xref: /petsc/src/ksp/pc/impls/gamg/geo.c (revision c8b0795c72925863ad731cd6ce6065cb75fdfda2)
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 <private/kspimpl.h>
7 
8 #if defined(PETSC_HAVE_TRIANGLE)
9 #define REAL PetscReal
10 #include <triangle.h>
11 #endif
12 
13 #include <assert.h>
14 #include <petscblaslapack.h>
15 
16 /* Private context for the GAMG preconditioner */
17 typedef struct{
18   PetscInt       lid;      /* local vertex index */
19   PetscInt       degree;   /* vertex degree */
20 } GAMGNode;
21 int 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 EXTERN_C_BEGIN
34 #undef __FUNCT__
35 #define __FUNCT__ "PCSetCoordinates_GEO"
36 PetscErrorCode PCSetCoordinates_GEO( PC pc, PetscInt ndm, PetscReal *coords )
37 {
38   PC_MG          *mg = (PC_MG*)pc->data;
39   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
40   PetscErrorCode ierr;
41   PetscInt       arrsz,bs,my0,kk,ii,nloc,Iend;
42   Mat            Amat = pc->pmat;
43 
44   PetscFunctionBegin;
45   PetscValidHeaderSpecific( Amat, MAT_CLASSID, 1 );
46   ierr  = MatGetBlockSize( Amat, &bs );               CHKERRQ( ierr );
47   ierr  = MatGetOwnershipRange( Amat, &my0, &Iend ); CHKERRQ(ierr);
48   nloc = (Iend-my0)/bs;
49   if((Iend-my0)%bs!=0) SETERRQ1(((PetscObject)Amat)->comm,PETSC_ERR_ARG_WRONG, "Bad local size %d.",nloc);
50 
51   pc_gamg->data_cell_rows = 1;
52   if( coords==0 && nloc > 0 ) {
53     SETERRQ(((PetscObject)Amat)->comm,PETSC_ERR_ARG_WRONG, "Need coordinates for pc_gamg_type 'geo'.");
54   }
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 = PetscMalloc((arrsz+1)*sizeof(PetscReal), &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   assert(pc_gamg->data[arrsz] == -99.);
73 
74   pc_gamg->data_sz = arrsz;
75 
76   PetscFunctionReturn(0);
77 }
78 EXTERN_C_END
79 
80 /* -------------------------------------------------------------------------- */
81 /*
82    PCSetData_GEO
83 
84   Input Parameter:
85    . pc -
86 */
87 #undef __FUNCT__
88 #define __FUNCT__ "PCSetData_GEO"
89 PetscErrorCode PCSetData_GEO( PC pc )
90 {
91   PetscFunctionBegin;
92   SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_LIB,"GEO MG needs coordinates");
93 }
94 
95 /* -------------------------------------------------------------------------- */
96 /*
97    PCSetFromOptions_GEO
98 
99   Input Parameter:
100    . pc -
101 */
102 #undef __FUNCT__
103 #define __FUNCT__ "PCSetFromOptions_GEO"
104 PetscErrorCode PCSetFromOptions_GEO( PC pc )
105 {
106   PetscErrorCode  ierr;
107   PC_MG           *mg = (PC_MG*)pc->data;
108   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
109 
110   PetscFunctionBegin;
111   ierr = PetscOptionsHead("GAMG-GEO options"); CHKERRQ(ierr);
112   {
113     /* -pc_gamg_sa_nsmooths */
114     /* pc_gamg_sa->smooths = 0; */
115     /* ierr = PetscOptionsInt("-pc_gamg_agg_nsmooths", */
116     /*                        "smoothing steps for smoothed aggregation, usually 1 (0)", */
117     /*                        "PCGAMGSetNSmooths_AGG", */
118     /*                        pc_gamg_sa->smooths, */
119     /*                        &pc_gamg_sa->smooths, */
120     /*                        &flag);  */
121     /* CHKERRQ(ierr); */
122   }
123   ierr = PetscOptionsTail();CHKERRQ(ierr);
124 
125   /* call base class */
126   ierr = PCSetFromOptions_GAMG( pc ); CHKERRQ(ierr);
127 
128   if( pc_gamg->verbose ) {
129     PetscPrintf(PETSC_COMM_WORLD,"[%d]%s done\n",0,__FUNCT__);
130   }
131 
132   PetscFunctionReturn(0);
133 }
134 
135 /* -------------------------------------------------------------------------- */
136 /*
137  triangulateAndFormProl
138 
139    Input Parameter:
140    . selected_2 - list of selected local ID, includes selected ghosts
141    . nnodes -
142    . coords[2*nnodes] - column vector of local coordinates w/ ghosts
143    . selected_1 - selected IDs that go with base (1) graph
144    . locals_llist - linked list with (some) locality info of base graph
145    . crsGID[selected.size()] - global index for prolongation operator
146    . bs - block size
147   Output Parameter:
148    . a_Prol - prolongation operator
149    . a_worst_best - measure of worst missed fine vertex, 0 is no misses
150 */
151 #undef __FUNCT__
152 #define __FUNCT__ "triangulateAndFormProl"
153 PetscErrorCode triangulateAndFormProl( IS  selected_2, /* list of selected local ID, includes selected ghosts */
154 				       const PetscInt nnodes,
155                                        const PetscReal coords[], /* column vector of local coordinates w/ ghosts */
