Actual source code: da2.c

petsc-3.4.4 2014-03-13
  2: #include <petsc-private/dmdaimpl.h>    /*I   "petscdmda.h"   I*/
  3: #include <petscdraw.h>

  7: PetscErrorCode DMView_DA_2d(DM da,PetscViewer viewer)
  8: {
 10:   PetscMPIInt    rank;
 11:   PetscBool      iascii,isdraw,isbinary;
 12:   DM_DA          *dd = (DM_DA*)da->data;
 13: #if defined(PETSC_HAVE_MATLAB_ENGINE)
 14:   PetscBool ismatlab;
 15: #endif

 18:   MPI_Comm_rank(PetscObjectComm((PetscObject)da),&rank);

 20:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
 21:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
 22:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
 23: #if defined(PETSC_HAVE_MATLAB_ENGINE)
 24:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERMATLAB,&ismatlab);
 25: #endif
 26:   if (iascii) {
 27:     PetscViewerFormat format;

 29:     PetscViewerGetFormat(viewer, &format);
 30:     if (format != PETSC_VIEWER_ASCII_VTK && format != PETSC_VIEWER_ASCII_VTK_CELL) {
 31:       DMDALocalInfo info;
 32:       DMDAGetLocalInfo(da,&info);
 33:       PetscViewerASCIISynchronizedAllow(viewer,PETSC_TRUE);
 34:       PetscViewerASCIISynchronizedPrintf(viewer,"Processor [%d] M %D N %D m %D n %D w %D s %D\n",rank,dd->M,dd->N,dd->m,dd->n,dd->w,dd->s);
 35:       PetscViewerASCIISynchronizedPrintf(viewer,"X range of indices: %D %D, Y range of indices: %D %D\n",info.xs,info.xs+info.xm,info.ys,info.ys+info.ym);
 36:       PetscViewerFlush(viewer);
 37:       PetscViewerASCIISynchronizedAllow(viewer,PETSC_FALSE);
 38:     } else {
 39:       DMView_DA_VTK(da,viewer);
 40:     }
 41:   } else if (isdraw) {
 42:     PetscDraw draw;
 43:     double    ymin = -1*dd->s-1,ymax = dd->N+dd->s;
 44:     double    xmin = -1*dd->s-1,xmax = dd->M+dd->s;
 45:     double    x,y;
 46:     PetscInt  base,*idx;
 47:     char      node[10];
 48:     PetscBool isnull;

 50:     PetscViewerDrawGetDraw(viewer,0,&draw);
 51:     PetscDrawIsNull(draw,&isnull); if (isnull) return(0);
 52:     if (!da->coordinates) {
 53:       PetscDrawSetCoordinates(draw,xmin,ymin,xmax,ymax);
 54:     }
 55:     PetscDrawSynchronizedClear(draw);

 57:     /* first processor draw all node lines */
 58:     if (!rank) {
 59:       ymin = 0.0; ymax = dd->N - 1;
 60:       for (xmin=0; xmin<dd->M; xmin++) {
 61:         PetscDrawLine(draw,xmin,ymin,xmin,ymax,PETSC_DRAW_BLACK);
 62:       }
 63:       xmin = 0.0; xmax = dd->M - 1;
 64:       for (ymin=0; ymin<dd->N; ymin++) {
 65:         PetscDrawLine(draw,xmin,ymin,xmax,ymin,PETSC_DRAW_BLACK);
 66:       }
 67:     }
 68:     PetscDrawSynchronizedFlush(draw);
 69:     PetscDrawPause(draw);

 71:     /* draw my box */
 72:     ymin = dd->ys; ymax = dd->ye - 1; xmin = dd->xs/dd->w;
 73:     xmax =(dd->xe-1)/dd->w;
 74:     PetscDrawLine(draw,xmin,ymin,xmax,ymin,PETSC_DRAW_RED);
 75:     PetscDrawLine(draw,xmin,ymin,xmin,ymax,PETSC_DRAW_RED);
 76:     PetscDrawLine(draw,xmin,ymax,xmax,ymax,PETSC_DRAW_RED);
 77:     PetscDrawLine(draw,xmax,ymin,xmax,ymax,PETSC_DRAW_RED);

 79:     /* put in numbers */
 80:     base = (dd->base)/dd->w;
 81:     for (y=ymin; y<=ymax; y++) {
 82:       for (x=xmin; x<=xmax; x++) {
 83:         sprintf(node,"%d",(int)base++);
 84:         PetscDrawString(draw,x,y,PETSC_DRAW_BLACK,node);
 85:       }
 86:     }

 88:     PetscDrawSynchronizedFlush(draw);
 89:     PetscDrawPause(draw);
 90:     /* overlay ghost numbers, useful for error checking */
 91:     /* put in numbers */

