Actual source code: dacreate.c
petsc-3.11.4 2019-09-28
2: #include <petsc/private/dmdaimpl.h>
4: PetscErrorCode DMSetFromOptions_DA(PetscOptionItems *PetscOptionsObject,DM da)
5: {
7: DM_DA *dd = (DM_DA*)da->data;
8: PetscInt refine = 0,dim = da->dim,maxnlevels = 100,refx[100],refy[100],refz[100],n,i;
9: PetscBool flg;
14: if (dd->M < 0) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Dimension must be non-negative, call DMSetFromOptions() if you want to change the value at runtime");
15: if (dd->N < 0) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Dimension must be non-negative, call DMSetFromOptions() if you want to change the value at runtime");
16: if (dd->P < 0) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Dimension must be non-negative, call DMSetFromOptions() if you want to change the value at runtime");
18: PetscOptionsHead(PetscOptionsObject,"DMDA Options");
19: PetscOptionsInt("-da_grid_x","Number of grid points in x direction","DMDASetSizes",dd->M,&dd->M,NULL);
20: PetscOptionsInt("-da_grid_y","Number of grid points in y direction","DMDASetSizes",dd->N,&dd->N,NULL);
21: PetscOptionsInt("-da_grid_z","Number of grid points in z direction","DMDASetSizes",dd->P,&dd->P,NULL);
23: PetscOptionsInt("-da_overlap","Decomposition overlap in all directions","DMDASetOverlap",dd->xol,&dd->xol,&flg);
24: if (flg) {DMDASetOverlap(da,dd->xol,dd->xol,dd->xol);}
25: PetscOptionsInt("-da_overlap_x","Decomposition overlap in x direction","DMDASetOverlap",dd->xol,&dd->xol,NULL);
26: if (dim > 1) {PetscOptionsInt("-da_overlap_y","Decomposition overlap in y direction","DMDASetOverlap",dd->yol,&dd->yol,NULL);}
27: if (dim > 2) {PetscOptionsInt("-da_overlap_z","Decomposition overlap in z direction","DMDASetOverlap",dd->zol,&dd->zol,NULL);}
29: PetscOptionsInt("-da_local_subdomains","","DMDASetNumLocalSubdomains",dd->Nsub,&dd->Nsub,&flg);
30: if (flg) {DMDASetNumLocalSubDomains(da,dd->Nsub);}
32: /* Handle DMDA parallel distribution */
33: PetscOptionsInt("-da_processors_x","Number of processors in x direction","DMDASetNumProcs",dd->m,&dd->m,NULL);
34: if (dim > 1) {PetscOptionsInt("-da_processors_y","Number of processors in y direction","DMDASetNumProcs",dd->n,&dd->n,NULL);}
35: if (dim > 2) {PetscOptionsInt("-da_processors_z","Number of processors in z direction","DMDASetNumProcs",dd->p,&dd->p,NULL);}
36: /* Handle DMDA refinement */
37: PetscOptionsInt("-da_refine_x","Refinement ratio in x direction","DMDASetRefinementFactor",dd->refine_x,&dd->refine_x,NULL);
38: if (dim > 1) {PetscOptionsInt("-da_refine_y","Refinement ratio in y direction","DMDASetRefinementFactor",dd->refine_y,&dd->refine_y,NULL);}
39: if (dim > 2) {PetscOptionsInt("-da_refine_z","Refinement ratio in z direction","DMDASetRefinementFactor",dd->refine_z,&dd->refine_z,NULL);}
40: dd->coarsen_x = dd->refine_x; dd->coarsen_y = dd->refine_y; dd->coarsen_z = dd->refine_z;