156                                        IS  selected_1, /* list of selected local ID, includes selected ghosts */
157                                        IS  locals_llist, /* linked list from selected vertices of aggregate unselected vertices */
158 				       const PetscInt crsGID[],
159                                        const PetscInt bs,
160                                        Mat a_Prol, /* prolongation operator (output) */
161                                        PetscReal *a_worst_best /* measure of worst missed fine vertex, 0 is no misses */
162                                        )
163 {
164 #if defined(PETSC_HAVE_TRIANGLE)
165   PetscErrorCode       ierr;
166   PetscInt             jj,tid,tt,idx,nselected_1,nselected_2;
167   struct triangulateio in,mid;
168   const PetscInt      *selected_idx_1,*selected_idx_2,*llist_idx;
169   PetscMPIInt          mype,npe;
170   PetscInt             Istart,Iend,nFineLoc,myFine0;
171   int kk,nPlotPts,sid;
172   MPI_Comm       wcomm = ((PetscObject)a_Prol)->comm;
173   PetscReal      tm;
174   PetscFunctionBegin;
175 
176   ierr = MPI_Comm_rank(wcomm,&mype);    CHKERRQ(ierr);
177   ierr = MPI_Comm_size(wcomm,&npe);     CHKERRQ(ierr);
178   ierr = ISGetSize( selected_1, &nselected_1 );        CHKERRQ(ierr);
179   ierr = ISGetSize( selected_2, &nselected_2 );        CHKERRQ(ierr);
180   if(nselected_2 == 1 || nselected_2 == 2 ){ /* 0 happens on idle processors */
181     *a_worst_best = 100.0; /* this will cause a stop, but not globalized (should not happen) */
182   }
183   else *a_worst_best = 0.0;
184   ierr = MPI_Allreduce( a_worst_best, &tm, 1, MPIU_REAL, MPIU_MAX, wcomm );  CHKERRQ(ierr);
185   if( tm > 0.0 ) {
186     *a_worst_best = 100.0;
187     PetscFunctionReturn(0);
188   }
189   ierr = MatGetOwnershipRange( a_Prol, &Istart, &Iend );  CHKERRQ(ierr);
190   nFineLoc = (Iend-Istart)/bs; myFine0 = Istart/bs;
191   nPlotPts = nFineLoc; /* locals */
192   /* traingle */
193   /* Define input points - in*/
194   in.numberofpoints = nselected_2;
195   in.numberofpointattributes = 0;
196   /* get nselected points */
197   ierr = PetscMalloc( 2*(nselected_2)*sizeof(REAL), &in.pointlist ); CHKERRQ(ierr);
198   ierr = ISGetIndices( selected_2, &selected_idx_2 );     CHKERRQ(ierr);
199 
200   for(kk=0,sid=0;kk<nselected_2;kk++,sid += 2){
201     PetscInt lid = selected_idx_2[kk];
202     in.pointlist[sid] = coords[lid];
203     in.pointlist[sid+1] = coords[nnodes + lid];
204     if(lid>=nFineLoc) nPlotPts++;
205   }
206   assert(sid==2*nselected_2);
207 
208   in.numberofsegments = 0;
209   in.numberofedges = 0;
210   in.numberofholes = 0;
211   in.numberofregions = 0;
212   in.trianglelist = 0;
213   in.segmentmarkerlist = 0;
214   in.pointattributelist = 0;
215   in.pointmarkerlist = 0;
216   in.triangleattributelist = 0;
217   in.trianglearealist = 0;
218   in.segmentlist = 0;
219   in.holelist = 0;
220   in.regionlist = 0;
221   in.edgelist = 0;
222   in.edgemarkerlist = 0;
223   in.normlist = 0;
224   /* triangulate */
225   mid.pointlist = 0;            /* Not needed if -N switch used. */
226   /* Not needed if -N switch used or number of point attributes is zero: */
227   mid.pointattributelist = 0;
228   mid.pointmarkerlist = 0; /* Not needed if -N or -B switch used. */
229   mid.trianglelist = 0;          /* Not needed if -E switch used. */
230   /* Not needed if -E switch used or number of triangle attributes is zero: */
231   mid.triangleattributelist = 0;
232   mid.neighborlist = 0;         /* Needed only if -n switch used. */
233   /* Needed only if segments are output (-p or -c) and -P not used: */
234   mid.segmentlist = 0;
235   /* Needed only if segments are output (-p or -c) and -P and -B not used: */
236   mid.segmentmarkerlist = 0;
237   mid.edgelist = 0;             /* Needed only if -e switch used. */
238   mid.edgemarkerlist = 0;   /* Needed if -e used and -B not used. */
239   mid.numberoftriangles = 0;
240 
241   /* Triangulate the points.  Switches are chosen to read and write a  */
242   /*   PSLG (p), preserve the convex hull (c), number everything from  */
243   /*   zero (z), assign a regional attribute to each element (A), and  */
244   /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
245   /*   neighbor list (n).                                            */
246   if(nselected_2 != 0){ /* inactive processor */
247     char args[] = "npczQ"; /* c is needed ? */
248     triangulate(args, &in, &mid, (struct triangulateio *) NULL );
