Actual source code: ex6.c

  2: static char help[] = "Demonstrates using 3 DA's to manage a slightly non-trivial grid";

 4:  #include petscda.h
 5:  #include petscsys.h

  7: struct _p_FA {
  8:   MPI_Comm   comm[3];
  9:   PetscInt   xl[3],yl[3],ml[3],nl[3];    /* corners and sizes of local vector in DA */
 10:   PetscInt   xg[3],yg[3],mg[3],ng[3];    /* corners and sizes of global vector in DA */
 11:   PetscInt   offl[3],offg[3];            /* offset in local and global vector of region 1, 2 and 3 portions */
 12:   Vec        g,l;
 13:   VecScatter vscat;
 14:   PetscInt   p1,p2,r1,r2,r1g,r2g,sw;
 15: };
 16: typedef struct _p_FA *FA;

 18: typedef struct {
 19:   PetscScalar X;
 20:   PetscScalar Y;
 21: } Field;

 23: PetscErrorCode FAGetLocalCorners(FA fa,PetscInt j,PetscInt *x,PetscInt *y,PetscInt *m,PetscInt *n)
 24: {
 26:   if (fa->comm[j]) {
 27:     *x = fa->xl[j];
 28:     *y = fa->yl[j];
 29:     *m = fa->ml[j];
 30:     *n = fa->nl[j];
 31:   } else {
 32:     *x = *y = *m = *n = 0;
 33:   }
 34:   return(0);
 35: }

 37: PetscErrorCode FAGetGlobalCorners(FA fa,PetscInt j,PetscInt *x,PetscInt *y,PetscInt *m,PetscInt *n)
 38: {
 40:   if (fa->comm[j]) {
 41:     *x = fa->xg[j];
 42:     *y = fa->yg[j];
 43:     *m = fa->mg[j];
 44:     *n = fa->ng[j];
 45:   } else {
 46:     *x = *y = *m = *n = 0;
 47:   }
 48:   return(0);
 49: }

 51: PetscErrorCode FAGetLocalArray(FA fa,Vec v,PetscInt j,Field ***f)
 52: {
 54:   PetscScalar    *va;
 55:   PetscInt       i;
 56:   Field          **a;

 59:   if (fa->comm[j]) {
 60:     VecGetArray(v,&va);
 61:     PetscMalloc(fa->nl[j]*sizeof(Field*),&a);
 62:     for (i=0; i<fa->nl[j]; i++) (a)[i] = (Field*) (va + 2*fa->offl[j] + i*2*fa->ml[j] - 2*fa->xl[j]);
 63:     *f = a - fa->yl[j];
 64:     VecRestoreArray(v,&va);
 65:   } else {
 66:     *f = 0;
 67:   }
 68:   return(0);
 69: }

 71: PetscErrorCode FARestoreLocalArray(FA fa,Vec v,PetscInt j,Field ***f)
 72: {
 74:   void           *dummy;

 77:   if (fa->comm[j]) {
 78:     dummy = *f + fa->yl[j];
 79:     PetscFree(dummy);
 80:   }
 81:   return(0);
 82: }

 84: PetscErrorCode FAGetGlobalArray(FA fa,Vec v,PetscInt j,Field ***f)
 85: {
 87:   PetscScalar    *va;
 88:   PetscInt       i;
 89:   Field          **a;

 92:   if (fa->comm[j]) {
 93:     VecGetArray(v,&va);
 94:     PetscMalloc(fa->ng[j]*sizeof(Field*),&a);
 95:     for (i=0; i<fa->ng[j]; i++) (a)[i] = (Field*) (va + 2*fa->offg[j] + i*2*fa->mg[j] - 2*fa->xg[j]);
 96:     *f = a - fa->yg[j];
 97:     VecRestoreArray(v,&va);
 98:   } else {
 99:     *f = 0;
100:   }
101:   return(0);
102: }

104: PetscErrorCode FARestoreGlobalArray(FA fa,Vec v,PetscInt j,Field ***f)
105: {
107:   void           *dummy;

110:   if (fa->comm[j]) {
111:     dummy = *f + fa->yg[j];
112:     PetscFree(dummy);
113:   }
114:   return(0);
115: }

117: PetscErrorCode FAGetGlobalVector(FA fa,Vec *v)
118: {
121:   VecDuplicate(fa->g,v);
122:   return(0);
123: }

125: PetscErrorCode FAGetLocalVector(FA fa,Vec *v)
126: {
129:   VecDuplicate(fa->l,v);
130:   return(0);
131: }