 93:     base = 0; idx = dd->idx;
 94:     ymin = dd->Ys; ymax = dd->Ye; xmin = dd->Xs; xmax = dd->Xe;
 95:     for (y=ymin; y<ymax; y++) {
 96:       for (x=xmin; x<xmax; x++) {
 97:         if ((base % dd->w) == 0) {
 98:           sprintf(node,"%d",(int)(idx[base]/dd->w));
 99:           PetscDrawString(draw,x/dd->w,y,PETSC_DRAW_BLUE,node);
100:         }
101:         base++;
102:       }
103:     }
104:     PetscDrawSynchronizedFlush(draw);
105:     PetscDrawPause(draw);
106:   } else if (isbinary) {
107:     DMView_DA_Binary(da,viewer);
108: #if defined(PETSC_HAVE_MATLAB_ENGINE)
109:   } else if (ismatlab) {
110:     DMView_DA_Matlab(da,viewer);
111: #endif
112:   }
113:   return(0);
114: }

116: /*
117:       M is number of grid points
118:       m is number of processors

120: */
123: PetscErrorCode  DMDASplitComm2d(MPI_Comm comm,PetscInt M,PetscInt N,PetscInt sw,MPI_Comm *outcomm)
124: {
126:   PetscInt       m,n = 0,x = 0,y = 0;
127:   PetscMPIInt    size,csize,rank;

130:   MPI_Comm_size(comm,&size);
131:   MPI_Comm_rank(comm,&rank);

133:   csize = 4*size;
134:   do {
135:     if (csize % 4) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Cannot split communicator of size %d tried %d %D %D",size,csize,x,y);
136:     csize = csize/4;

138:     m = (PetscInt)(0.5 + PetscSqrtReal(((PetscReal)M)*((PetscReal)csize)/((PetscReal)N)));
139:     if (!m) m = 1;
140:     while (m > 0) {
141:       n = csize/m;
142:       if (m*n == csize) break;
143:       m--;
144:     }
145:     if (M > N && m < n) {PetscInt _m = m; m = n; n = _m;}

147:     x = M/m + ((M % m) > ((csize-1) % m));
148:     y = (N + (csize-1)/m)/n;
149:   } while ((x < 4 || y < 4) && csize > 1);
150:   if (size != csize) {
151:     MPI_Group   entire_group,sub_group;
152:     PetscMPIInt i,*groupies;

154:     MPI_Comm_group(comm,&entire_group);
155:     PetscMalloc(csize*sizeof(PetscInt),&groupies);
156:     for (i=0; i<csize; i++) {
157:       groupies[i] = (rank/csize)*csize + i;
158:     }
159:     MPI_Group_incl(entire_group,csize,groupies,&sub_group);
160:     PetscFree(groupies);
161:     MPI_Comm_create(comm,sub_group,outcomm);
162:     MPI_Group_free(&entire_group);
163:     MPI_Group_free(&sub_group);
164:     PetscInfo1(0,"DMDASplitComm2d:Creating redundant coarse problems of size %d\n",csize);
165:   } else {
166:     *outcomm = comm;
167:   }
168:   return(0);
169: }

171: #if defined(new)
174: /*
175:   DMDAGetDiagonal_MFFD - Gets the diagonal for a matrix free matrix where local
176:     function lives on a DMDA

178:         y ~= (F(u + ha) - F(u))/h,
179:   where F = nonlinear function, as set by SNESSetFunction()
180:         u = current iterate
181:         h = difference interval
182: */
183: PetscErrorCode DMDAGetDiagonal_MFFD(DM da,Vec U,Vec a)
184: {
185:   PetscScalar    h,*aa,*ww,v;
186:   PetscReal      epsilon = PETSC_SQRT_MACHINE_EPSILON,umin = 100.0*PETSC_SQRT_MACHINE_EPSILON;
188:   PetscInt       gI,nI;
189:   MatStencil     stencil;
190:   DMDALocalInfo  info;

193:   (*ctx->func)(0,U,a,ctx->funcctx);
194:   (*ctx->funcisetbase)(U,ctx->funcctx);

196:   VecGetArray(U,&ww);
197:   VecGetArray(a,&aa);

199:   nI = 0;
200:   h  = ww[gI];
201:   if (h == 0.0) h = 1.0;
202:   if (PetscAbsScalar(h) < umin && PetscRealPart(h) >= 0.0) h = umin;
203:   else if (PetscRealPart(h) < 0.0 && PetscAbsScalar(h) < umin) h = -umin;
204:   h *= epsilon;

206:   ww[gI] += h;
207:   (*ctx->funci)(i,w,&v,ctx->funcctx);
208:   aa[nI]  = (v - aa[nI])/h;
209:   ww[gI] -= h;
210:   nI++;

212:   VecRestoreArray(U,&ww);
213:   VecRestoreArray(a,&aa);
214:   return(0);
215: }
216: #endif

