needed if -E switch used or number of triangle attributes is zero: */
201   mid.triangleattributelist = 0;
202   mid.neighborlist          = 0; /* Needed only if -n switch used. */
203   /* Needed only if segments are output (-p or -c) and -P not used: */
204   mid.segmentlist = 0;
205   /* Needed only if segments are output (-p or -c) and -P and -B not used: */
206   mid.segmentmarkerlist = 0;
207   mid.edgelist          = 0;    /* Needed only if -e switch used. */
208   mid.edgemarkerlist    = 0; /* Needed if -e used and -B not used. */
209   mid.numberoftriangles = 0;
210 
211   /* Triangulate the points.  Switches are chosen to read and write a  */
212   /*   PSLG (p), preserve the convex hull (c), number everything from  */
213   /*   zero (z), assign a regional attribute to each element (A), and  */
214   /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
215   /*   neighbor list (n).                                            */
216   if (nselected_2 != 0) { /* inactive processor */
217     char args[] = "npczQ"; /* c is needed ? */
218     triangulate(args, &in, &mid, (struct triangulateio*) NULL);
219     /* output .poly files for 'showme' */
220     if (!PETSC_TRUE) {
221       static int level = 1;
222       FILE       *file; char fname[32];
223 
224       sprintf(fname,"C%d_%d.poly",level,rank); file = fopen(fname, "w");
225       /*First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)>*/
226       fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0);
227       /*Following lines: <vertex #> <x> <y> */
228       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid += 2) {
229         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
230       }
231       /*One line: <# of segments> <# of boundary markers (0 or 1)> */
232       fprintf(file, "%d  %d\n",0,0);
233       /*Following lines: <segment #> <endpoint> <endpoint> [boundary marker] */
234       /* One line: <# of holes> */
235       fprintf(file, "%d\n",0);
236       /* Following lines: <hole #> <x> <y> */
237       /* Optional line: <# of regional attributes and/or area constraints> */
238       /* Optional following lines: <region #> <x> <y> <attribute> <maximum area> */
239       fclose(file);
240 
241       /* elems */
242       sprintf(fname,"C%d_%d.ele",level,rank); file = fopen(fname, "w");
243       /* First line: <# of triangles> <nodes per triangle> <# of attributes> */
244       fprintf(file, "%d %d %d\n",mid.numberoftriangles,3,0);
245       /* Remaining lines: <triangle #> <node> <node> <node> ... [attributes] */
246       for (kk=0,sid=0; kk<mid.numberoftriangles; kk++,sid += 3) {
247         fprintf(file, "%d %d %d %d\n",kk,mid.trianglelist[sid],mid.trianglelist[sid+1],mid.trianglelist[sid+2]);
248       }
249       fclose(file);
250 
251       sprintf(fname,"C%d_%d.node",level,rank); file = fopen(fname, "w");
252       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
253       /* fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0); */
254       fprintf(file, "%d  %d  %d  %d\n",nPlotPts,2,0,0);
255       /*Following lines: <vertex #> <x> <y> */
256       for (kk=0,sid=0; kk<in.numberofpoints; kk++,sid+=2) {
257         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
258       }
259 
260       sid /= 2;
261       for (jj=0; jj<nFineLoc; jj++) {
262         PetscBool sel = PETSC_TRUE;
263         for (kk=0; kk<nselected_2 && sel; kk++) {
264           PetscInt lid = selected_idx_2[kk];
265           if (lid == jj) sel = PETSC_FALSE;