249     /* output .poly files for 'showme' */
250     if( !PETSC_TRUE ) {
251       static int level = 1;
252       FILE *file; char fname[32];
253 
254       sprintf(fname,"C%d_%d.poly",level,mype); file = fopen(fname, "w");
255       /*First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)>*/
256       fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0);
257       /*Following lines: <vertex #> <x> <y> */
258       for(kk=0,sid=0;kk<in.numberofpoints;kk++,sid += 2){
259         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
260       }
261       /*One line: <# of segments> <# of boundary markers (0 or 1)> */
262       fprintf(file, "%d  %d\n",0,0);
263       /*Following lines: <segment #> <endpoint> <endpoint> [boundary marker] */
264       /* One line: <# of holes> */
265       fprintf(file, "%d\n",0);
266       /* Following lines: <hole #> <x> <y> */
267       /* Optional line: <# of regional attributes and/or area constraints> */
268       /* Optional following lines: <region #> <x> <y> <attribute> <maximum area> */
269       fclose(file);
270 
271       /* elems */
272       sprintf(fname,"C%d_%d.ele",level,mype); file = fopen(fname, "w");
273       /* First line: <# of triangles> <nodes per triangle> <# of attributes> */
274       fprintf(file, "%d %d %d\n",mid.numberoftriangles,3,0);
275       /* Remaining lines: <triangle #> <node> <node> <node> ... [attributes] */
276       for(kk=0,sid=0;kk<mid.numberoftriangles;kk++,sid += 3){
277         fprintf(file, "%d %d %d %d\n",kk,mid.trianglelist[sid],mid.trianglelist[sid+1],mid.trianglelist[sid+2]);
278       }
279       fclose(file);
280 
281       sprintf(fname,"C%d_%d.node",level,mype); file = fopen(fname, "w");
282       /* First line: <# of vertices> <dimension (must be 2)> <# of attributes> <# of boundary markers (0 or 1)> */
283       /* fprintf(file, "%d  %d  %d  %d\n",in.numberofpoints,2,0,0); */
284       fprintf(file, "%d  %d  %d  %d\n",nPlotPts,2,0,0);
285       /*Following lines: <vertex #> <x> <y> */
286       for(kk=0,sid=0;kk<in.numberofpoints;kk++,sid+=2){
287         fprintf(file, "%d %e %e\n",kk,in.pointlist[sid],in.pointlist[sid+1]);
288       }
289 
290       sid /= 2;
291       for(jj=0;jj<nFineLoc;jj++){
292         PetscBool sel = PETSC_TRUE;
293         for( kk=0 ; kk<nselected_2 && sel ; kk++ ){
294           PetscInt lid = selected_idx_2[kk];
295           if( lid == jj ) sel = PETSC_FALSE;
296         }
297         if( sel ) {
298           fprintf(file, "%d %e %e\n",sid++,coords[jj],coords[nnodes + jj]);
299         }
300       }
301       fclose(file);
302       assert(sid==nPlotPts);
303       level++;
304     }
305   }
306 #if defined PETSC_USE_LOG
307   ierr = PetscLogEventBegin(gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
308 #endif
309   { /* form P - setup some maps */
310     PetscInt clid_iterator;
311     PetscInt *nTri, *node_tri;
312 
313     ierr = PetscMalloc( nselected_2*sizeof(PetscInt), &node_tri ); CHKERRQ(ierr);
314     ierr = PetscMalloc( nselected_2*sizeof(PetscInt), &nTri ); CHKERRQ(ierr);
315 
316     /* need list of triangles on node */
317     for(kk=0;kk<nselected_2;kk++) nTri[kk] = 0;
318     for(tid=0,kk=0;tid<mid.numberoftriangles;tid++){
319       for(jj=0;jj<3;jj++) {
320         PetscInt cid = mid.trianglelist[kk++];
321         if( nTri[cid] == 0 ) node_tri[cid] = tid;
322         nTri[cid]++;
323       }
324     }
325 #define EPS 1.e-12
326     /* find points and set prolongation */
327     ierr = ISGetIndices( selected_1, &selected_idx_1 );     CHKERRQ(ierr);
328     ierr = ISGetIndices( locals_llist, &llist_idx );     CHKERRQ(ierr);
329     for( clid_iterator = 0 ; clid_iterator < nselected_1 ; clid_iterator++ ){
330       PetscInt flid = selected_idx_1[clid_iterator]; assert(flid != -1);
331       PetscScalar AA[3][3];
332       PetscBLASInt N=3,NRHS=1,LDA=3,IPIV[3],LDB=3,INFO;
333       do{
334         if( flid < nFineLoc ) {  /* could be a ghost */
335           PetscInt bestTID = -1; PetscReal best_alpha = 1.e10;
336           const PetscInt fgid = flid + myFine0;
337           /* compute shape function for gid */
338           const PetscReal fcoord[3] = { coords[flid], coords[nnodes + flid], 1.0 };
339           PetscBool haveit = PETSC_FALSE; PetscScalar alpha[3]; PetscInt clids[3];
340           /* look for it */
341           for( tid = node_tri[clid_iterator], jj=0;
342                jj < 5 && !haveit && tid != -1;
343                jj++ ){
344             for(tt=0;tt<3;tt++){