133: PetscErrorCode FAGlobalToLocal(FA fa,Vec g,Vec l)
134: {
137:   VecScatterBegin(g,l,INSERT_VALUES,SCATTER_FORWARD,fa->vscat);
138:   VecScatterEnd(g,l,INSERT_VALUES,SCATTER_FORWARD,fa->vscat);
139:   return(0);
140: }

142: PetscErrorCode FADestroy(FA fa)
143: {
146:   VecDestroy(fa->g);
147:   VecDestroy(fa->l);
148:   VecScatterDestroy(fa->vscat);
149:   PetscFree(fa);
150:   return(0);
151: }

153: PetscErrorCode FACreate(FA *infa)
154: {
155:   FA             fa;
156:   PetscMPIInt    rank;
157:   PetscInt       tonglobal,globalrstart,x,nx,y,ny,*tonatural,i,j,*to,*from,offt[3];
158:   PetscInt       *fromnatural,fromnglobal,nscat,nlocal,cntl1,cntl2,cntl3,*indices;

161:   /* Each DA manages the local vector for the portion of region 1, 2, and 3 for that processor
162:      Each DA can belong on any subset (overlapping between DA's or not) of processors
163:      For processes that a particular DA does not exist on, the corresponding comm should be set to zero
164:   */
165:   DA             da1 = 0,da2 = 0,da3 = 0;
166:   /* 
167:       v1, v2, v3 represent the local vector for a single DA
168:   */
169:   Vec            vl1 = 0,vl2 = 0,vl3 = 0, vg1 = 0, vg2 = 0,vg3 = 0;

171:   /*
172:      globalvec and friends represent the global vectors that are used for the PETSc solvers 
173:      localvec represents the concatenation of the (up to) 3 local vectors; vl1, vl2, vl3

175:      tovec and friends represent intermediate vectors that are ONLY used for setting up the 
176:      final communication patterns. Once this setup routine is complete they are destroyed.
177:      The tovec  is like the globalvec EXCEPT it has redundant locations for the ghost points
178:      between regions 2+3 and 1.
179:   */
180:   AO             toao,globalao;
181:   IS             tois,globalis,is;
182:   Vec            tovec,globalvec,localvec;
183:   VecScatter     vscat;
184:   PetscScalar    *globalarray,*localarray,*toarray;

186:   PetscNew(struct _p_FA,&fa);
187:   /*
188:       fa->sw is the stencil width  

190:       fa->p1 is the width of region 1, fa->p2 the width of region 2 (must be the same)
191:       fa->r1 height of region 1 
192:       fa->r2 height of region 2
193:  
194:       fa->r2 is also the height of region 3-4
195:       (fa->p1 - fa->p2)/2 is the width of both region 3 and region 4
196:   */
197:   fa->p1 = 24;
198:   fa->p2 = 15;
199:   fa->r1 = 6;
200:   fa->r2 = 6;
201:   fa->sw = 1;
202:   fa->r1g = fa->r1 + fa->sw;
203:   fa->r2g = fa->r2 + fa->sw;

205:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

207:   fa->comm[0] = PETSC_COMM_WORLD;
208:   fa->comm[1] = PETSC_COMM_WORLD;
209:   fa->comm[2] = PETSC_COMM_WORLD;
210:   /* Test case with different communicators */
211:   /* Normally one would use MPI_Comm routines to build MPI communicators on which you wish to partition the DAs*/
212:   /*
213:   if (rank == 0) {
214:     fa->comm[0] = PETSC_COMM_SELF;
215:     fa->comm[1] = 0;
216:     fa->comm[2] = 0;
217:   } else if (rank == 1) {
218:     fa->comm[0] = 0;  
219:     fa->comm[1] = PETSC_COMM_SELF;
220:     fa->comm[2] = 0;  
221:   } else {
222:     fa->comm[0] = 0;  
223:     fa->comm[1] = 0;
224:     fa->comm[2] = PETSC_COMM_SELF;
225:   } */

227:   if (fa->p2 > fa->p1 - 3)   SETERRQ(1,"Width of region fa->p2 must be at least 3 less then width of region 1");
228:   if (!((fa->p2 - fa->p1) % 2)) SETERRQ(1,"width of region 3 must NOT be divisible by 2");