266         }
267         if (sel) fprintf(file, "%d %e %e\n",sid++,coords[jj],coords[data_stride + jj]);
268       }
269       fclose(file);
270       if (sid != nPlotPts) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"sid %D != nPlotPts %D",sid,nPlotPts);
271       level++;
272     }
273   }
274 #if defined PETSC_GAMG_USE_LOG
275   ierr = PetscLogEventBegin(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
276 #endif
277   { /* form P - setup some maps */
278     PetscInt clid,mm,*nTri,*node_tri;
279 
280     ierr = PetscMalloc2(nselected_2, &node_tri,nselected_2, &nTri);CHKERRQ(ierr);
281 
282     /* need list of triangles on node */
283     for (kk=0; kk<nselected_2; kk++) nTri[kk] = 0;
284     for (tid=0,kk=0; tid<mid.numberoftriangles; tid++) {
285       for (jj=0; jj<3; jj++) {
286         PetscInt cid = mid.trianglelist[kk++];
287         if (nTri[cid] == 0) node_tri[cid] = tid;
288         nTri[cid]++;
289       }
290     }
291 #define EPS 1.e-12
292     /* find points and set prolongation */
293     for (mm = clid = 0; mm < nFineLoc; mm++) {
294       PetscBool ise;
295       ierr = PetscCDEmptyAt(agg_lists_1,mm,&ise);CHKERRQ(ierr);
296       if (!ise) {
297         const PetscInt lid = mm;
298         PetscScalar    AA[3][3];
299         PetscBLASInt   N=3,NRHS=1,LDA=3,IPIV[3],LDB=3,INFO;
300         PetscCDIntNd   *pos;
301 
302         ierr = PetscCDGetHeadPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
303         while (pos) {
304           PetscInt flid;
305           ierr = PetscCDIntNdGetID(pos, &flid);CHKERRQ(ierr);
306           ierr = PetscCDGetNextPos(agg_lists_1,lid,&pos);CHKERRQ(ierr);
307 
308           if (flid < nFineLoc) {  /* could be a ghost */
309             PetscInt       bestTID = -1; PetscReal best_alpha = 1.e10;
310             const PetscInt fgid    = flid + myFine0;
311             /* compute shape function for gid */
312             const PetscReal fcoord[3] = {coords[flid],coords[data_stride+flid],1.0};
313             PetscBool       haveit    =PETSC_FALSE; PetscScalar alpha[3]; PetscInt clids[3];
314 
315             /* look for it */
316             for (tid = node_tri[clid], jj=0;
317                  jj < 5 && !haveit && tid != -1;
318                  jj++) {
319               for (tt=0; tt<3; tt++) {
320                 PetscInt cid2 = mid.trianglelist[3*tid + tt];
321                 PetscInt lid2 = selected_idx_2[cid2];
322                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
323                 clids[tt] = cid2; /* store for interp */
324               }
325 
326               for (tt=0; tt<3; tt++) alpha[tt] = (PetscScalar)fcoord[tt];
327 
328               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
329               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
330               {
331                 PetscBool have=PETSC_TRUE;  PetscReal lowest=1.e10;
332                 for (tt = 0, idx = 0; tt < 3; tt++) {
333                   if (PetscRealPart(alpha[tt]) > (1.0+EPS) || PetscRealPart(alpha[tt]) < -EPS) have = PETSC_FALSE;
334                   if (PetscRealPart(alpha[tt]) < lowest) {
335                     lowest = PetscRealPart(alpha[tt]);
336                     idx    = tt;
337                   }
338                 }
339                 haveit = have;
340               }
341               tid = mid.neighborlist[3*tid + idx];
342             }
343 
344             if (!haveit) {
345               /* brute force */