345               PetscInt cid2 = mid.trianglelist[3*tid + tt];
346               PetscInt lid2 = selected_idx_2[cid2];
347               AA[tt][0] = coords[lid2]; AA[tt][1] = coords[nnodes + lid2]; AA[tt][2] = 1.0;
348               clids[tt] = cid2; /* store for interp */
349             }
350 
351             for(tt=0;tt<3;tt++) alpha[tt] = (PetscScalar)fcoord[tt];
352 
353             /* SUBROUTINE DGESV( N, NRHS, A, LDA, IPIV, B, LDB, INFO ) */
354             LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO);
355             {
356               PetscBool have=PETSC_TRUE;  PetscReal lowest=1.e10;
357               for( tt = 0, idx = 0 ; tt < 3 ; tt++ ) {
358                 if( PetscRealPart(alpha[tt]) > (1.0+EPS) || PetscRealPart(alpha[tt]) < -EPS ) have = PETSC_FALSE;
359                 if( PetscRealPart(alpha[tt]) < lowest ){
360                   lowest = PetscRealPart(alpha[tt]);
361                   idx = tt;
362                 }
363               }
364               haveit = have;
365             }
366             tid = mid.neighborlist[3*tid + idx];
367           }
368 
369           if( !haveit ) {
370             /* brute force */
371             for(tid=0 ; tid<mid.numberoftriangles && !haveit ; tid++ ){
372               for(tt=0;tt<3;tt++){
373                 PetscInt cid2 = mid.trianglelist[3*tid + tt];
374                 PetscInt lid2 = selected_idx_2[cid2];
375                 AA[tt][0] = coords[lid2]; AA[tt][1] = coords[nnodes + 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               LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO);
381               {
382                 PetscBool have=PETSC_TRUE;  PetscReal worst=0.0, v;
383                 for(tt=0; tt<3 && have ;tt++) {
384                   if( PetscRealPart(alpha[tt]) > 1.0+EPS || PetscRealPart(alpha[tt]) < -EPS ) have=PETSC_FALSE;
385                   if( (v=PetscAbs(PetscRealPart(alpha[tt])-0.5)) > worst ) worst = v;
386                 }
387                 if( worst < best_alpha ) {
388                   best_alpha = worst; bestTID = tid;
389                 }
390                 haveit = have;
391               }
392             }
393           }
394           if( !haveit ) {
395             if( best_alpha > *a_worst_best ) *a_worst_best = best_alpha;
396             /* use best one */
397             for(tt=0;tt<3;tt++){
398               PetscInt cid2 = mid.trianglelist[3*bestTID + tt];
399               PetscInt lid2 = selected_idx_2[cid2];
400               AA[tt][0] = coords[lid2]; AA[tt][1] = coords[nnodes + lid2]; AA[tt][2] = 1.0;
401               clids[tt] = cid2; /* store for interp */
402             }
403             for(tt=0;tt<3;tt++) alpha[tt] = fcoord[tt];
404             /* SUBROUTINE DGESV( N, NRHS, A, LDA, IPIV, B, LDB, INFO ) */
405             LAPACKgesv_(&N, &NRHS, (PetscScalar*)AA, &LDA, IPIV, alpha, &LDB, &INFO);
406           }
407 
408           /* put in row of P */
409           for(idx=0;idx<3;idx++){
410             PetscScalar shp = alpha[idx];
411             if( PetscAbs(PetscRealPart(shp)) > 1.e-6 ) {
412               PetscInt cgid = crsGID[clids[idx]];
413               PetscInt jj = cgid*bs, ii = fgid*bs; /* need to gloalize */
414               for(tt=0 ; tt < bs ; tt++, ii++, jj++ ){
415                 ierr = MatSetValues(a_Prol,1,&ii,1,&jj,&shp,INSERT_VALUES); CHKERRQ(ierr);
416               }
417             }
418           }
419         } /* local vertex test */
420       } while( (flid=llist_idx[flid]) != -1 );
421     }
422     ierr = ISRestoreIndices( selected_2, &selected_idx_2 );     CHKERRQ(ierr);
423     ierr = ISRestoreIndices( selected_1, &selected_idx_1 );     CHKERRQ(ierr);
424     ierr = ISRestoreIndices( locals_llist, &llist_idx );     CHKERRQ(ierr);
425     ierr = MatAssemblyBegin(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
426     ierr = MatAssemblyEnd(a_Prol,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
427 
428     ierr = PetscFree( node_tri );  CHKERRQ(ierr);
429     ierr = PetscFree( nTri );  CHKERRQ(ierr);
430   }
431 #if defined PETSC_USE_LOG
432   ierr = PetscLogEventEnd(gamg_setup_events[FIND_V],0,0,0,0);CHKERRQ(ierr);
433 #endif
434   free( mid.trianglelist );
435   free( mid.neighborlist );
436   ierr = PetscFree( in.pointlist );  CHKERRQ(ierr);
437 
438   PetscFunctionReturn(0);
439 #else
440     SETERRQ(((PetscObject)a_Prol)->comm,PETSC_ERR_LIB,"configure with TRIANGLE to use geometric MG");
441 #endif
442 }
443 /* -------------------------------------------------------------------------- */