220: PetscErrorCode  DMSetUp_DA_2D(DM da)
221: {
222:   DM_DA            *dd = (DM_DA*)da->data;
223:   const PetscInt   M            = dd->M;
224:   const PetscInt   N            = dd->N;
225:   PetscInt         m            = dd->m;
226:   PetscInt         n            = dd->n;
227:   const PetscInt   dof          = dd->w;
228:   const PetscInt   s            = dd->s;
229:   DMDABoundaryType bx           = dd->bx;
230:   DMDABoundaryType by           = dd->by;
231:   DMDAStencilType  stencil_type = dd->stencil_type;
232:   PetscInt         *lx          = dd->lx;
233:   PetscInt         *ly          = dd->ly;
234:   MPI_Comm         comm;
235:   PetscMPIInt      rank,size;
236:   PetscInt         xs,xe,ys,ye,x,y,Xs,Xe,Ys,Ye,start,end,IXs,IXe,IYs,IYe;
237:   PetscInt         up,down,left,right,i,n0,n1,n2,n3,n5,n6,n7,n8,*idx,nn,*idx_cpy;
238:   const PetscInt   *idx_full;
239:   PetscInt         xbase,*bases,*ldims,j,x_t,y_t,s_t,base,count;
240:   PetscInt         s_x,s_y; /* s proportionalized to w */
241:   PetscInt         sn0 = 0,sn2 = 0,sn6 = 0,sn8 = 0;
242:   Vec              local,global;
243:   VecScatter       ltog,gtol;
244:   IS               to,from,ltogis;
245:   PetscErrorCode   ierr;

248:   if (stencil_type == DMDA_STENCIL_BOX && (bx == DMDA_BOUNDARY_MIRROR || by == DMDA_BOUNDARY_MIRROR)) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Mirror boundary and box stencil");
249:   PetscObjectGetComm((PetscObject)da,&comm);
250: #if !defined(PETSC_USE_64BIT_INDICES)
251:   if (((Petsc64bitInt) M)*((Petsc64bitInt) N)*((Petsc64bitInt) dof) > (Petsc64bitInt) PETSC_MPI_INT_MAX) SETERRQ3(comm,PETSC_ERR_INT_OVERFLOW,"Mesh of %D by %D by %D (dof) is too large for 32 bit indices",M,N,dof);
252: #endif

254:   if (dof < 1) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Must have 1 or more degrees of freedom per node: %D",dof);
255:   if (s < 0) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Stencil width cannot be negative: %D",s);

257:   MPI_Comm_size(comm,&size);
258:   MPI_Comm_rank(comm,&rank);

260:   if (m != PETSC_DECIDE) {
261:     if (m < 1) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Non-positive number of processors in X direction: %D",m);
262:     else if (m > size) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"Too many processors in X direction: %D %d",m,size);
263:   }
264:   if (n != PETSC_DECIDE) {
265:     if (n < 1) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Non-positive number of processors in Y direction: %D",n);
266:     else if (n > size) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"Too many processors in Y direction: %D %d",n,size);
267:   }

269:   if (m == PETSC_DECIDE || n == PETSC_DECIDE) {
270:     if (n != PETSC_DECIDE) {
271:       m = size/n;
272:     } else if (m != PETSC_DECIDE) {
273:       n = size/m;
274:     } else {
275:       /* try for squarish distribution */
276:       m = (PetscInt)(0.5 + PetscSqrtReal(((PetscReal)M)*((PetscReal)size)/((PetscReal)N)));
277:       if (!m) m = 1;
278:       while (m > 0) {
279:         n = size/m;
280:         if (m*n == size) break;
281:         m--;
282:       }
283:       if (M > N && m < n) {PetscInt _m = m; m = n; n = _m;}
284:     }
285:     if (m*n != size) SETERRQ(comm,PETSC_ERR_PLIB,"Unable to create partition, check the size of the communicator and input m and n ");
286:   } else if (m*n != size) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"Given Bad partition");

288:   if (M < m) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"Partition in x direction is too fine! %D %D",M,m);
289:   if (N < n) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"Partition in y direction is too fine! %D %D",N,n);

291:   /*
292:      Determine locally owned region
293:      xs is the first local node number, x is the number of local nodes
294:   */
295:   if (!lx) {
296:     PetscMalloc(m*sizeof(PetscInt), &dd->lx);
297:     lx   = dd->lx;
298:     for (i=0; i<m; i++) {
299:       lx[i] = M/m + ((M % m) > i);
300:     }
301:   }
302:   x  = lx[rank % m];
303:   xs = 0;
304:   for (i=0; i<(rank % m); i++) {
305:     xs += lx[i];
306:   }
307: #if defined(PETSC_USE_DEBUG)
308:   left = xs;
309:   for (i=(rank % m); i<m; i++) {
310:     left += lx[i];
311:   }
312:   if (left != M) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Sum of lx across processors not equal to M: %D %D",left,M);
313: #endif

315:   /*
316:      Determine locally owned region
317:      ys is the first local node number, y is the number of local nodes
318:   */
319:   if (!ly) {
320:     PetscMalloc(n*sizeof(PetscInt), &dd->ly);
321:     ly   = dd->ly;
322:     for (i=0; i<n; i++) {
323:       ly[i] = N/n + ((N % n) > i);
324:     }
325:   }
326:   y  = ly[rank/m];
327:   ys = 0;
328:   for (i=0; i<(rank/m); i++) {
329:     ys += ly[i];
330:   }
331: #if defined(PETSC_USE_DEBUG)
332:   left = ys;
333:   for (i=(rank/m); i<n; i++) {
334:     left += ly[i];
335:   }
336:   if (left != N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Sum of ly across processors not equal to N: %D %D",left,N);
337: #endif