230:   if (fa->comm[1]) {
231:     DACreate2d(fa->comm[1],DA_XPERIODIC,DA_STENCIL_BOX,fa->p2,fa->r2g,PETSC_DECIDE,PETSC_DECIDE,1,fa->sw,PETSC_NULL,PETSC_NULL,&da2);
232:     DAGetLocalVector(da2,&vl2);
233:     DAGetGlobalVector(da2,&vg2);
234:   }
235:   if (fa->comm[2]) {
236:     DACreate2d(fa->comm[2],DA_NONPERIODIC,DA_STENCIL_BOX,fa->p1-fa->p2,fa->r2g,PETSC_DECIDE,PETSC_DECIDE,1,fa->sw,PETSC_NULL,PETSC_NULL,&da3);
237:     DAGetLocalVector(da3,&vl3);
238:     DAGetGlobalVector(da3,&vg3);
239:   }
240:   if (fa->comm[0]) {
241:     DACreate2d(fa->comm[0],DA_NONPERIODIC,DA_STENCIL_BOX,fa->p1,fa->r1g,PETSC_DECIDE,PETSC_DECIDE,1,fa->sw,PETSC_NULL,PETSC_NULL,&da1);
242:     DAGetLocalVector(da1,&vl1);
243:     DAGetGlobalVector(da1,&vg1);
244:   }

246:   /* count the number of unknowns owned on each processor and determine the starting point of each processors ownership 
247:      for global vector with redundancy */
248:   tonglobal = 0;
249:   if (fa->comm[1]) {
250:     DAGetCorners(da2,&x,&y,0,&nx,&ny,0);
251:     tonglobal += nx*ny;
252:   }
253:   if (fa->comm[2]) {
254:     DAGetCorners(da3,&x,&y,0,&nx,&ny,0);
255:     tonglobal += nx*ny;
256:   }
257:   if (fa->comm[0]) {
258:     DAGetCorners(da1,&x,&y,0,&nx,&ny,0);
259:     tonglobal += nx*ny;
260:   }
261:   PetscSynchronizedPrintf(PETSC_COMM_WORLD,"[%d] Number of unknowns owned %d\n",rank,tonglobal);
262:   PetscSynchronizedFlush(PETSC_COMM_WORLD);
263: 
264:   /* Get tonatural number for each node */
265:   PetscMalloc((tonglobal+1)*sizeof(PetscInt),&tonatural);
266:   tonglobal = 0;
267:   if (fa->comm[1]) {
268:     DAGetCorners(da2,&x,&y,0,&nx,&ny,0);
269:     for (j=0; j<ny; j++) {
270:       for (i=0; i<nx; i++) {
271:         tonatural[tonglobal++] = (fa->p1 - fa->p2)/2 + x + i + fa->p1*(y + j);
272:       }
273:     }
274:   }
275:   if (fa->comm[2]) {
276:     DAGetCorners(da3,&x,&y,0,&nx,&ny,0);
277:     for (j=0; j<ny; j++) {
278:       for (i=0; i<nx; i++) {
279:         if (x + i < (fa->p1 - fa->p2)/2) tonatural[tonglobal++] = x + i + fa->p1*(y + j);
280:         else tonatural[tonglobal++] = fa->p2 + x + i + fa->p1*(y + j);
281:       }
282:     }
283:   }
284:   if (fa->comm[0]) {
285:     DAGetCorners(da1,&x,&y,0,&nx,&ny,0);
286:     for (j=0; j<ny; j++) {
287:       for (i=0; i<nx; i++) {
288:         tonatural[tonglobal++] = fa->p1*fa->r2g + x + i + fa->p1*(y + j);
289:       }
290:     }
291:   }
292:   /*  PetscIntView(tonglobal,tonatural,PETSC_VIEWER_STDOUT_WORLD); */
293:   AOCreateBasic(PETSC_COMM_WORLD,tonglobal,tonatural,0,&toao);
294:   PetscFree(tonatural);

296:   /* count the number of unknowns owned on each processor and determine the starting point of each processors ownership 
297:      for global vector without redundancy */
298:   fromnglobal = 0;
299:   fa->offg[1] = 0;
300:   offt[1]     = 0;
301:   if (fa->comm[1]) {
302:     DAGetCorners(da2,&x,&y,0,&nx,&ny,0);
303:     offt[2] = nx*ny;
304:     if (y+ny == fa->r2g) {ny--;}  /* includes the ghost points on the upper side */
305:     fromnglobal += nx*ny;
306:     fa->offg[2] = fromnglobal;
307:   } else {
308:     offt[2] = 0;
309:     fa->offg[2] = 0;
310:   }
311:   if (fa->comm[2]) {
312:     DAGetCorners(da3,&x,&y,0,&nx,&ny,0);
313:     offt[0] = offt[2] + nx*ny;
314:     if (y+ny == fa->r2g) {ny--;}  /* includes the ghost points on the upper side */
315:     fromnglobal += nx*ny;
316:     fa->offg[0] = fromnglobal;
317:   } else {
318:     offt[0]     = offt[2];
319:     fa->offg[0] = fromnglobal;
320:   }
321:   if (fa->comm[0]) {
322:     DAGetCorners(da1,&x,&y,0,&nx,&ny,0);
323:     if (y == 0) {ny--;}  /* includes the ghost points on the lower side */
324:     fromnglobal += nx*ny;
325:   }
326:   MPI_Scan(&fromnglobal,&globalrstart,1,MPIU_INT,MPI_SUM,PETSC_COMM_WORLD);
327:   globalrstart -= fromnglobal;
328:   PetscSynchronizedPrintf(PETSC_COMM_WORLD,"[%d] Number of unknowns owned %d\n",rank,fromnglobal);
329:   PetscSynchronizedFlush(PETSC_COMM_WORLD);