444 /*
445    getGIDsOnSquareGraph - square graph, get
446 
447    Input Parameter:
448    . selected_1 - selected local indices (includes ghosts in input Gmat_1)
449    . Gmat1 - graph that goes with 'selected_1'
450    Output Parameter:
451    . a_selected_2 - selected local indices (includes ghosts in output a_Gmat_2)
452    . a_Gmat_2 - graph that is squared of 'Gmat_1'
453    . a_crsGID[a_selected_2.size()] - map of global IDs of coarse grid nodes
454 */
455 #undef __FUNCT__
456 #define __FUNCT__ "getGIDsOnSquareGraph"
457 PetscErrorCode getGIDsOnSquareGraph( const IS selected_1,
458                                      const Mat Gmat1,
459                                      IS *a_selected_2,
460                                      Mat *a_Gmat_2,
461                                      PetscInt **a_crsGID
462                                      )
463 {
464   PetscErrorCode ierr;
465   PetscMPIInt    mype,npe;
466   PetscInt       *crsGID, kk,my0,Iend,nloc,nSelected_1;
467   const PetscInt *selected_idx;
468   MPI_Comm       wcomm = ((PetscObject)Gmat1)->comm;
469 
470   PetscFunctionBegin;
471   ierr = MPI_Comm_rank(wcomm,&mype);CHKERRQ(ierr);
472   ierr = MPI_Comm_size(wcomm,&npe);CHKERRQ(ierr);
473   ierr = MatGetOwnershipRange(Gmat1,&my0,&Iend); CHKERRQ(ierr); /* AIJ */
474   nloc = Iend - my0; /* this does not change */
475   ierr = ISGetLocalSize( selected_1, &nSelected_1 );        CHKERRQ(ierr);
476 
477   if (npe == 1) { /* not much to do in serial */
478     ierr = PetscMalloc( nSelected_1*sizeof(PetscInt), &crsGID ); CHKERRQ(ierr);
479     for(kk=0;kk<nSelected_1;kk++) crsGID[kk] = kk;
480     *a_Gmat_2 = 0;
481     *a_selected_2 = selected_1; /* needed? */
482   }
483   else {
484     PetscInt      idx,num_fine_ghosts,num_crs_ghost,nLocalSelected,myCrs0;
485     Mat_MPIAIJ   *mpimat2;
486     Mat           Gmat2;
487     Vec           locState;
488     PetscScalar   *cpcol_state;
489 
490     /* get 'nLocalSelected' */
491     ierr = ISGetIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
492     for(kk=0,nLocalSelected=0;kk<nSelected_1;kk++){
493       PetscInt lid = selected_idx[kk];
494       if(lid<nloc) nLocalSelected++;
495     }
496     ierr = ISRestoreIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
497     /* scan my coarse zero gid, set 'lid_state' with coarse GID */
498     MPI_Scan( &nLocalSelected, &myCrs0, 1, MPIU_INT, MPIU_SUM, wcomm );
499     myCrs0 -= nLocalSelected;
500 
501     if( a_Gmat_2 != 0 ) { /* output */
502       /* grow graph to get wider set of selected vertices to cover fine grid, invalidates 'llist' */
503       ierr = MatTransposeMatMult(Gmat1, Gmat1, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &Gmat2 );   CHKERRQ(ierr);
504       *a_Gmat_2 = Gmat2; /* output */
505     }
506     else Gmat2 = Gmat1;  /* use local to get crsGIDs at least */
507     /* get coarse grid GIDS for selected (locals and ghosts) */
508     mpimat2 = (Mat_MPIAIJ*)Gmat2->data;
509     ierr = MatGetVecs( Gmat2, &locState, 0 );         CHKERRQ(ierr);
510     ierr = VecSet( locState, (PetscScalar)(PetscReal)(-1) );  CHKERRQ(ierr); /* set with UNKNOWN state */
511     ierr = ISGetIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
512     for(kk=0;kk<nLocalSelected;kk++){
513       PetscInt fgid = selected_idx[kk] + my0;
514       PetscScalar v = (PetscScalar)(kk+myCrs0);
515       ierr = VecSetValues( locState, 1, &fgid, &v, INSERT_VALUES );  CHKERRQ(ierr); /* set with PID */
516     }
517     ierr = ISRestoreIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
518     ierr = VecAssemblyBegin( locState ); CHKERRQ(ierr);
519     ierr = VecAssemblyEnd( locState ); CHKERRQ(ierr);
520     ierr = VecScatterBegin(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
521     ierr =   VecScatterEnd(mpimat2->Mvctx,locState,mpimat2->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
522     ierr = VecGetLocalSize( mpimat2->lvec, &num_fine_ghosts ); CHKERRQ(ierr);
523     ierr = VecGetArray( mpimat2->lvec, &cpcol_state ); CHKERRQ(ierr);
524     for(kk=0,num_crs_ghost=0;kk<num_fine_ghosts;kk++){
525       if( (PetscInt)PetscRealPart(cpcol_state[kk]) != -1 ) num_crs_ghost++;
526     }
527     ierr = PetscMalloc( (nLocalSelected+num_crs_ghost)*sizeof(PetscInt), &crsGID ); CHKERRQ(ierr); /* output */
528     {
529       PetscInt *selected_set;
530       ierr = PetscMalloc( (nLocalSelected+num_crs_ghost)*sizeof(PetscInt), &selected_set ); CHKERRQ(ierr);
531       /* do ghost of 'crsGID' */