42: /* Get refinement factors, defaults taken from the coarse DMDA */
43: DMDAGetRefinementFactor(da,&refx[0],&refy[0],&refz[0]);
44: for (i=1; i<maxnlevels; i++) {
45: refx[i] = refx[0];
46: refy[i] = refy[0];
47: refz[i] = refz[0];
48: }
49: n = maxnlevels;
50: PetscOptionsIntArray("-da_refine_hierarchy_x","Refinement factor for each level","None",refx,&n,&flg);
51: if (flg) {
52: dd->refine_x = refx[0];
53: dd->refine_x_hier_n = n;
54: PetscMalloc1(n,&dd->refine_x_hier);
55: PetscMemcpy(dd->refine_x_hier,refx,n*sizeof(PetscInt));
56: }
57: if (dim > 1) {
58: n = maxnlevels;
59: PetscOptionsIntArray("-da_refine_hierarchy_y","Refinement factor for each level","None",refy,&n,&flg);
60: if (flg) {
61: dd->refine_y = refy[0];
62: dd->refine_y_hier_n = n;
63: PetscMalloc1(n,&dd->refine_y_hier);
64: PetscMemcpy(dd->refine_y_hier,refy,n*sizeof(PetscInt));
65: }
66: }
67: if (dim > 2) {
68: n = maxnlevels;
69: PetscOptionsIntArray("-da_refine_hierarchy_z","Refinement factor for each level","None",refz,&n,&flg);
70: if (flg) {
71: dd->refine_z = refz[0];
72: dd->refine_z_hier_n = n;
73: PetscMalloc1(n,&dd->refine_z_hier);
74: PetscMemcpy(dd->refine_z_hier,refz,n*sizeof(PetscInt));
75: }
76: }
78: PetscOptionsInt("-da_refine","Uniformly refine DA one or more times","None",refine,&refine,NULL);
79: PetscOptionsTail();
81: while (refine--) {
82: if (dd->bx == DM_BOUNDARY_PERIODIC || dd->interptype == DMDA_Q0) {
83: dd->M = dd->refine_x*dd->M;
84: } else {
85: dd->M = 1 + dd->refine_x*(dd->M - 1);
86: }
87: if (dd->by == DM_BOUNDARY_PERIODIC || dd->interptype == DMDA_Q0) {
88: dd->N = dd->refine_y*dd->N;
89: } else {
90: dd->N = 1 + dd->refine_y*(dd->N - 1);
91: }
92: if (dd->bz == DM_BOUNDARY_PERIODIC || dd->interptype == DMDA_Q0) {
93: dd->P = dd->refine_z*dd->P;
94: } else {
95: dd->P = 1 + dd->refine_z*(dd->P - 1);
96: }
97: da->levelup++;
98: if (da->levelup - da->leveldown >= 0) {
99: dd->refine_x = refx[da->levelup - da->leveldown];
100: dd->refine_y = refy[da->levelup - da->leveldown];
101: dd->refine_z = refz[da->levelup - da->leveldown];
102: }
103: if (da->levelup - da->leveldown >= 1) {
104: dd->coarsen_x = refx[da->levelup - da->leveldown - 1];
105: dd->coarsen_y = refy[da->levelup - da->leveldown - 1];
106: dd->coarsen_z = refz[da->levelup - da->leveldown - 1];
107: }
108: }
109: return(0);
110: }
112: extern PetscErrorCode DMCreateGlobalVector_DA(DM,Vec*);
113: extern PetscErrorCode DMCreateLocalVector_DA(DM,Vec*);
114: extern PetscErrorCode DMGlobalToLocalBegin_DA(DM,Vec,InsertMode,Vec);
115: extern PetscErrorCode DMGlobalToLocalEnd_DA(DM,Vec,InsertMode,Vec);
116: extern PetscErrorCode DMLocalToGlobalBegin_DA(DM,Vec,InsertMode,Vec);
117: extern PetscErrorCode DMLocalToGlobalEnd_DA(DM,Vec,InsertMode,Vec);
118: extern PetscErrorCode DMLocalToLocalBegin_DA(DM,Vec,InsertMode,Vec);