346               for (tid=0; tid<mid.numberoftriangles && !haveit; tid++) {
347                 for (tt=0; tt<3; tt++) {
348                   PetscInt cid2 = mid.trianglelist[3*tid + tt];
349                   PetscInt lid2 = selected_idx_2[cid2];
350                   AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
351                   clids[tt] = cid2; /* store for interp */
352                 }
353                 for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
354                 /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
355                 PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
356                 {
357                   PetscBool have=PETSC_TRUE;  PetscReal worst=0.0, v;
358                   for (tt=0; tt<3 && have; tt++) {
359                     if (PetscRealPart(alpha[tt]) > 1.0+EPS || PetscRealPart(alpha[tt]) < -EPS) have=PETSC_FALSE;
360                     if ((v=PetscAbs(PetscRealPart(alpha[tt])-0.5)) > worst) worst = v;
361                   }
362                   if (worst < best_alpha) {
363                     best_alpha = worst; bestTID = tid;
364                   }
365                   haveit = have;
366                 }
367               }
368             }
369             if (!haveit) {
370               if (best_alpha > *a_worst_best) *a_worst_best = best_alpha;
371               /* use best one */
372               for (tt=0; tt<3; tt++) {
373                 PetscInt cid2 = mid.trianglelist[3*bestTID + tt];
374                 PetscInt lid2 = selected_idx_2[cid2];
375                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[data_stride + lid2]; AA[tt][2] = 1.0;
376                 clids[tt] = cid2; /* store for interp */
377               }
378               for (tt=0; tt<3; tt++) alpha[tt] = fcoord[tt];
379               /* SUBROUTINE DGESV(N, NRHS, A, LDA, IPIV, B, LDB, INFO) */
380               PetscStackCallBLAS("LAPACKgesv",LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO));
381             }
382 
383             /* put in row of P */
384             for (idx=0; idx<3; idx++) {
385               PetscScalar shp = alpha[idx];
386               if (PetscAbs(PetscRealPart(shp)) > 1.e-6) {
387                 PetscInt cgid = crsGID[clids[idx]];
388                 PetscInt jj   = cgid*bs, ii = fgid*bs; /* need to gloalize */
389                 for (tt=0; tt < bs; tt++, ii++, jj++) {
390                   ierr = MatSetValues(a_Prol,1,&ii,1,&jj,&shp,INSERT_VALUES);CHKERRQ(ierr);
391                 }
392               }
393             }
394           }
395         } /* aggregates iterations */
396         clid++;
397       } /* a coarse agg */
398     } /* for all fine nodes */
399 
400     ierr = ISRestoreIndices(selected_2, &selected_idx_2);CHKERRQ(ierr);
401     ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
402     ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
403 
404     ierr = PetscFree2(node_tri,nTri);CHKERRQ(ierr);
405   }
406 #if defined PETSC_GAMG_USE_LOG
407   ierr = PetscLogEventEnd(petsc_gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
408 #endif
409   free(mid.trianglelist);
410   free(mid.neighborlist);
411   ierr = PetscFree(in.pointlist);CHKERRQ(ierr);
412   PetscFunctionReturn(0);
413 #else
414   SETERRQ(PetscObjectComm((PetscObject)a_Prol),PETSC_ERR_PLIB,"configure with TRIANGLE to use geometric MG");
415 #endif
416 }
417 /* -------------------------------------------------------------------------- */
418 /*