532       for(kk=0,idx=nLocalSelected;kk<num_fine_ghosts;kk++){
533         if( (PetscInt)PetscRealPart(cpcol_state[kk]) != -1 ){
534           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
535           selected_set[idx] = nloc + kk;
536           crsGID[idx++] = cgid;
537         }
538       }
539       assert(idx==(nLocalSelected+num_crs_ghost));
540       ierr = VecRestoreArray( mpimat2->lvec, &cpcol_state ); CHKERRQ(ierr);
541       /* do locals in 'crsGID' */
542       ierr = VecGetArray( locState, &cpcol_state ); CHKERRQ(ierr);
543       for(kk=0,idx=0;kk<nloc;kk++){
544         if( (PetscInt)PetscRealPart(cpcol_state[kk]) != -1 ){
545           PetscInt cgid = (PetscInt)PetscRealPart(cpcol_state[kk]);
546           selected_set[idx] = kk;
547           crsGID[idx++] = cgid;
548         }
549       }
550       assert(idx==nLocalSelected);
551       ierr = VecRestoreArray( locState, &cpcol_state ); CHKERRQ(ierr);
552 
553       if( a_selected_2 != 0 ) { /* output */
554         ierr = ISCreateGeneral(PETSC_COMM_SELF,(nLocalSelected+num_crs_ghost),selected_set,PETSC_COPY_VALUES,a_selected_2);
555         CHKERRQ(ierr);
556       }
557       ierr = PetscFree( selected_set );  CHKERRQ(ierr);
558     }
559     ierr = VecDestroy( &locState );                    CHKERRQ(ierr);
560   }
561   *a_crsGID = crsGID; /* output */
562 
563   PetscFunctionReturn(0);
564 }
565 
566 /* -------------------------------------------------------------------------- */
567 /*
568    PCGAMGgraph_GEO
569 
570   Input Parameter:
571    . pc - this
572    . Amat - matrix on this fine level
573   Output Parameter:
574    . a_Gmat
575 */
576 #undef __FUNCT__
577 #define __FUNCT__ "PCGAMGgraph_GEO"
578 PetscErrorCode PCGAMGgraph_GEO( PC pc,
579                                 const Mat Amat,
580                                 Mat *a_Gmat
581                                 )
582 {
583   PetscErrorCode ierr;
584   PC_MG          *mg = (PC_MG*)pc->data;
585   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
586   const PetscInt verbose = pc_gamg->verbose;
587   const PetscReal vfilter = pc_gamg->threshold;
588   PetscMPIInt    mype,npe;
589   MPI_Comm       wcomm = ((PetscObject)Amat)->comm;
590   Mat            Gmat;
591 
592   PetscFunctionBegin;
593   ierr = MPI_Comm_rank( wcomm, &mype);  CHKERRQ(ierr);
594   ierr = MPI_Comm_size( wcomm, &npe);   CHKERRQ(ierr);
595 
596   ierr  = createSimpleGraph( Amat, &Gmat ); CHKERRQ( ierr );
597   ierr  = scaleFilterGraph( &Gmat, vfilter, PETSC_TRUE, verbose ); CHKERRQ( ierr );
598 
599   *a_Gmat = Gmat;
600 
601   PetscFunctionReturn(0);
602 }
603 
604 /* -------------------------------------------------------------------------- */
605 /*
606    PCGAMGcoarsen_GEO
607 
608   Input Parameter:
609    . pc - this
610    . Gmat - graph
611   Output Parameter:
612    . a_selected - selected indices (local)
613    . a_llist_parent - linked list from selected indices for data locality only
614 */
615 #undef __FUNCT__
616 #define __FUNCT__ "PCGAMGcoarsen_GEO"
617 PetscErrorCode PCGAMGcoarsen_GEO( PC pc,
618                                   const Mat Gmat,
619                                   IS *a_selected,
620                                   IS *a_llist_parent
621                                   )
622 {
623   PetscErrorCode ierr;
624   PC_MG          *mg = (PC_MG*)pc->data;
625   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
626   PetscInt       Istart,Iend,nloc,kk,Ii,ncols;
627   PetscMPIInt    mype,npe;
628   IS perm,selected,llist_parent;
629   GAMGNode *gnodes;
630   PetscInt *permute;
631   MPI_Comm  wcomm = ((PetscObject)Gmat)->comm;
632 
633   PetscFunctionBegin;
634   ierr = MPI_Comm_rank( wcomm, &mype);  CHKERRQ(ierr);
635   ierr = MPI_Comm_size( wcomm, &npe);   CHKERRQ(ierr);
636   ierr = MatGetOwnershipRange( Gmat, &Istart, &Iend ); CHKERRQ(ierr);
637   nloc = (Iend-Istart);
638 
639   /* create random permutation with sort for geo-mg */
640   ierr = PetscMalloc( nloc*sizeof(GAMGNode), &gnodes ); CHKERRQ(ierr);
641   ierr = PetscMalloc( nloc*sizeof(PetscInt), &permute ); CHKERRQ(ierr);
642 
643   for (Ii=Istart; Ii<Iend; Ii++) { /* locals only? */
644     ierr = MatGetRow(Gmat,Ii,&ncols,0,0); CHKERRQ(ierr);
645     {
646       PetscInt lid = Ii - Istart;
647       gnodes[lid].lid = lid;
648       gnodes[lid].degree = ncols;
649     }
650     ierr = MatRestoreRow(Gmat,Ii,&ncols,0,0); CHKERRQ(ierr);
651   }
652   /* randomize */
653   srand(1); /* make deterministic */
654   if( PETSC_TRUE ) {