331:   /* Get fromnatural number for each node */
332:   PetscMalloc((fromnglobal+1)*sizeof(PetscInt),&fromnatural);
333:   fromnglobal = 0;
334:   if (fa->comm[1]) {
335:     DAGetCorners(da2,&x,&y,0,&nx,&ny,0);
336:     if (y+ny == fa->r2g) {ny--;}  /* includes the ghost points on the upper side */
337:     fa->xg[1] = x; fa->yg[1] = y; fa->mg[1] = nx; fa->ng[1] = ny;
338:     DAGetGhostCorners(da2,&fa->xl[1],&fa->yl[1],0,&fa->ml[1],&fa->nl[1],0);
339:     for (j=0; j<ny; j++) {
340:       for (i=0; i<nx; i++) {
341:         fromnatural[fromnglobal++] = (fa->p1 - fa->p2)/2 + x + i + fa->p1*(y + j);
342:       }
343:     }
344:   }
345:   if (fa->comm[2]) {
346:     DAGetCorners(da3,&x,&y,0,&nx,&ny,0);
347:     if (y+ny == fa->r2g) {ny--;}  /* includes the ghost points on the upper side */
348:     fa->xg[2] = x; fa->yg[2] = y; fa->mg[2] = nx; fa->ng[2] = ny;
349:     DAGetGhostCorners(da3,&fa->xl[2],&fa->yl[2],0,&fa->ml[2],&fa->nl[2],0);
350:     for (j=0; j<ny; j++) {
351:       for (i=0; i<nx; i++) {
352:         if (x + i < (fa->p1 - fa->p2)/2) fromnatural[fromnglobal++] = x + i + fa->p1*(y + j);
353:         else fromnatural[fromnglobal++] = fa->p2 + x + i + fa->p1*(y + j);
354:       }
355:     }
356:   }
357:   if (fa->comm[0]) {
358:     DAGetCorners(da1,&x,&y,0,&nx,&ny,0);
359:     if (y == 0) {ny--;}  /* includes the ghost points on the lower side */
360:     else y--;
361:     fa->xg[0] = x; fa->yg[0] = y; fa->mg[0] = nx; fa->ng[0] = ny;
362:     DAGetGhostCorners(da1,&fa->xl[0],&fa->yl[0],0,&fa->ml[0],&fa->nl[0],0);
363:     for (j=0; j<ny; j++) {
364:       for (i=0; i<nx; i++) {
365:         fromnatural[fromnglobal++] = fa->p1*fa->r2 + x + i + fa->p1*(y + j);
366:       }
367:     }
368:   }
369:   /*PetscIntView(fromnglobal,fromnatural,PETSC_VIEWER_STDOUT_WORLD);*/
370:   AOCreateBasic(PETSC_COMM_WORLD,fromnglobal,fromnatural,0,&globalao);
371:   PetscFree(fromnatural);