419    getGIDsOnSquareGraph - square graph, get
420 
421    Input Parameter:
422    . nselected_1 - selected local indices (includes ghosts in input Gmat1)
423    . clid_lid_1 - [nselected_1] lids of selected nodes
424    . Gmat1 - graph that goes with 'selected_1'
425    Output Parameter:
426    . a_selected_2 - selected local indices (includes ghosts in output a_Gmat_2)
427    . a_Gmat_2 - graph that is squared of 'Gmat_1'
428    . a_crsGID[a_selected_2.size()] - map of global IDs of coarse grid nodes
429 */
430 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)
431 {
432   PetscErrorCode ierr;
433   PetscMPIInt    size;
434   PetscInt       *crsGID, kk,my0,Iend,nloc;
435   MPI_Comm       comm;
436 
437   PetscFunctionBegin;
438   ierr = PetscObjectGetComm((PetscObject)Gmat1,&comm);CHKERRQ(ierr);
439   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
440   ierr = MatGetOwnershipRange(Gmat1,&my0,&Iend);CHKERRQ(ierr); /* AIJ */
441   nloc = Iend - my0; /* this does not change */
442 
443   if (size == 1) { /* not much to do in serial */
444     ierr = PetscMalloc1(nselected_1, &crsGID);CHKERRQ(ierr);
445     for (kk=0; kk<nselected_1; kk++) crsGID[kk] = kk;
446     *a_Gmat_2 = 0;
447     ierr      = ISCreateGeneral(PETSC_COMM_SELF,nselected_1,clid_lid_1,PETSC_COPY_VALUES,a_selected_2);CHKERRQ(ierr);
448   } else {
449     PetscInt    idx,num_fine_ghosts,num_crs_ghost,myCrs0;
450     Mat_MPIAIJ  *mpimat2;
451     Mat         Gmat2;
452     Vec         locState;
453     PetscScalar *cpcol_state;
454 
455     /* scan my coarse zero gid, set 'lid_state' with coarse GID */
456     kk = nselected_1;
457     ierr = MPI_Scan(&kk, &myCrs0, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr);
458     myCrs0 -= nselected_1;
459 
460     if (a_Gmat_2) { /* output */
461       /* grow graph to get wider set of selected vertices to cover fine grid, invalidates 'llist' */
462       ierr      = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2);CHKERRQ(ierr);
463       *a_Gmat_2 = Gmat2; /* output */
464     } else Gmat2 = Gmat1;  /* use local to get crsGIDs at least */
465     /* get coarse grid GIDS for selected (locals and ghosts) */
466     mpimat2 = (Mat_MPIAIJ*)Gmat2->data;
467     ierr    = MatCreateVecs(Gmat2, &locState, 0);CHKERRQ(ierr);
468     ierr    = VecSet(locState, (PetscScalar)(PetscReal)(-1));CHKERRQ(ierr); /* set with UNKNOWN state */
469     for (kk=0; kk<nselected_1; kk++) {
470       PetscInt    fgid = clid_lid_1[kk] + my0;
471       PetscScalar v    = (PetscScalar)(kk+myCrs0);
472       ierr = VecSetValues(locState, 1, &fgid, &v, INSERT_VALUES);CHKERRQ(ierr); /* set with PID */
473     }
474     ierr = VecAssemblyBegin(locState);CHKERRQ(ierr);
475     ierr = VecAssemblyEnd(locState);CHKERRQ(ierr);
476     ierr = VecScatterBegin(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
477     ierr =   VecScatterEnd(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
478     ierr = VecGetLocalSize(mpimat2->lvec, &num_fine_ghosts);CHKERRQ(ierr);
479     ierr = VecGetArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
480     for (kk=0,num_crs_ghost=0; kk<num_fine_ghosts; kk++) {
481       if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) num_crs_ghost++;
482     }
483     ierr = PetscMalloc1(nselected_1+num_crs_ghost, &crsGID);CHKERRQ(ierr); /* output */
484     {
485       PetscInt *selected_set;
486       ierr = PetscMalloc1(nselected_1+num_crs_ghost, &selected_set);CHKERRQ(ierr);
487       /* do ghost of 'crsGID' */