339:   /*
340:    check if the scatter requires more than one process neighbor or wraps around
341:    the domain more than once
342:   */
343:   if ((x < s) && ((m > 1) || (bx == DMDA_BOUNDARY_PERIODIC))) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Local x-width of domain x %D is smaller than stencil width s %D",x,s);
344:   if ((y < s) && ((n > 1) || (by == DMDA_BOUNDARY_PERIODIC))) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Local y-width of domain y %D is smaller than stencil width s %D",y,s);
345:   xe = xs + x;
346:   ye = ys + y;

348:   /* determine ghost region (Xs) and region scattered into (IXs)  */
349:   if (xs-s > 0) {
350:     Xs = xs - s; IXs = xs - s;
351:   } else {
352:     if (bx) {
353:       Xs = xs - s;
354:     } else {
355:       Xs = 0;
356:     }
357:     IXs = 0;
358:   }
359:   if (xe+s <= M) {
360:     Xe = xe + s; IXe = xe + s;
361:   } else {
362:     if (bx) {
363:       Xs = xs - s; Xe = xe + s;
364:     } else {
365:       Xe = M;
366:     }
367:     IXe = M;
368:   }

370:   if (bx == DMDA_BOUNDARY_PERIODIC || bx == DMDA_BOUNDARY_MIRROR) {
371:     IXs = xs - s;
372:     IXe = xe + s;
373:     Xs  = xs - s;
374:     Xe  = xe + s;
375:   }

377:   if (ys-s > 0) {
378:     Ys = ys - s; IYs = ys - s;
379:   } else {
380:     if (by) {
381:       Ys = ys - s;
382:     } else {
383:       Ys = 0;
384:     }
385:     IYs = 0;
386:   }
387:   if (ye+s <= N) {
388:     Ye = ye + s; IYe = ye + s;
389:   } else {
390:     if (by) {
391:       Ye = ye + s;
392:     } else {
393:       Ye = N;
394:     }
395:     IYe = N;
396:   }

398:   if (by == DMDA_BOUNDARY_PERIODIC || by == DMDA_BOUNDARY_MIRROR) {
399:     IYs = ys - s;
400:     IYe = ye + s;
401:     Ys  = ys - s;
402:     Ye  = ye + s;
403:   }

405:   /* stencil length in each direction */
406:   s_x = s;
407:   s_y = s;

409:   /* determine starting point of each processor */
410:   nn       = x*y;
411:   PetscMalloc2(size+1,PetscInt,&bases,size,PetscInt,&ldims);
412:   MPI_Allgather(&nn,1,MPIU_INT,ldims,1,MPIU_INT,comm);
413:   bases[0] = 0;
414:   for (i=1; i<=size; i++) {
415:     bases[i] = ldims[i-1];
416:   }
417:   for (i=1; i<=size; i++) {
418:     bases[i] += bases[i-1];
419:   }
420:   base = bases[rank]*dof;

422:   /* allocate the base parallel and sequential vectors */
423:   dd->Nlocal = x*y*dof;
424:   VecCreateMPIWithArray(comm,dof,dd->Nlocal,PETSC_DECIDE,0,&global);
425:   dd->nlocal = (Xe-Xs)*(Ye-Ys)*dof;
426:   VecCreateSeqWithArray(PETSC_COMM_SELF,dof,dd->nlocal,0,&local);

428:   /* generate appropriate vector scatters */
429:   /* local to global inserts non-ghost point region into global */
430:   VecGetOwnershipRange(global,&start,&end);
431:   ISCreateStride(comm,x*y*dof,start,1,&to);

433:   PetscMalloc(x*y*sizeof(PetscInt),&idx);
434:   left  = xs - Xs; right = left + x;
435:   down  = ys - Ys; up = down + y;
436:   count = 0;
437:   for (i=down; i<up; i++) {
438:     for (j=left; j<right; j++) {
439:       idx[count++] = i*(Xe-Xs) + j;
440:     }
441:   }

443:   ISCreateBlock(comm,dof,count,idx,PETSC_OWN_POINTER,&from);
444:   VecScatterCreate(local,from,global,to,&ltog);
445:   PetscLogObjectParent(dd,ltog);
446:   ISDestroy(&from);
447:   ISDestroy(&to);

449:   /* global to local must include ghost points within the domain,
450:      but not ghost points outside the domain that aren't periodic */
451:   if (stencil_type == DMDA_STENCIL_BOX) {
452:     count = (IXe-IXs)*(IYe-IYs);
453:     PetscMalloc(count*sizeof(PetscInt),&idx);

455:     left  = IXs - Xs; right = left + (IXe-IXs);
456:     down  = IYs - Ys; up = down + (IYe-IYs);
457:     count = 0;
458:     for (i=down; i<up; i++) {
459:       for (j=left; j<right; j++) {
460:         idx[count++] = j + i*(Xe-Xs);
461:       }
462:     }
463:     ISCreateBlock(comm,dof,count,idx,PETSC_OWN_POINTER,&to);

465:   } else {
466:     /* must drop into cross shape region */
467:     /*       ---------|
468:             |  top    |
469:          |---         ---| up
470:          |   middle      |
471:          |               |
472:          ----         ---- down
473:             | bottom  |
474:             -----------
475:          Xs xs        xe Xe */
476:     count = (ys-IYs)*x + y*(IXe-IXs) + (IYe-ye)*x;
477:     PetscMalloc(count*sizeof(PetscInt),&idx);