119: extern PetscErrorCode DMLocalToLocalEnd_DA(DM,Vec,InsertMode,Vec);
120: extern PetscErrorCode DMCreateInterpolation_DA(DM,DM,Mat*,Vec*);
121: extern PetscErrorCode DMCreateColoring_DA(DM,ISColoringType,ISColoring*);
122: extern PetscErrorCode DMCreateMatrix_DA(DM,Mat*);
123: extern PetscErrorCode DMCreateCoordinateDM_DA(DM,DM*);
124: extern PetscErrorCode DMRefine_DA(DM,MPI_Comm,DM*);
125: extern PetscErrorCode DMCoarsen_DA(DM,MPI_Comm,DM*);
126: extern PetscErrorCode DMRefineHierarchy_DA(DM,PetscInt,DM[]);
127: extern PetscErrorCode DMCoarsenHierarchy_DA(DM,PetscInt,DM[]);
128: extern PetscErrorCode DMCreateInjection_DA(DM,DM,Mat*);
129: extern PetscErrorCode DMCreateAggregates_DA(DM,DM,Mat*);
130: extern PetscErrorCode DMView_DA(DM,PetscViewer);
131: extern PetscErrorCode DMSetUp_DA(DM);
132: extern PetscErrorCode DMDestroy_DA(DM);
133: extern PetscErrorCode DMCreateDomainDecomposition_DA(DM,PetscInt*,char***,IS**,IS**,DM**);
134: extern PetscErrorCode DMCreateDomainDecompositionScatters_DA(DM,PetscInt,DM*,VecScatter**,VecScatter**,VecScatter**);
135: PETSC_INTERN PetscErrorCode DMGetCompatibility_DA(DM,DM,PetscBool*,PetscBool*);
137: PetscErrorCode DMLoad_DA(DM da,PetscViewer viewer)
138: {
139: PetscErrorCode ierr;
140: PetscInt dim,m,n,p,dof,swidth;
141: DMDAStencilType stencil;
142: DMBoundaryType bx,by,bz;
143: PetscBool coors;
144: DM dac;
145: Vec c;
148: PetscViewerBinaryRead(viewer,&dim,1,NULL,PETSC_INT);
149: PetscViewerBinaryRead(viewer,&m,1,NULL,PETSC_INT);
150: PetscViewerBinaryRead(viewer,&n,1,NULL,PETSC_INT);
151: PetscViewerBinaryRead(viewer,&p,1,NULL,PETSC_INT);
152: PetscViewerBinaryRead(viewer,&dof,1,NULL,PETSC_INT);
153: PetscViewerBinaryRead(viewer,&swidth,1,NULL,PETSC_INT);
154: PetscViewerBinaryRead(viewer,&bx,1,NULL,PETSC_ENUM);
155: PetscViewerBinaryRead(viewer,&by,1,NULL,PETSC_ENUM);
156: PetscViewerBinaryRead(viewer,&bz,1,NULL,PETSC_ENUM);
157: PetscViewerBinaryRead(viewer,&stencil,1,NULL,PETSC_ENUM);
159: DMSetDimension(da, dim);
160: DMDASetSizes(da, m,n,p);
161: DMDASetBoundaryType(da, bx, by, bz);
162: DMDASetDof(da, dof);
163: DMDASetStencilType(da, stencil);
164: DMDASetStencilWidth(da, swidth);
165: DMSetUp(da);
166: PetscViewerBinaryRead(viewer,&coors,1,NULL,PETSC_ENUM);
167: if (coors) {
168: DMGetCoordinateDM(da,&dac);
169: DMCreateGlobalVector(dac,&c);
170: VecLoad(c,viewer);
171: DMSetCoordinates(da,c);
172: VecDestroy(&c);
173: }
174: return(0);
175: }
177: PetscErrorCode DMCreateSubDM_DA(DM dm, PetscInt numFields, const PetscInt fields[], IS *is, DM *subdm)
178: {
179: DM_DA *da = (DM_DA*) dm->data;
180: PetscSection section;
184: if (subdm) {
185: PetscSF sf;
186: Vec coords;
187: void *ctx;
188: /* Cannot use DMClone since the dof stuff is mixed in. Ugh
189: DMClone(dm, subdm); */
190: DMCreate(PetscObjectComm((PetscObject)dm), subdm);
191: DMGetPointSF(dm, &sf);