655     PetscBool *bIndexSet;
656     ierr = PetscMalloc( nloc*sizeof(PetscBool), &bIndexSet ); CHKERRQ(ierr);
657     for ( Ii = 0; Ii < nloc ; Ii++) bIndexSet[Ii] = PETSC_FALSE;
658     for ( Ii = 0; Ii < nloc ; Ii++)
659     {
660       PetscInt iSwapIndex = rand()%nloc;
661       if (!bIndexSet[iSwapIndex] && iSwapIndex != Ii)
662       {
663         GAMGNode iTemp = gnodes[iSwapIndex];
664         gnodes[iSwapIndex] = gnodes[Ii];
665         gnodes[Ii] = iTemp;
666         bIndexSet[Ii] = PETSC_TRUE;
667         bIndexSet[iSwapIndex] = PETSC_TRUE;
668       }
669     }
670     ierr = PetscFree( bIndexSet );  CHKERRQ(ierr);
671   }
672   /* only sort locals */
673   qsort( gnodes, nloc, sizeof(GAMGNode), compare );
674   /* create IS of permutation */
675   for(kk=0;kk<nloc;kk++) { /* locals only */
676     permute[kk] = gnodes[kk].lid;
677   }
678   ierr = ISCreateGeneral(PETSC_COMM_SELF, nloc, permute, PETSC_COPY_VALUES, &perm);
679   CHKERRQ(ierr);
680 
681   ierr = PetscFree( gnodes );  CHKERRQ(ierr);
682   ierr = PetscFree( permute );  CHKERRQ(ierr);
683 
684   /* get MIS aggs */
685   ierr = maxIndSetAgg( perm, Gmat, PETSC_FALSE, pc_gamg->verbose, &selected, &llist_parent ); CHKERRQ(ierr);
686 
687   ierr = ISDestroy( &perm );                    CHKERRQ(ierr);
688 
689   *a_selected = selected;
690   *a_llist_parent = llist_parent;
691 
692   PetscFunctionReturn(0);
693 }
694 
695 /* -------------------------------------------------------------------------- */
696 /*
697  PCGAMGprolongator_GEO
698 
699  Input Parameter:
700  . pc - this
701  . Amat - matrix on this fine level
702  . Graph - used to get ghost data for nodes in
703  . selected - [nselected inc. chosts]
704  . llist_1 - [nloc + Gmat.nghost] linked list
705  Output Parameter:
706  . a_P_out - prolongation operator to the next level
707  */
708 #undef __FUNCT__
709 #define __FUNCT__ "PCGAMGprolongator_GEO"
710 PetscErrorCode PCGAMGprolongator_GEO( PC pc,
711                                       const Mat Amat,
712                                       const Mat Gmat,
713                                       IS selected_1,
714                                       IS llist_1,
715                                       Mat *a_P_out
716                                       )
717 {
718   PC_MG          *mg = (PC_MG*)pc->data;
719   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
720   const PetscInt  verbose = pc_gamg->verbose;
721   const PetscInt  dim = pc_gamg->data_cell_cols, data_cols = pc_gamg->data_cell_cols;
722   PetscErrorCode ierr;
723   PetscInt       Istart,Iend,nloc,jj,kk,nLocalSelected,bs;
724   Mat            Prol;
725   PetscMPIInt    mype, npe;
726   MPI_Comm       wcomm = ((PetscObject)Amat)->comm;
727   IS             selected_2;
728   const PetscInt *selected_idx;
729 
730   PetscFunctionBegin;
731   ierr = MPI_Comm_rank(wcomm,&mype);CHKERRQ(ierr);
732   ierr = MPI_Comm_size(wcomm,&npe);CHKERRQ(ierr);
733   ierr = MatGetOwnershipRange( Amat, &Istart, &Iend ); CHKERRQ(ierr);
734   ierr  = MatGetBlockSize( Amat, &bs );               CHKERRQ( ierr );
735   nloc = (Iend-Istart)/bs; assert((Iend-Istart)%bs==0);
736 
737   /* get 'nLocalSelected' */
738   ierr = ISGetLocalSize( selected_1, &jj );        CHKERRQ(ierr);
739   ierr = ISGetIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
740   for(kk=0,nLocalSelected=0;kk<jj;kk++) {
741     PetscInt lid = selected_idx[kk];
742     if(lid<nloc) nLocalSelected++;
743   }
744   ierr = ISRestoreIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
745 
746   /* create prolongator, create P matrix */
747   ierr = MatCreateMPIAIJ(wcomm,
748                          nloc*bs, nLocalSelected*bs,
749                          PETSC_DETERMINE, PETSC_DETERMINE,
750                          3*data_cols, PETSC_NULL, /* don't have a good way to set this!!! */
751                          3*data_cols, PETSC_NULL,
752                          &Prol );
753   CHKERRQ(ierr);
754 
755   /* can get all points "removed" - but not on geomg */
756   ierr =  MatGetSize( Prol, &kk, &jj ); CHKERRQ(ierr);
757   if( jj==0 ) {
758     if( verbose ) {
759       PetscPrintf(PETSC_COMM_WORLD,"[%d]%s ERROE: no selected points on coarse grid\n",mype,__FUNCT__);
760     }
761     ierr = MatDestroy( &Prol );  CHKERRQ(ierr);
762     *a_P_out = PETSC_NULL;  /* out */
763     PetscFunctionReturn(0);
764   }
765 
766   {
767     PetscReal *coords;
768     PetscInt nnodes;
769     PetscInt  *crsGID;
770     Mat        Gmat2;
771 
772     assert(dim==data_cols);