479:     left  = xs - Xs; right = left + x;
480:     down  = ys - Ys; up = down + y;
481:     count = 0;
482:     /* bottom */
483:     for (i=(IYs-Ys); i<down; i++) {
484:       for (j=left; j<right; j++) {
485:         idx[count++] = j + i*(Xe-Xs);
486:       }
487:     }
488:     /* middle */
489:     for (i=down; i<up; i++) {
490:       for (j=(IXs-Xs); j<(IXe-Xs); j++) {
491:         idx[count++] = j + i*(Xe-Xs);
492:       }
493:     }
494:     /* top */
495:     for (i=up; i<up+IYe-ye; i++) {
496:       for (j=left; j<right; j++) {
497:         idx[count++] = j + i*(Xe-Xs);
498:       }
499:     }
500:     ISCreateBlock(comm,dof,count,idx,PETSC_OWN_POINTER,&to);
501:   }


504:   /* determine who lies on each side of us stored in    n6 n7 n8
505:                                                         n3    n5
506:                                                         n0 n1 n2
507:   */

509:   /* Assume the Non-Periodic Case */
510:   n1 = rank - m;
511:   if (rank % m) {
512:     n0 = n1 - 1;
513:   } else {
514:     n0 = -1;
515:   }
516:   if ((rank+1) % m) {
517:     n2 = n1 + 1;
518:     n5 = rank + 1;
519:     n8 = rank + m + 1; if (n8 >= m*n) n8 = -1;
520:   } else {
521:     n2 = -1; n5 = -1; n8 = -1;
522:   }
523:   if (rank % m) {
524:     n3 = rank - 1;
525:     n6 = n3 + m; if (n6 >= m*n) n6 = -1;
526:   } else {
527:     n3 = -1; n6 = -1;
528:   }
529:   n7 = rank + m; if (n7 >= m*n) n7 = -1;

531:   if (bx == DMDA_BOUNDARY_PERIODIC && by == DMDA_BOUNDARY_PERIODIC) {
532:     /* Modify for Periodic Cases */
533:     /* Handle all four corners */
534:     if ((n6 < 0) && (n7 < 0) && (n3 < 0)) n6 = m-1;
535:     if ((n8 < 0) && (n7 < 0) && (n5 < 0)) n8 = 0;
536:     if ((n2 < 0) && (n5 < 0) && (n1 < 0)) n2 = size-m;
537:     if ((n0 < 0) && (n3 < 0) && (n1 < 0)) n0 = size-1;

539:     /* Handle Top and Bottom Sides */
540:     if (n1 < 0) n1 = rank + m * (n-1);
541:     if (n7 < 0) n7 = rank - m * (n-1);
542:     if ((n3 >= 0) && (n0 < 0)) n0 = size - m + rank - 1;
543:     if ((n3 >= 0) && (n6 < 0)) n6 = (rank%m)-1;
544:     if ((n5 >= 0) && (n2 < 0)) n2 = size - m + rank + 1;
545:     if ((n5 >= 0) && (n8 < 0)) n8 = (rank%m)+1;

547:     /* Handle Left and Right Sides */
548:     if (n3 < 0) n3 = rank + (m-1);
549:     if (n5 < 0) n5 = rank - (m-1);
550:     if ((n1 >= 0) && (n0 < 0)) n0 = rank-1;
551:     if ((n1 >= 0) && (n2 < 0)) n2 = rank-2*m+1;
552:     if ((n7 >= 0) && (n6 < 0)) n6 = rank+2*m-1;
553:     if ((n7 >= 0) && (n8 < 0)) n8 = rank+1;
554:   } else if (by == DMDA_BOUNDARY_PERIODIC) {  /* Handle Top and Bottom Sides */
555:     if (n1 < 0) n1 = rank + m * (n-1);
556:     if (n7 < 0) n7 = rank - m * (n-1);
557:     if ((n3 >= 0) && (n0 < 0)) n0 = size - m + rank - 1;
558:     if ((n3 >= 0) && (n6 < 0)) n6 = (rank%m)-1;
559:     if ((n5 >= 0) && (n2 < 0)) n2 = size - m + rank + 1;
560:     if ((n5 >= 0) && (n8 < 0)) n8 = (rank%m)+1;
561:   } else if (bx == DMDA_BOUNDARY_PERIODIC) { /* Handle Left and Right Sides */
562:     if (n3 < 0) n3 = rank + (m-1);
563:     if (n5 < 0) n5 = rank - (m-1);
564:     if ((n1 >= 0) && (n0 < 0)) n0 = rank-1;
565:     if ((n1 >= 0) && (n2 < 0)) n2 = rank-2*m+1;
566:     if ((n7 >= 0) && (n6 < 0)) n6 = rank+2*m-1;
567:     if ((n7 >= 0) && (n8 < 0)) n8 = rank+1;
568:   }

570:   PetscMalloc(9*sizeof(PetscInt),&dd->neighbors);