373:   /* ---------------------------------------------------*/
374:   /* Create the scatter that updates 1 from 2 and 3 and 3 and 2 from 1 */
375:   /* currently handles stencil width of 1 ONLY */
376:   PetscMalloc(tonglobal*sizeof(PetscInt),&to);
377:   PetscMalloc(tonglobal*sizeof(PetscInt),&from);
378:   nscat = 0;
379:   if (fa->comm[1]) {
380:     DAGetCorners(da2,&x,&y,0,&nx,&ny,0);
381:     for (j=0; j<ny; j++) {
382:       for (i=0; i<nx; i++) {
383:         to[nscat] = from[nscat] = (fa->p1 - fa->p2)/2 + x + i + fa->p1*(y + j);nscat++;
384:       }
385:     }
386:   }
387:   if (fa->comm[2]) {
388:     DAGetCorners(da3,&x,&y,0,&nx,&ny,0);
389:     for (j=0; j<ny; j++) {
390:       for (i=0; i<nx; i++) {
391:         if (x + i < (fa->p1 - fa->p2)/2) {
392:           to[nscat]   = from[nscat] = x + i + fa->p1*(y + j);nscat++;
393:         } else {
394:           to[nscat]   = from[nscat] = fa->p2 + x + i + fa->p1*(y + j);nscat++;
395:         }
396:       }
397:     }
398:   }
399:   if (fa->comm[0]) {
400:     DAGetCorners(da1,&x,&y,0,&nx,&ny,0);
401:     for (j=0; j<ny; j++) {
402:       for (i=0; i<nx; i++) {
403:         to[nscat]     = fa->p1*fa->r2g + x + i + fa->p1*(y + j);
404:         from[nscat++] = fa->p1*(fa->r2 - 1) + x + i + fa->p1*(y + j);
405:       }
406:     }
407:   }
408:   AOApplicationToPetsc(toao,nscat,to);
409:   AOApplicationToPetsc(globalao,nscat,from);
410:   ISCreateGeneral(PETSC_COMM_WORLD,nscat,to,&tois);
411:   ISCreateGeneral(PETSC_COMM_WORLD,nscat,from,&globalis);
412:   PetscFree(to);
413:   PetscFree(from);
414:   VecCreateMPI(PETSC_COMM_WORLD,tonglobal,PETSC_DETERMINE,&tovec);
415:   VecCreateMPI(PETSC_COMM_WORLD,fromnglobal,PETSC_DETERMINE,&globalvec);
416:   VecScatterCreate(globalvec,globalis,tovec,tois,&vscat);
417:   ISDestroy(tois);
418:   ISDestroy(globalis);
419:   AODestroy(globalao);
420:   AODestroy(toao);

422:   /* fill up global vector without redundant values with PETSc global numbering */
423:   VecGetArray(globalvec,&globalarray);
424:   for (i=0; i<fromnglobal; i++) {
425:     globalarray[i] = globalrstart + i;
426:   }
427:   VecRestoreArray(globalvec,&globalarray);
428: 
429:   /* scatter PETSc global indices to redundant valueed array */
430:   VecScatterBegin(globalvec,tovec,INSERT_VALUES,SCATTER_FORWARD,vscat);
431:   VecScatterEnd(globalvec,tovec,INSERT_VALUES,SCATTER_FORWARD,vscat);
432: 
433:   /* Create local vector that is the concatenation of the local vectors */
434:   nlocal = 0;
435:   cntl1  = cntl2 = cntl3 = 0;
436:   if (fa->comm[1]) {
437:     VecGetSize(vl2,&cntl2);
438:     nlocal += cntl2;
439:   }
440:   if (fa->comm[2]) {
441:     VecGetSize(vl3,&cntl3);
442:     nlocal += cntl3;
443:   }
444:   if (fa->comm[0]) {
445:     VecGetSize(vl1,&cntl1);
446:     nlocal += cntl1;
447:   }
448:   fa->offl[0] = cntl2 + cntl3;
449:   fa->offl[1] = 0;
450:   fa->offl[2] = cntl2;
451:   VecCreateSeq(PETSC_COMM_SELF,nlocal,&localvec);
452: 
453:   /* cheat so that  vl1, vl2, vl3 shared array memory with localvec */
454:   VecGetArray(localvec,&localarray);
455:   VecGetArray(tovec,&toarray);
456:   if (fa->comm[1]) {
457:     VecPlaceArray(vl2,localarray+fa->offl[1]);
458:     VecPlaceArray(vg2,toarray+offt[1]);
459:     DAGlobalToLocalBegin(da2,vg2,INSERT_VALUES,vl2);
460:     DAGlobalToLocalEnd(da2,vg2,INSERT_VALUES,vl2);
461:     DARestoreGlobalVector(da2,&vg2);
462:   }
463:   if (fa->comm[2]) {
464:     VecPlaceArray(vl3,localarray+fa->offl[2]);
465:     VecPlaceArray(vg3,toarray+offt[2]);
466:     DAGlobalToLocalBegin(da3,vg3,INSERT_VALUES,vl3);
467:     DAGlobalToLocalEnd(da3,vg3,INSERT_VALUES,vl3);
468:     DARestoreGlobalVector(da3,&vg3);
469:   }
470:   if (fa->comm[0]) {
471:     VecPlaceArray(vl1,localarray+fa->offl[0]);
472:     VecPlaceArray(vg1,toarray+offt[0]);
473:     DAGlobalToLocalBegin(da1,vg1,INSERT_VALUES,vl1);
474:     DAGlobalToLocalEnd(da1,vg1,INSERT_VALUES,vl1);
475:     DARestoreGlobalVector(da1,&vg1);
476:   }
477:   VecRestoreArray(localvec,&localarray);
478:   VecRestoreArray(tovec,&toarray);