192: DMSetPointSF(*subdm, sf);
193: DMGetApplicationContext(dm, &ctx);
194: DMSetApplicationContext(*subdm, ctx);
195: DMGetCoordinatesLocal(dm, &coords);
196: if (coords) {
197: DMSetCoordinatesLocal(*subdm, coords);
198: } else {
199: DMGetCoordinates(dm, &coords);
200: if (coords) {DMSetCoordinates(*subdm, coords);}
201: }
203: DMSetType(*subdm, DMDA);
204: DMSetDimension(*subdm, dm->dim);
205: DMDASetSizes(*subdm, da->M, da->N, da->P);
206: DMDASetNumProcs(*subdm, da->m, da->n, da->p);
207: DMDASetBoundaryType(*subdm, da->bx, da->by, da->bz);
208: DMDASetDof(*subdm, numFields);
209: DMDASetStencilType(*subdm, da->stencil_type);
210: DMDASetStencilWidth(*subdm, da->s);
211: DMDASetOwnershipRanges(*subdm, da->lx, da->ly, da->lz);
212: }
213: DMGetSection(dm, §ion);
214: if (section) {
215: DMCreateSectionSubDM(dm, numFields, fields, is, subdm);
216: } else {
217: if (is) {
218: PetscInt *indices, cnt = 0, dof = da->w, i, j;
220: PetscMalloc1(da->Nlocal*numFields/dof, &indices);
221: for (i = da->base/dof; i < (da->base+da->Nlocal)/dof; ++i) {
222: for (j = 0; j < numFields; ++j) {
223: indices[cnt++] = dof*i + fields[j];
224: }
225: }
226: if (cnt != da->Nlocal*numFields/dof) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Count %d does not equal expected value %d", cnt, da->Nlocal*numFields/dof);
227: ISCreateGeneral(PetscObjectComm((PetscObject) dm), cnt, indices, PETSC_OWN_POINTER, is);
228: }
229: }
230: return(0);
231: }
233: PetscErrorCode DMCreateFieldDecomposition_DA(DM dm, PetscInt *len,char ***namelist, IS **islist, DM **dmlist)
234: {
235: PetscInt i;
237: DM_DA *dd = (DM_DA*)dm->data;
238: PetscInt dof = dd->w;
241: if (len) *len = dof;
242: if (islist) {
243: Vec v;
244: PetscInt rstart,n;
246: DMGetGlobalVector(dm,&v);
247: VecGetOwnershipRange(v,&rstart,NULL);
248: VecGetLocalSize(v,&n);
249: DMRestoreGlobalVector(dm,&v);
250: PetscMalloc1(dof,islist);
251: for (i=0; i<dof; i++) {
252: ISCreateStride(PetscObjectComm((PetscObject)dm),n/dof,rstart+i,dof,&(*islist)[i]);
253: }
254: }
255: if (namelist) {
256: PetscMalloc1(dof, namelist);
257: if (dd->fieldname) {
258: for (i=0; i<dof; i++) {
259: PetscStrallocpy(dd->fieldname[i],&(*namelist)[i]);
260: }
261: } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Currently DMDA must have fieldnames");
262: }
263: if (dmlist) {
264: DM da;
266: DMDACreate(PetscObjectComm((PetscObject)dm), &da);
267: DMSetDimension(da, dm->dim);
268: DMDASetSizes(da, dd->M, dd->N, dd->P);
269: DMDASetNumProcs(da, dd->m, dd->n, dd->p);
270: DMDASetBoundaryType(da, dd->bx, dd->by, dd->bz);
271: DMDASetDof(da, 1);
272: DMDASetStencilType(da, dd->stencil_type);
273: DMDASetStencilWidth(da, dd->s);
274: DMSetUp(da);
275: PetscMalloc1(dof,dmlist);
276: for (i=0; i<dof-1; i++) {PetscObjectReference((PetscObject)da);}
277: for (i=0; i<dof; i++) (*dmlist)[i] = da;
278: }