488       for (kk=0,idx=nselected_1; kk<num_fine_ghosts; kk++) {
489         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
490           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
491           selected_set[idx] = nloc + kk;
492           crsGID[idx++]     = cgid;
493         }
494       }
495       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);
496       ierr = VecRestoreArray(mpimat2->lvec, &cpcol_state);CHKERRQ(ierr);
497       /* do locals in 'crsGID' */
498       ierr = VecGetArray(locState, &cpcol_state);CHKERRQ(ierr);
499       for (kk=0,idx=0; kk<nloc; kk++) {
500         if ((PetscInt)PetscRealPart(cpcol_state[kk]) != -1) {
501           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
502           selected_set[idx] = kk;
503           crsGID[idx++]     = cgid;
504         }
505       }
506       if (idx != nselected_1) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"idx %D != nselected_1 %D",idx,nselected_1);
507       ierr = VecRestoreArray(locState, &cpcol_state);CHKERRQ(ierr);
508 
509       if (a_selected_2 != 0) { /* output */
510         ierr = ISCreateGeneral(PETSC_COMM_SELF,(nselected_1+num_crs_ghost),selected_set,PETSC_OWN_POINTER,a_selected_2);CHKERRQ(ierr);
511       } else {
512         ierr = PetscFree(selected_set);CHKERRQ(ierr);
513       }
514     }
515     ierr = VecDestroy(&locState);CHKERRQ(ierr);
516   }
517   *a_crsGID = crsGID; /* output */
518   PetscFunctionReturn(0);
519 }
520 
521 /* -------------------------------------------------------------------------- */
522 /*
523    PCGAMGGraph_GEO
524 
525   Input Parameter:
526    . pc - this
527    . Amat - matrix on this fine level
528   Output Parameter:
529    . a_Gmat
530 */
531 PetscErrorCode PCGAMGGraph_GEO(PC pc,Mat Amat,Mat *a_Gmat)
532 {
533   PetscErrorCode  ierr;
534   PC_MG           *mg      = (PC_MG*)pc->data;
535   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
536   const PetscReal vfilter  = pc_gamg->threshold[0];
537   MPI_Comm        comm;
538   Mat             Gmat;
539   PetscBool       set,flg,symm;
540 
541   PetscFunctionBegin;
542   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
543   ierr = PetscLogEventBegin(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
544 
545   ierr = MatIsSymmetricKnown(Amat, &set, &flg);CHKERRQ(ierr);
546   symm = (PetscBool)!(set && flg);
547 
548   ierr = PCGAMGCreateGraph(Amat, &Gmat);CHKERRQ(ierr);
549   ierr = PCGAMGFilterGraph(&Gmat, vfilter, symm);CHKERRQ(ierr);
550 
551   *a_Gmat = Gmat;
552   ierr = PetscLogEventEnd(PC_GAMGGraph_GEO,0,0,0,0);CHKERRQ(ierr);
553   PetscFunctionReturn(0);
554 }
555 
556 /* -------------------------------------------------------------------------- */
557 /*
558    PCGAMGCoarsen_GEO
559 
560   Input Parameter:
561    . a_pc - this
562    . a_Gmat - graph
563   Output Parameter:
564    . a_llist_parent - linked list from selected indices for data locality only
565 */
566 PetscErrorCode PCGAMGCoarsen_GEO(PC a_pc,Mat *a_Gmat,PetscCoarsenData **a_llist_parent)
567 {
568   PetscErrorCode ierr;
569   PetscInt       Istart,Iend,nloc,kk,Ii,ncols;
570   IS             perm;
571   GAMGNode       *gnodes;
572   PetscInt       *permute;
573   Mat            Gmat  = *a_Gmat;
574   MPI_Comm       comm;
575   MatCoarsen     crs;
576 
577   PetscFunctionBegin;
578   ierr = PetscObjectGetComm((PetscObject)a_pc,&comm);CHKERRQ(ierr);
579   ierr = PetscLogEventBegin(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