480:   /* no longer need the redundant vector and VecScatter to it */
481:   VecScatterDestroy(vscat);
482:   VecDestroy(tovec);

484:   /* Create final scatter that goes directly from globalvec to localvec */
485:   /* this is the one to be used in the application code */
486:   PetscMalloc(nlocal*sizeof(PetscInt),&indices);
487:   VecGetArray(localvec,&localarray);
488:   for (i=0; i<nlocal; i++) {
489:     indices[i] = (PetscInt) (2*localarray[i]);
490:   }
491:   VecRestoreArray(localvec,&localarray);
492:   ISCreateBlock(PETSC_COMM_WORLD,2,nlocal,indices,&is);
493:   PetscFree(indices);

495:   VecCreateSeq(PETSC_COMM_SELF,2*nlocal,&fa->l);
496:   VecCreateMPI(PETSC_COMM_WORLD,2*fromnglobal,PETSC_DETERMINE,&fa->g);

498:   VecScatterCreate(fa->g,is,fa->l,PETSC_NULL,&fa->vscat);
499:   ISDestroy(is);

501:   VecDestroy(globalvec);
502:   VecDestroy(localvec);
503:   if (fa->comm[0]) {
504:     DARestoreLocalVector(da1,&vl1);
505:     DADestroy(da1);
506:   }
507:   if (fa->comm[1]) {
508:     DARestoreLocalVector(da2,&vl2);
509:     DADestroy(da2);
510:   }
511:   if (fa->comm[2]) {
512:     DARestoreLocalVector(da3,&vl3);
513:     DADestroy(da3);
514:   }
515:   *infa = fa;
516:   return(0);
517: }

519: /* Crude graphics to test that the ghost points are properly updated */
520:  #include petscdraw.h

522: typedef struct {
523:   PetscInt     m[3],n[3];
524:   PetscScalar  *xy[3];
525: } ZoomCtx;

527: PetscErrorCode DrawPatch(PetscDraw draw,void *ctx)
528: {
529:   ZoomCtx        *zctx = (ZoomCtx*)ctx;
531:   PetscInt       m,n,i,j,id,k;
532:   PetscReal      x1,x2,x3,x4,y_1,y2,y3,y4;
533:   PetscScalar    *xy;

536:   for (k=0; k<3; k++) {
537:     m    = zctx->m[k];
538:     n    = zctx->n[k];
539:     xy   = zctx->xy[k];

541:     for (j=0; j<n-1; j++) {
542:       for (i=0; i<m-1; i++) {
543:         id = i+j*m;    x1 = xy[2*id];y_1 = xy[2*id+1];
544:         id = i+j*m+1;  x2 = xy[2*id];y2  = xy[2*id+1];
545:         id = i+j*m+1+m;x3 = xy[2*id];y3  = xy[2*id+1];
546:         id = i+j*m+m;  x4 = xy[2*id];y4  = xy[2*id+1];
547:         PetscDrawLine(draw,x1,y_1,x2,y2,PETSC_DRAW_BLACK);
548:         PetscDrawLine(draw,x2,y2,x3,y3,PETSC_DRAW_BLACK);
549:         PetscDrawLine(draw,x3,y3,x4,y4,PETSC_DRAW_BLACK);
550:         PetscDrawLine(draw,x4,y4,x1,y_1,PETSC_DRAW_BLACK);
551:       }
552:     }
553:   }
554:   PetscDrawFlush(draw);
555:   return(0);
556: }

558: PetscErrorCode DrawFA(FA fa,Vec v)
559: {
561:   PetscScalar    *va;
562:   ZoomCtx        zctx;
563:   PetscDraw      draw;
564:   PetscReal      xmint = 10000.0,xmaxt = -10000.0,ymint = 100000.0,ymaxt = -10000.0;
565:   PetscReal      xmin,xmax,ymin,ymax;
566:   PetscInt       i,vn,ln,j;