572:   dd->neighbors[0] = n0;
573:   dd->neighbors[1] = n1;
574:   dd->neighbors[2] = n2;
575:   dd->neighbors[3] = n3;
576:   dd->neighbors[4] = rank;
577:   dd->neighbors[5] = n5;
578:   dd->neighbors[6] = n6;
579:   dd->neighbors[7] = n7;
580:   dd->neighbors[8] = n8;

582:   if (stencil_type == DMDA_STENCIL_STAR) {
583:     /* save corner processor numbers */
584:     sn0 = n0; sn2 = n2; sn6 = n6; sn8 = n8;
585:     n0  = n2 = n6 = n8 = -1;
586:   }

588:   PetscMalloc((Xe-Xs)*(Ye-Ys)*sizeof(PetscInt),&idx);
589:   PetscLogObjectMemory(da,(Xe-Xs)*(Ye-Ys)*sizeof(PetscInt));

591:   nn = 0;
592:   xbase = bases[rank];
593:   for (i=1; i<=s_y; i++) {
594:     if (n0 >= 0) { /* left below */
595:       x_t = lx[n0 % m];
596:       y_t = ly[(n0/m)];
597:       s_t = bases[n0] + x_t*y_t - (s_y-i)*x_t - s_x;
598:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
599:     }

601:     if (n1 >= 0) { /* directly below */
602:       x_t = x;
603:       y_t = ly[(n1/m)];
604:       s_t = bases[n1] + x_t*y_t - (s_y+1-i)*x_t;
605:       for (j=0; j<x_t; j++) idx[nn++] = s_t++;
606:     } else if (by == DMDA_BOUNDARY_MIRROR) {
607:       for (j=0; j<x; j++) idx[nn++] = bases[rank] + x*(s_y - i + 1)  + j;
608:     }

610:     if (n2 >= 0) { /* right below */
611:       x_t = lx[n2 % m];
612:       y_t = ly[(n2/m)];
613:       s_t = bases[n2] + x_t*y_t - (s_y+1-i)*x_t;
614:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
615:     }
616:   }

618:   for (i=0; i<y; i++) {
619:     if (n3 >= 0) { /* directly left */
620:       x_t = lx[n3 % m];
621:       /* y_t = y; */
622:       s_t = bases[n3] + (i+1)*x_t - s_x;
623:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
624:     } else if (bx == DMDA_BOUNDARY_MIRROR) {
625:       for (j=0; j<s_x; j++) idx[nn++] = bases[rank] + x*i + s_x - j;
626:     }

628:     for (j=0; j<x; j++) idx[nn++] = xbase++; /* interior */

630:     if (n5 >= 0) { /* directly right */
631:       x_t = lx[n5 % m];
632:       /* y_t = y; */
633:       s_t = bases[n5] + (i)*x_t;
634:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
635:     } else if (bx == DMDA_BOUNDARY_MIRROR) {
636:       for (j=0; j<s_x; j++) idx[nn++] = bases[rank] + x*(i + 1) - 2 - j;
637:     }
638:   }

640:   for (i=1; i<=s_y; i++) {
641:     if (n6 >= 0) { /* left above */
642:       x_t = lx[n6 % m];
643:       /* y_t = ly[(n6/m)]; */
644:       s_t = bases[n6] + (i)*x_t - s_x;
645:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
646:     }

648:     if (n7 >= 0) { /* directly above */
649:       x_t = x;
650:       /* y_t = ly[(n7/m)]; */
651:       s_t = bases[n7] + (i-1)*x_t;
652:       for (j=0; j<x_t; j++) idx[nn++] = s_t++;
653:     } else if (by == DMDA_BOUNDARY_MIRROR) {
654:       for (j=0; j<x; j++) idx[nn++] = bases[rank] + x*(y - i - 1)  + j;
655:     }

657:     if (n8 >= 0) { /* right above */
658:       x_t = lx[n8 % m];
659:       /* y_t = ly[(n8/m)]; */
660:       s_t = bases[n8] + (i-1)*x_t;
661:       for (j=0; j<s_x; j++) idx[nn++] = s_t++;
662:     }
663:   }

665:   ISCreateBlock(comm,dof,nn,idx,PETSC_COPY_VALUES,&from);
666:   VecScatterCreate(global,from,local,to,&gtol);
667:   PetscLogObjectParent(da,gtol);
668:   ISDestroy(&to);
669:   ISDestroy(&from);

671:   if (stencil_type == DMDA_STENCIL_STAR) {
672:     n0 = sn0; n2 = sn2; n6 = sn6; n8 = sn8;
673:   }