580   ierr = MatGetOwnershipRange(Gmat, &Istart, &Iend);CHKERRQ(ierr);
581   nloc = (Iend-Istart);
582 
583   /* create random permutation with sort for geo-mg */
584   ierr = PetscMalloc1(nloc, &gnodes);CHKERRQ(ierr);
585   ierr = PetscMalloc1(nloc, &permute);CHKERRQ(ierr);
586 
587   for (Ii=Istart; Ii<Iend; Ii++) { /* locals only? */
588     ierr = MatGetRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
589     {
590       PetscInt lid = Ii - Istart;
591       gnodes[lid].lid    = lid;
592       gnodes[lid].degree = ncols;
593     }
594     ierr = MatRestoreRow(Gmat,Ii,&ncols,0,0);CHKERRQ(ierr);
595   }
596   if (PETSC_TRUE) {
597     PetscRandom  rand;
598     PetscBool    *bIndexSet;
599     PetscReal    rr;
600     PetscInt     iSwapIndex;
601 
602     ierr = PetscRandomCreate(comm,&rand);CHKERRQ(ierr);
603     ierr = PetscCalloc1(nloc, &bIndexSet);CHKERRQ(ierr);
604     for (Ii = 0; Ii < nloc; Ii++) {
605       ierr = PetscRandomGetValueReal(rand,&rr);CHKERRQ(ierr);
606       iSwapIndex = (PetscInt) (rr*nloc);
607       if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii) {
608         GAMGNode iTemp = gnodes[iSwapIndex];
609         gnodes[iSwapIndex]    = gnodes[Ii];
610         gnodes[Ii]            = iTemp;
611         bIndexSet[Ii]         = PETSC_TRUE;
612         bIndexSet[iSwapIndex] = PETSC_TRUE;
613       }
614     }
615     ierr = PetscRandomDestroy(&rand);CHKERRQ(ierr);
616     ierr = PetscFree(bIndexSet);CHKERRQ(ierr);
617   }
618   /* only sort locals */
619   qsort(gnodes, nloc, sizeof(GAMGNode), petsc_geo_mg_compare);
620   /* create IS of permutation */
621   for (kk=0; kk<nloc; kk++) permute[kk] = gnodes[kk].lid; /* locals only */
622   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_OWN_POINTER, &perm);CHKERRQ(ierr);
623 
624   ierr = PetscFree(gnodes);CHKERRQ(ierr);
625 
626   /* get MIS aggs */
627 
628   ierr = MatCoarsenCreate(comm, &crs);CHKERRQ(ierr);
629   ierr = MatCoarsenSetType(crs, MATCOARSENMIS);CHKERRQ(ierr);
630   ierr = MatCoarsenSetGreedyOrdering(crs, perm);CHKERRQ(ierr);
631   ierr = MatCoarsenSetAdjacency(crs, Gmat);CHKERRQ(ierr);
632   ierr = MatCoarsenSetStrictAggs(crs, PETSC_FALSE);CHKERRQ(ierr);
633   ierr = MatCoarsenApply(crs);CHKERRQ(ierr);
634   ierr = MatCoarsenGetData(crs, a_llist_parent);CHKERRQ(ierr);
635   ierr = MatCoarsenDestroy(&crs);CHKERRQ(ierr);
636 
637   ierr = ISDestroy(&perm);CHKERRQ(ierr);
638   ierr = PetscLogEventEnd(PC_GAMGCoarsen_GEO,0,0,0,0);CHKERRQ(ierr);
639   PetscFunctionReturn(0);
640 }
641 
642 /* -------------------------------------------------------------------------- */
643 /*
644  PCGAMGProlongator_GEO
645 
646  Input Parameter:
647  . pc - this
648  . Amat - matrix on this fine level
649  . Graph - used to get ghost data for nodes in
650  . selected_1 - [nselected]
651  . agg_lists - [nselected]
652  Output Parameter:
653  . a_P_out - prolongation operator to the next level
654  */
655 PetscErrorCode PCGAMGProlongator_GEO(PC pc,Mat Amat,Mat Gmat,PetscCoarsenData *agg_lists,Mat *a_P_out)
656 {
657   PC_MG          *mg      = (PC_MG*)pc->data;
658   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
659   const PetscInt dim      = pc_gamg->data_cell_cols, data_cols = pc_gamg->data_cell_cols;
660   PetscErrorCode ierr;
661   PetscInt       Istart,Iend,nloc,my0,jj,kk,ncols,nLocalSelected,bs,*clid_flid;
662   Mat            Prol;
663   PetscMPIInt    rank, size;
664   MPI_Comm       comm;
665   IS             selected_2,selected_1;