569:   VecGetArray(v,&va);
570:   VecGetSize(v,&vn);
571:   VecGetSize(fa->l,&ln);
572:   for (j=0; j<3; j++) {
573:     if (vn == ln) {
574:       zctx.xy[j] = va + 2*fa->offl[j];
575:       zctx.m[j]  = fa->ml[j];
576:       zctx.n[j]  = fa->nl[j];
577:     } else {
578:       zctx.xy[j] = va + 2*fa->offg[j];
579:       zctx.m[j]  = fa->mg[j];
580:       zctx.n[j]  = fa->ng[j];
581:     }
582:     for (i=0; i<zctx.m[j]*zctx.n[j]; i++) {
583:       if (zctx.xy[j][2*i] > xmax) xmax = zctx.xy[j][2*i];
584:       if (zctx.xy[j][2*i] < xmin) xmin = zctx.xy[j][2*i];
585:       if (zctx.xy[j][2*i+1] > ymax) ymax = zctx.xy[j][2*i+1];
586:       if (zctx.xy[j][2*i+1] < ymin) ymin = zctx.xy[j][2*i+1];
587:     }
588:   }
589:   MPI_Allreduce(&xmin,&xmint,1,MPI_DOUBLE,MPI_MIN,PETSC_COMM_WORLD);
590:   MPI_Allreduce(&xmax,&xmaxt,1,MPI_DOUBLE,MPI_MAX,PETSC_COMM_WORLD);
591:   MPI_Allreduce(&ymin,&ymint,1,MPI_DOUBLE,MPI_MIN,PETSC_COMM_WORLD);
592:   MPI_Allreduce(&ymax,&ymaxt,1,MPI_DOUBLE,MPI_MAX,PETSC_COMM_WORLD);
593:   xmin = xmint - .2*(xmaxt - xmint);
594:   xmax = xmaxt + .2*(xmaxt - xmint);
595:   ymin = ymint - .2*(ymaxt - ymint);
596:   ymax = ymaxt + .2*(ymaxt - ymint);
597:   PetscDrawOpenX(PETSC_COMM_WORLD,0,"meshes",PETSC_DECIDE,PETSC_DECIDE,700,700,&draw);
598:   PetscDrawSetCoordinates(draw,xmin,ymin,xmax,ymax);
599:   PetscDrawZoom(draw,DrawPatch,&zctx);
600:   VecRestoreArray(v,&va);
601:   PetscDrawDestroy(draw);
602:   return(0);
603: }

605: /* crude mappings from rectangular arrays to the true geometry. These are ONLY for testing!
606:    they will not be used the actual code */
607: PetscErrorCode FAMapRegion3(FA fa,Vec g)
608: {
610:   PetscReal      R = 1.0,Rscale,Ascale;
611:   PetscInt       i,k,x,y,m,n;
612:   Field          **ga;

615:   Rscale = R/(fa->r2-1);
616:   Ascale = 2.0*PETSC_PI/(3.0*(fa->p1 - fa->p2 - 1));

618:   FAGetGlobalCorners(fa,2,&x,&y,&m,&n);
619:   FAGetGlobalArray(fa,g,2,&ga);
620:   for (k=y; k<y+n; k++) {
621:     for (i=x; i<x+m; i++) {
622:       ga[k][i].X = (R + k*Rscale)*PetscCosScalar(1.*PETSC_PI/6. + i*Ascale);
623:       ga[k][i].Y = (R + k*Rscale)*PetscSinScalar(1.*PETSC_PI/6. + i*Ascale) - 4.*R;
624:     }
625:   }
626:   FARestoreGlobalArray(fa,g,2,&ga);
627:   return(0);
628: }

630: PetscErrorCode FAMapRegion2(FA fa,Vec g)
631: {
633:   PetscReal      R = 1.0,Rscale,Ascale;
634:   PetscInt       i,k,x,y,m,n;
635:   Field          **ga;

638:   Rscale = R/(fa->r2-1);
639:   Ascale = 2.0*PETSC_PI/fa->p2;

641:   FAGetGlobalCorners(fa,1,&x,&y,&m,&n);
642:   FAGetGlobalArray(fa,g,1,&ga);
643:   for (k=y; k<y+n; k++) {
644:     for (i=x; i<x+m; i++) {
645:       ga[k][i].X = (R + k*Rscale)*PetscCosScalar(i*Ascale - PETSC_PI/2.0);
646:       ga[k][i].Y = (R + k*Rscale)*PetscSinScalar(i*Ascale - PETSC_PI/2.0);
647:     }
648:   }
649:   FARestoreGlobalArray(fa,g,1,&ga);
650:   return(0);
651: }

653: PetscErrorCode FAMapRegion1(FA fa,Vec g)
654: {
656:   PetscReal      R = 1.0,Rscale,Ascale1,Ascale3;
657:   PetscInt       i,k,x,y,m,n;
658:   Field          **ga;

661:   Rscale  = R/(fa->r1-1);
662:   Ascale1 = 2.0*PETSC_PI/fa->p2;
663:   Ascale3 = 2.0*PETSC_PI/(3.0*(fa->p1 - fa->p2 - 1));