279: return(0);
280: }
282: PetscErrorCode DMClone_DA(DM dm, DM *newdm)
283: {
284: DM_DA *da = (DM_DA *) dm->data;
288: DMSetType(*newdm, DMDA);
289: DMSetDimension(*newdm, dm->dim);
290: DMDASetSizes(*newdm, da->M, da->N, da->P);
291: DMDASetNumProcs(*newdm, da->m, da->n, da->p);
292: DMDASetBoundaryType(*newdm, da->bx, da->by, da->bz);
293: DMDASetDof(*newdm, da->w);
294: DMDASetStencilType(*newdm, da->stencil_type);
295: DMDASetStencilWidth(*newdm, da->s);
296: DMDASetOwnershipRanges(*newdm, da->lx, da->ly, da->lz);
297: DMSetUp(*newdm);
298: return(0);
299: }
301: static PetscErrorCode DMHasCreateInjection_DA(DM dm, PetscBool *flg)
302: {
303: DM_DA *da = (DM_DA *)dm->data;
308: *flg = da->interptype == DMDA_Q1 ? PETSC_TRUE : PETSC_FALSE;
309: return(0);
310: }
312: static PetscErrorCode DMGetDimPoints_DA(DM dm, PetscInt dim, PetscInt *pStart, PetscInt *pEnd)
313: {
317: DMDAGetDepthStratum(dm, dim, pStart, pEnd);
318: return(0);
319: }
321: static PetscErrorCode DMGetNeighbors_DA(DM dm, PetscInt *nranks, const PetscMPIInt *ranks[])
322: {
324: PetscInt dim;
325: DMDAStencilType st;
326:
328: DMDAGetNeighbors(dm,ranks);
329: DMDAGetInfo(dm,&dim,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,&st);
331: switch (dim) {
332: case 1:
333: *nranks = 3;
334: /* if (st == DMDA_STENCIL_STAR) { *nranks = 3; } */
335: break;
336: case 2:
337: *nranks = 9;
338: /* if (st == DMDA_STENCIL_STAR) { *nranks = 5; } */
339: break;
340: case 3:
341: *nranks = 27;
342: /* if (st == DMDA_STENCIL_STAR) { *nranks = 7; } */
343: break;
344: default:
345: break;
346: }
347: return(0);
348: }
350: /*MC
351: DMDA = "da" - A DM object that is used to manage data for a structured grid in 1, 2, or 3 dimensions.
352: In the global representation of the vector each process stores a non-overlapping rectangular (or slab in 3d) portion of the grid points.
353: In the local representation these rectangular regions (slabs) are extended in all directions by a stencil width.
355: The vectors can be thought of as either cell centered or vertex centered on the mesh. But some variables cannot be cell centered and others
356: vertex centered.
358: Level: intermediate
360: .seealso: DMType, DMCOMPOSITE, DMDACreate(), DMCreate(), DMSetType()
361: M*/
363: extern PetscErrorCode DMProjectFunctionLocal_DA(DM, PetscReal, PetscErrorCode (**)(PetscInt, PetscReal, const PetscReal [], PetscInt, PetscScalar *, void *), void **, InsertMode, Vec);
364: extern PetscErrorCode DMComputeL2Diff_DA(DM, PetscReal, PetscErrorCode (**)(PetscInt, PetscReal, const PetscReal [], PetscInt, PetscScalar *, void *), void **, Vec, PetscReal *);
365: extern PetscErrorCode DMComputeL2GradientDiff_DA(DM, PetscReal, PetscErrorCode (**)(PetscInt, PetscReal, const PetscReal [], const PetscReal [],PetscInt, PetscScalar *, void *), void **, Vec,const PetscReal [], PetscReal *);