666   const PetscInt *selected_idx;
667   MatType        mtype;
668 
669   PetscFunctionBegin;
670   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
671   ierr = PetscLogEventBegin(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
672   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
673   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
674   ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
675   ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
676   nloc = (Iend-Istart)/bs; my0 = Istart/bs;
677   if ((Iend-Istart) % bs) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"(Iend %D - Istart %D) % bs %D",Iend,Istart,bs);
678 
679   /* get 'nLocalSelected' */
680   ierr = PetscCDGetMIS(agg_lists, &selected_1);CHKERRQ(ierr);
681   ierr = ISGetSize(selected_1, &jj);CHKERRQ(ierr);
682   ierr = PetscMalloc1(jj, &clid_flid);CHKERRQ(ierr);
683   ierr = ISGetIndices(selected_1, &selected_idx);CHKERRQ(ierr);
684   for (kk=0,nLocalSelected=0; kk<jj; kk++) {
685     PetscInt lid = selected_idx[kk];
686     if (lid<nloc) {
687       ierr = MatGetRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
688       if (ncols>1) clid_flid[nLocalSelected++] = lid; /* fiter out singletons */
689       ierr = MatRestoreRow(Gmat,lid+my0,&ncols,0,0);CHKERRQ(ierr);
690     }
691   }
692   ierr = ISRestoreIndices(selected_1, &selected_idx);CHKERRQ(ierr);
693   ierr = ISDestroy(&selected_1);CHKERRQ(ierr); /* this is selected_1 in serial */
694 
695   /* create prolongator  matrix */
696   ierr = MatGetType(Amat,&mtype);CHKERRQ(ierr);
697   ierr = MatCreate(comm, &Prol);CHKERRQ(ierr);
698   ierr = MatSetSizes(Prol,nloc*bs,nLocalSelected*bs,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
699   ierr = MatSetBlockSizes(Prol, bs, bs);CHKERRQ(ierr);
700   ierr = MatSetType(Prol, mtype);CHKERRQ(ierr);
701   ierr = MatSeqAIJSetPreallocation(Prol,3*data_cols,NULL);CHKERRQ(ierr);
702   ierr = MatMPIAIJSetPreallocation(Prol,3*data_cols,NULL,3*data_cols,NULL);CHKERRQ(ierr);
703 
704   /* can get all points "removed" - but not on geomg */
705   ierr =  MatGetSize(Prol, &kk, &jj);CHKERRQ(ierr);
706   if (!jj) {
707     ierr = PetscInfo(pc,"ERROE: no selected points on coarse grid\n");CHKERRQ(ierr);
708     ierr = PetscFree(clid_flid);CHKERRQ(ierr);
709     ierr = MatDestroy(&Prol);CHKERRQ(ierr);
710     *a_P_out = NULL;  /* out */
711     PetscFunctionReturn(0);
712   }
713 
714   {
715     PetscReal *coords;
716     PetscInt  data_stride;
717     PetscInt  *crsGID = NULL;
718     Mat       Gmat2;
719 
720     if (dim != data_cols) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"dim %D != data_cols %D",dim,data_cols);
721     /* grow ghost data for better coarse grid cover of fine grid */
722 #if defined PETSC_GAMG_USE_LOG
723     ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
724 #endif
725     /* messy method, squares graph and gets some data */
726     ierr = getGIDsOnSquareGraph(nLocalSelected, clid_flid, Gmat, &selected_2, &Gmat2, &crsGID);CHKERRQ(ierr);
727     /* llist is now not valid wrt squared graph, but will work as iterator in 'triangulateAndFormProl' */
728 #if defined PETSC_GAMG_USE_LOG
729     ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
730 #endif
731     /* create global vector of coorindates in 'coords' */
732     if (size > 1) {
733       ierr = PCGAMGGetDataWithGhosts(Gmat2, dim, pc_gamg->data, &data_stride, &coords);CHKERRQ(ierr);
734     } else {
735       coords      = (PetscReal*)pc_gamg->data;