675:   if (((stencil_type == DMDA_STENCIL_STAR)  ||
676:        (bx && bx != DMDA_BOUNDARY_PERIODIC) ||
677:        (by && by != DMDA_BOUNDARY_PERIODIC))) {
678:     /*
679:         Recompute the local to global mappings, this time keeping the
680:       information about the cross corner processor numbers and any ghosted
681:       but not periodic indices.
682:     */
683:     nn    = 0;
684:     xbase = bases[rank];
685:     for (i=1; i<=s_y; i++) {
686:       if (n0 >= 0) { /* left below */
687:         x_t = lx[n0 % m];
688:         y_t = ly[(n0/m)];
689:         s_t = bases[n0] + x_t*y_t - (s_y-i)*x_t - s_x;
690:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
691:       } else if (xs-Xs > 0 && ys-Ys > 0) {
692:         for (j=0; j<s_x; j++) idx[nn++] = -1;
693:       }
694:       if (n1 >= 0) { /* directly below */
695:         x_t = x;
696:         y_t = ly[(n1/m)];
697:         s_t = bases[n1] + x_t*y_t - (s_y+1-i)*x_t;
698:         for (j=0; j<x_t; j++) idx[nn++] = s_t++;
699:       } else if (ys-Ys > 0) {
700:         if (by == DMDA_BOUNDARY_MIRROR) {
701:           for (j=0; j<x; j++) idx[nn++] = bases[rank] + x*(s_y - i + 1)  + j;
702:         } else {
703:           for (j=0; j<x; j++) idx[nn++] = -1;
704:         }
705:       }
706:       if (n2 >= 0) { /* right below */
707:         x_t = lx[n2 % m];
708:         y_t = ly[(n2/m)];
709:         s_t = bases[n2] + x_t*y_t - (s_y+1-i)*x_t;
710:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
711:       } else if (Xe-xe> 0 && ys-Ys > 0) {
712:         for (j=0; j<s_x; j++) idx[nn++] = -1;
713:       }
714:     }

716:     for (i=0; i<y; i++) {
717:       if (n3 >= 0) { /* directly left */
718:         x_t = lx[n3 % m];
719:         /* y_t = y; */
720:         s_t = bases[n3] + (i+1)*x_t - s_x;
721:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
722:       } else if (xs-Xs > 0) {
723:         if (bx == DMDA_BOUNDARY_MIRROR) {
724:           for (j=0; j<s_x; j++) idx[nn++] = bases[rank] + x*i + s_x - j;
725:         } else {
726:           for (j=0; j<s_x; j++) idx[nn++] = -1;
727:         }
728:       }

730:       for (j=0; j<x; j++) idx[nn++] = xbase++; /* interior */

732:       if (n5 >= 0) { /* directly right */
733:         x_t = lx[n5 % m];
734:         /* y_t = y; */
735:         s_t = bases[n5] + (i)*x_t;
736:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
737:       } else if (Xe-xe > 0) {
738:         if (bx == DMDA_BOUNDARY_MIRROR) {
739:           for (j=0; j<s_x; j++) idx[nn++] = bases[rank] + x*(i + 1) - 2 - j;
740:         } else {
741:           for (j=0; j<s_x; j++) idx[nn++] = -1;
742:         }
743:       }
744:     }

746:     for (i=1; i<=s_y; i++) {
747:       if (n6 >= 0) { /* left above */
748:         x_t = lx[n6 % m];
749:         /* y_t = ly[(n6/m)]; */
750:         s_t = bases[n6] + (i)*x_t - s_x;
751:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
752:       } else if (xs-Xs > 0 && Ye-ye > 0) {
753:         for (j=0; j<s_x; j++) idx[nn++] = -1;
754:       }
755:       if (n7 >= 0) { /* directly above */
756:         x_t = x;
757:         /* y_t = ly[(n7/m)]; */
758:         s_t = bases[n7] + (i-1)*x_t;
759:         for (j=0; j<x_t; j++) idx[nn++] = s_t++;
760:       } else if (Ye-ye > 0) {
761:         if (by == DMDA_BOUNDARY_MIRROR) {
762:           for (j=0; j<x; j++) idx[nn++] = bases[rank] + x*(y - i - 1)  + j;
763:         } else {
764:           for (j=0; j<x; j++) idx[nn++] = -1;
765:         }
766:       }
767:       if (n8 >= 0) { /* right above */
768:         x_t = lx[n8 % m];
769:         /* y_t = ly[(n8/m)]; */
770:         s_t = bases[n8] + (i-1)*x_t;
771:         for (j=0; j<s_x; j++) idx[nn++] = s_t++;
772:       } else if (Xe-xe > 0 && Ye-ye > 0) {
773:         for (j=0; j<s_x; j++) idx[nn++] = -1;
774:       }
775:     }
776:   }
777:   /*
778:      Set the local to global ordering in the global vector, this allows use
779:      of VecSetValuesLocal().
780:   */
781:   ISCreateBlock(comm,dof,nn,idx,PETSC_OWN_POINTER,&ltogis);
782:   PetscMalloc(nn*dof*sizeof(PetscInt),&idx_cpy);
783:   PetscLogObjectMemory(da,nn*dof*sizeof(PetscInt));
784:   ISGetIndices(ltogis, &idx_full);
785:   PetscMemcpy(idx_cpy,idx_full,nn*dof*sizeof(PetscInt));
786:   ISRestoreIndices(ltogis, &idx_full);
787:   ISLocalToGlobalMappingCreateIS(ltogis,&da->ltogmap);
788:   PetscLogObjectParent(da,da->ltogmap);
789:   ISDestroy(&ltogis);
790:   ISLocalToGlobalMappingBlock(da->ltogmap,dd->w,&da->ltogmapb);
791:   PetscLogObjectParent(da,da->ltogmap);