773     /* grow ghost data for better coarse grid cover of fine grid */
774 #if defined PETSC_USE_LOG
775     ierr = PetscLogEventBegin(gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
776 #endif
777     ierr = getGIDsOnSquareGraph( selected_1, Gmat, &selected_2, &Gmat2, &crsGID );
778     CHKERRQ(ierr);
779     /* llist is now not valid wrt squared graph, but will work as iterator in 'triangulateAndFormProl' */
780 #if defined PETSC_USE_LOG
781     ierr = PetscLogEventEnd(gamg_setup_events[SET5],0,0,0,0);CHKERRQ(ierr);
782 #endif
783     /* create global vector of coorindates in 'coords' */
784     if (npe > 1) {
785       ierr = getDataWithGhosts( Gmat2, dim, pc_gamg->data, &nnodes, &coords );
786       CHKERRQ(ierr);
787     }
788     else {
789       coords = (PetscReal*)pc_gamg->data;
790       nnodes = nloc;
791     }
792     ierr = MatDestroy( &Gmat2 );  CHKERRQ(ierr);
793 
794     /* triangulate */
795     if( dim == 2 ) {
796       PetscReal metric,tm;
797 #if defined PETSC_USE_LOG
798       ierr = PetscLogEventBegin(gamg_setup_events[SET6],0,0,0,0);CHKERRQ(ierr);
799 #endif
800       ierr = triangulateAndFormProl( selected_2, nnodes, coords,
801                                      selected_1, llist_1, crsGID, bs, Prol, &metric );
802       CHKERRQ(ierr);
803 #if defined PETSC_USE_LOG
804       ierr = PetscLogEventEnd(gamg_setup_events[SET6],0,0,0,0); CHKERRQ(ierr);
805 #endif
806       ierr = PetscFree( crsGID );  CHKERRQ(ierr);
807 
808       /* clean up and create coordinates for coarse grid (output) */
809       if (npe > 1) ierr = PetscFree( coords ); CHKERRQ(ierr);
810 
811       ierr = MPI_Allreduce( &metric, &tm, 1, MPIU_REAL, MPIU_MAX, wcomm );  CHKERRQ(ierr);
812       if( tm > 1. ) { /* needs to be globalized - should not happen */
813         if( verbose ) {
814           PetscPrintf(PETSC_COMM_WORLD,"[%d]%s failed metric for coarse grid %e\n",mype,__FUNCT__,tm);
815         }
816         ierr = MatDestroy( &Prol );  CHKERRQ(ierr);
817         Prol = PETSC_NULL;
818       }
819       else if( metric > .0 ) {
820         if( verbose ) {
821           PetscPrintf(PETSC_COMM_WORLD,"[%d]%s worst metric for coarse grid = %e\n",mype,__FUNCT__,metric);
822         }
823       }
824     } else {
825       SETERRQ(wcomm,PETSC_ERR_LIB,"3D not implemented for 'geo' AMG");
826     }
827     { /* create next coords - output */
828       PetscReal *crs_crds;
829       ierr = PetscMalloc( dim*nLocalSelected*sizeof(PetscReal), &crs_crds );
830       CHKERRQ(ierr);
831       ierr = ISGetIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
832       for(kk=0;kk<nLocalSelected;kk++){/* grab local select nodes to promote - output */
833         PetscInt lid = selected_idx[kk];
834         for(jj=0;jj<dim;jj++) crs_crds[jj*nLocalSelected + kk] = pc_gamg->data[jj*nloc + lid];
835       }
836       ierr = ISRestoreIndices( selected_1, &selected_idx );     CHKERRQ(ierr);
837 
838       ierr = PetscFree( pc_gamg->data ); CHKERRQ( ierr );
839       pc_gamg->data = crs_crds; /* out */
840       pc_gamg->data_sz = dim*nLocalSelected;
841     }
842     if (npe > 1) {
843       ierr = ISDestroy( &selected_2 ); CHKERRQ(ierr); /* this is selected_1 in serial */
844     }
845   }
846   *a_P_out = Prol;  /* out */
847 
848   PetscFunctionReturn(0);
849 }
850 
851 /* -------------------------------------------------------------------------- */
852 /*
853  PCCreateGAMG_GEO
854 
855   Input Parameter:
856    . pc -
857 */
858 #undef __FUNCT__
859 #define __FUNCT__ "PCCreateGAMG_GEO"
860 PetscErrorCode  PCCreateGAMG_GEO( PC pc )
861 {
862   PetscErrorCode  ierr;
863   PC_MG           *mg = (PC_MG*)pc->data;
864   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
865 
866   PetscFunctionBegin;
867   pc->ops->setfromoptions = PCSetFromOptions_GEO;
868   /* pc->ops->destroy        = PCDestroy_GEO; */
869   /* reset does not do anything; setup not virtual */
870 
871   /* set internal function pointers */
872   pc_gamg->graph = PCGAMGgraph_GEO;
873   pc_gamg->coarsen = PCGAMGcoarsen_GEO;
874   pc_gamg->prolongator = PCGAMGprolongator_GEO;
875   pc_gamg->optprol = 0;
876 
877   pc_gamg->createdefaultdata = PCSetData_GEO;
878 
879   ierr = PetscObjectComposeFunctionDynamic( (PetscObject)pc,
880                                             "PCSetCoordinates_C",
881                                             "PCSetCoordinates_GEO",
882                                             PCSetCoordinates_GEO);CHKERRQ(ierr);
883 
884   PetscFunctionReturn(0);
885 }
886