736       data_stride = pc_gamg->data_sz/pc_gamg->data_cell_cols;
737     }
738     ierr = MatDestroy(&Gmat2);CHKERRQ(ierr);
739 
740     /* triangulate */
741     if (dim == 2) {
742       PetscReal metric,tm;
743 #if defined PETSC_GAMG_USE_LOG
744       ierr = PetscLogEventBegin(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
745 #endif
746       ierr = triangulateAndFormProl(selected_2, data_stride, coords,nLocalSelected, clid_flid, agg_lists, crsGID, bs, Prol, &metric);CHKERRQ(ierr);
747 #if defined PETSC_GAMG_USE_LOG
748       ierr = PetscLogEventEnd(petsc_gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
749 #endif
750       ierr = PetscFree(crsGID);CHKERRQ(ierr);
751 
752       /* clean up and create coordinates for coarse grid (output) */
753       if (size > 1) ierr = PetscFree(coords);CHKERRQ(ierr);
754 
755       ierr = MPIU_Allreduce(&metric, &tm, 1, MPIU_REAL, MPIU_MAX, comm);CHKERRQ(ierr);
756       if (tm > 1.) { /* needs to be globalized - should not happen */
757         ierr = PetscInfo1(pc," failed metric for coarse grid %e\n",(double)tm);CHKERRQ(ierr);
758         ierr = MatDestroy(&Prol);CHKERRQ(ierr);
759       } else if (metric > .0) {
760         ierr = PetscInfo1(pc,"worst metric for coarse grid = %e\n",(double)metric);CHKERRQ(ierr);
761       }
762     } else SETERRQ(comm,PETSC_ERR_PLIB,"3D not implemented for 'geo' AMG");
763     { /* create next coords - output */
764       PetscReal *crs_crds;
765       ierr = PetscMalloc1(dim*nLocalSelected, &crs_crds);CHKERRQ(ierr);
766       for (kk=0; kk<nLocalSelected; kk++) { /* grab local select nodes to promote - output */
767         PetscInt lid = clid_flid[kk];
768         for (jj=0; jj<dim; jj++) crs_crds[jj*nLocalSelected + kk] = pc_gamg->data[jj*nloc + lid];
769       }
770 
771       ierr             = PetscFree(pc_gamg->data);CHKERRQ(ierr);
772       pc_gamg->data    = crs_crds; /* out */
773       pc_gamg->data_sz = dim*nLocalSelected;
774     }
775     ierr = ISDestroy(&selected_2);CHKERRQ(ierr);
776   }
777 
778   *a_P_out = Prol;  /* out */
779   ierr     = PetscFree(clid_flid);CHKERRQ(ierr);
780   ierr = PetscLogEventEnd(PC_GAMGProlongator_GEO,0,0,0,0);CHKERRQ(ierr);
781   PetscFunctionReturn(0);
782 }
783 
784 static PetscErrorCode PCDestroy_GAMG_GEO(PC pc)
785 {
786   PetscErrorCode ierr;
787 
788   PetscFunctionBegin;
789   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",NULL);CHKERRQ(ierr);
790   PetscFunctionReturn(0);
791 }
792 
793 /* -------------------------------------------------------------------------- */
794 /*
795  PCCreateGAMG_GEO
796 
797   Input Parameter:
798    . pc -
799 */
800 PetscErrorCode  PCCreateGAMG_GEO(PC pc)
801 {
802   PetscErrorCode ierr;
803   PC_MG          *mg      = (PC_MG*)pc->data;
804   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
805 
806   PetscFunctionBegin;
807   pc_gamg->ops->setfromoptions = PCSetFromOptions_GEO;
808   pc_gamg->ops->destroy        = PCDestroy_GAMG_GEO;
809   /* reset does not do anything; setup not virtual */
810 
811   /* set internal function pointers */
812   pc_gamg->ops->graph             = PCGAMGGraph_GEO;
813   pc_gamg->ops->coarsen           = PCGAMGCoarsen_GEO;
814   pc_gamg->ops->prolongator       = PCGAMGProlongator_GEO;
815   pc_gamg->ops->optprolongator    = NULL;
816   pc_gamg->ops->createdefaultdata = PCSetData_GEO;
817 
818   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCSetCoordinates_C",PCSetCoordinates_GEO);CHKERRQ(ierr);
819   PetscFunctionReturn(0);
820 }
821