793:   PetscFree2(bases,ldims);
794:   dd->m = m;  dd->n  = n;
795:   /* note petsc expects xs/xe/Xs/Xe to be multiplied by #dofs in many places */
796:   dd->xs = xs*dof; dd->xe = xe*dof; dd->ys = ys; dd->ye = ye; dd->zs = 0; dd->ze = 1;
797:   dd->Xs = Xs*dof; dd->Xe = Xe*dof; dd->Ys = Ys; dd->Ye = Ye; dd->Zs = 0; dd->Ze = 1;

799:   VecDestroy(&local);
800:   VecDestroy(&global);

802:   dd->gtol      = gtol;
803:   dd->ltog      = ltog;
804:   dd->idx       = idx_cpy;
805:   dd->Nl        = nn*dof;
806:   dd->base      = base;
807:   da->ops->view = DMView_DA_2d;
808:   dd->ltol      = NULL;
809:   dd->ao        = NULL;
810:   return(0);
811: }

815: /*@C
816:    DMDACreate2d -  Creates an object that will manage the communication of  two-dimensional
817:    regular array data that is distributed across some processors.

819:    Collective on MPI_Comm

821:    Input Parameters:
822: +  comm - MPI communicator
823: .  bx,by - type of ghost nodes the array have.
824:          Use one of DMDA_BOUNDARY_NONE, DMDA_BOUNDARY_GHOSTED, DMDA_BOUNDARY_PERIODIC.
825: .  stencil_type - stencil type.  Use either DMDA_STENCIL_BOX or DMDA_STENCIL_STAR.
826: .  M,N - global dimension in each direction of the array (use -M and or -N to indicate that it may be set to a different value
827:             from the command line with -da_grid_x <M> -da_grid_y <N>)
828: .  m,n - corresponding number of processors in each dimension
829:          (or PETSC_DECIDE to have calculated)
830: .  dof - number of degrees of freedom per node
831: .  s - stencil width
832: -  lx, ly - arrays containing the number of nodes in each cell along
833:            the x and y coordinates, or NULL. If non-null, these
834:            must be of length as m and n, and the corresponding
835:            m and n cannot be PETSC_DECIDE. The sum of the lx[] entries
836:            must be M, and the sum of the ly[] entries must be N.

838:    Output Parameter:
839: .  da - the resulting distributed array object

841:    Options Database Key:
842: +  -dm_view - Calls DMView() at the conclusion of DMDACreate2d()
843: .  -da_grid_x <nx> - number of grid points in x direction, if M < 0
844: .  -da_grid_y <ny> - number of grid points in y direction, if N < 0
845: .  -da_processors_x <nx> - number of processors in x direction
846: .  -da_processors_y <ny> - number of processors in y direction
847: .  -da_refine_x <rx> - refinement ratio in x direction
848: .  -da_refine_y <ry> - refinement ratio in y direction
849: -  -da_refine <n> - refine the DMDA n times before creating, if M or N < 0


852:    Level: beginner

854:    Notes:
855:    The stencil type DMDA_STENCIL_STAR with width 1 corresponds to the
856:    standard 5-pt stencil, while DMDA_STENCIL_BOX with width 1 denotes
857:    the standard 9-pt stencil.

859:    The array data itself is NOT stored in the DMDA, it is stored in Vec objects;
860:    The appropriate vector objects can be obtained with calls to DMCreateGlobalVector()
861:    and DMCreateLocalVector() and calls to VecDuplicate() if more are needed.

863: .keywords: distributed array, create, two-dimensional

865: .seealso: DMDestroy(), DMView(), DMDACreate1d(), DMDACreate3d(), DMGlobalToLocalBegin(), DMDAGetRefinementFactor(),
866:           DMGlobalToLocalEnd(), DMLocalToGlobalBegin(), DMDALocalToLocalBegin(), DMDALocalToLocalEnd(), DMDASetRefinementFactor(),
867:           DMDAGetInfo(), DMCreateGlobalVector(), DMCreateLocalVector(), DMDACreateNaturalVector(), DMLoad(), DMDAGetOwnershipRanges()

869: @*/

871: PetscErrorCode  DMDACreate2d(MPI_Comm comm,DMDABoundaryType bx,DMDABoundaryType by,DMDAStencilType stencil_type,
872:                           PetscInt M,PetscInt N,PetscInt m,PetscInt n,PetscInt dof,PetscInt s,const PetscInt lx[],const PetscInt ly[],DM *da)
873: {

877:   DMDACreate(comm, da);
878:   DMDASetDim(*da, 2);
879:   DMDASetSizes(*da, M, N, 1);
880:   DMDASetNumProcs(*da, m, n, PETSC_DECIDE);
881:   DMDASetBoundaryType(*da, bx, by, DMDA_BOUNDARY_NONE);
882:   DMDASetDof(*da, dof);
883:   DMDASetStencilType(*da, stencil_type);
884:   DMDASetStencilWidth(*da, s);
885:   DMDASetOwnershipRanges(*da, lx, ly, NULL);
886:   /* This violates the behavior for other classes, but right now users expect negative dimensions to be handled this way */
887:   DMSetFromOptions(*da);
888:   DMSetUp(*da);
889:   DMViewFromOptions(*da,NULL,"-dm_view");
890:   return(0);
891: }