665:   FAGetGlobalCorners(fa,0,&x,&y,&m,&n);
666:   FAGetGlobalArray(fa,g,0,&ga);

668:   /* This mapping is WRONG! Not sure how to do it so I've done a poor job of
669:      it. You can see that the grid connections are correct. */
670:   for (k=y; k<y+n; k++) {
671:     for (i=x; i<x+m; i++) {
672:       if (i < (fa->p1-fa->p2)/2) {
673:         ga[k][i].X = (2.0*R + k*Rscale)*PetscCosScalar(i*Ascale3);
674:         ga[k][i].Y = (2.0*R + k*Rscale)*PetscSinScalar(i*Ascale3) - 4.*R;
675:       } else if (i > fa->p2 + (fa->p1 - fa->p2)/2) {
676:         ga[k][i].X = (2.0*R + k*Rscale)*PetscCosScalar(PETSC_PI+i*Ascale3);
677:         ga[k][i].Y = (2.0*R + k*Rscale)*PetscSinScalar(PETSC_PI+i*Ascale3) - 4.*R;
678:       } else {
679:         ga[k][i].X = (2.*R + k*Rscale)*PetscCosScalar((i-(fa->p1-fa->p2)/2)*Ascale1 - PETSC_PI/2.0);
680:         ga[k][i].Y = (2.*R + k*Rscale)*PetscSinScalar((i-(fa->p1-fa->p2)/2)*Ascale1 - PETSC_PI/2.0);
681:       }
682:     }
683:   }
684:   FARestoreGlobalArray(fa,g,0,&ga);
685:   return(0);
686: }

688: /* Simple test to check that the ghost points are properly updated */
689: PetscErrorCode FATest(FA fa)
690: {
692:   Vec            l,g;
693:   Field          **la;
694:   PetscInt       x,y,m,n,j,i,k,p;
695:   PetscMPIInt    rank;

698:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

700:   FAGetGlobalVector(fa,&g);
701:   FAGetLocalVector(fa,&l);

703:   /* fill up global vector of one region at a time with ITS logical coordinates, then update LOCAL
704:      vector; print local vectors to confirm they are correctly filled */
705:   for (j=0; j<3; j++) {
706:     VecSet(g,0.0);
707:     FAGetGlobalCorners(fa,j,&x,&y,&m,&n);
708:     PetscPrintf(PETSC_COMM_WORLD,"\nFilling global region %d, showing local results \n",j+1);
709:     FAGetGlobalArray(fa,g,j,&la);
710:     for (k=y; k<y+n; k++) {
711:       for (i=x; i<x+m; i++) {
712:         la[k][i].X = i;
713:         la[k][i].Y = k;
714:       }
715:     }
716:     FARestoreGlobalArray(fa,g,j,&la);

718:     FAGlobalToLocal(fa,g,l);
719:     DrawFA(fa,g);
720:     DrawFA(fa,l);

722:     for (p=0; p<3; p++) {
723:       FAGetLocalCorners(fa,p,&x,&y,&m,&n);
724:       FAGetLocalArray(fa,l,p,&la);
725:       PetscSynchronizedPrintf(PETSC_COMM_WORLD,"\n[%d] Local array for region %d \n",rank,p+1);
726:       for (k=y+n-1; k>=y; k--) { /* print in reverse order to match diagram in paper */
727:         for (i=x; i<x+m; i++) {
728:           PetscSynchronizedPrintf(PETSC_COMM_WORLD,"(%G,%G) ",la[k][i].X,la[k][i].Y);
729:         }
730:         PetscSynchronizedPrintf(PETSC_COMM_WORLD,"\n");
731:       }
732:       FARestoreLocalArray(fa,l,p,&la);
733:       PetscSynchronizedFlush(PETSC_COMM_WORLD);
734:     }
735:   }
736:   VecDestroy(g);
737:   VecDestroy(l);
738:   return(0);
739: }

743: int main(int argc,char **argv)
744: {
745:   FA             fa;
747:   Vec            g,l;

749:   PetscInitialize(&argc,&argv,0,help);

751:   FACreate(&fa);
752:   /* FATest(fa);*/

754:   FAGetGlobalVector(fa,&g);
755:   FAGetLocalVector(fa,&l);

757:   FAMapRegion1(fa,g);
758:   FAMapRegion2(fa,g);
759:   FAMapRegion3(fa,g);

761:   FAGlobalToLocal(fa,g,l);
762:   DrawFA(fa,g);
763:   DrawFA(fa,l);

765:   VecDestroy(g);
766:   VecDestroy(l);
767:   FADestroy(fa);

769:   PetscFinalize();
770:   return 0;
771: }