366: extern PetscErrorCode DMLocatePoints_DA_Regular(DM,Vec,DMPointLocationType,PetscSF);
367: PETSC_INTERN PetscErrorCode DMSetUpGLVisViewer_DMDA(PetscObject,PetscViewer);
369: PETSC_EXTERN PetscErrorCode DMCreate_DA(DM da)
370: {
372: DM_DA *dd;
376: PetscNewLog(da,&dd);
377: da->data = dd;
379: da->dim = -1;
380: dd->interptype = DMDA_Q1;
381: dd->refine_x = 2;
382: dd->refine_y = 2;
383: dd->refine_z = 2;
384: dd->coarsen_x = 2;
385: dd->coarsen_y = 2;
386: dd->coarsen_z = 2;
387: dd->fieldname = NULL;
388: dd->nlocal = -1;
389: dd->Nlocal = -1;
390: dd->M = -1;
391: dd->N = -1;
392: dd->P = -1;
393: dd->m = -1;
394: dd->n = -1;
395: dd->p = -1;
396: dd->w = -1;
397: dd->s = -1;
399: dd->xs = -1; dd->xe = -1; dd->ys = -1; dd->ye = -1; dd->zs = -1; dd->ze = -1;
400: dd->Xs = -1; dd->Xe = -1; dd->Ys = -1; dd->Ye = -1; dd->Zs = -1; dd->Ze = -1;
402: dd->Nsub = 1;
403: dd->xol = 0;
404: dd->yol = 0;
405: dd->zol = 0;
406: dd->xo = 0;
407: dd->yo = 0;
408: dd->zo = 0;
409: dd->Mo = -1;
410: dd->No = -1;
411: dd->Po = -1;
413: dd->gtol = NULL;
414: dd->ltol = NULL;
415: dd->ao = NULL;
416: PetscStrallocpy(AOBASIC,(char**)&dd->aotype);
417: dd->base = -1;
418: dd->bx = DM_BOUNDARY_NONE;
419: dd->by = DM_BOUNDARY_NONE;
420: dd->bz = DM_BOUNDARY_NONE;
421: dd->stencil_type = DMDA_STENCIL_BOX;
422: dd->interptype = DMDA_Q1;
423: dd->lx = NULL;
424: dd->ly = NULL;
425: dd->lz = NULL;
427: dd->elementtype = DMDA_ELEMENT_Q1;
429: da->ops->globaltolocalbegin = DMGlobalToLocalBegin_DA;
430: da->ops->globaltolocalend = DMGlobalToLocalEnd_DA;
431: da->ops->localtoglobalbegin = DMLocalToGlobalBegin_DA;
432: da->ops->localtoglobalend = DMLocalToGlobalEnd_DA;
433: da->ops->localtolocalbegin = DMLocalToLocalBegin_DA;
434: da->ops->localtolocalend = DMLocalToLocalEnd_DA;
435: da->ops->createglobalvector = DMCreateGlobalVector_DA;
436: da->ops->createlocalvector = DMCreateLocalVector_DA;
437: da->ops->createinterpolation = DMCreateInterpolation_DA;
438: da->ops->getcoloring = DMCreateColoring_DA;
439: da->ops->creatematrix = DMCreateMatrix_DA;
440: da->ops->refine = DMRefine_DA;
441: da->ops->coarsen = DMCoarsen_DA;
442: da->ops->refinehierarchy = DMRefineHierarchy_DA;
443: da->ops->coarsenhierarchy = DMCoarsenHierarchy_DA;
444: da->ops->getinjection = DMCreateInjection_DA;
445: da->ops->hascreateinjection = DMHasCreateInjection_DA;
446: da->ops->getaggregates = DMCreateAggregates_DA;
447: da->ops->destroy = DMDestroy_DA;
448: da->ops->view = 0;
449: da->ops->setfromoptions = DMSetFromOptions_DA;
450: da->ops->setup = DMSetUp_DA;
451: da->ops->clone = DMClone_DA;
452: da->ops->load = DMLoad_DA;
453: da->ops->createcoordinatedm = DMCreateCoordinateDM_DA;
454: da->ops->createsubdm = DMCreateSubDM_DA;
455: da->ops->createfielddecomposition = DMCreateFieldDecomposition_DA;
456: da->ops->createdomaindecomposition = DMCreateDomainDecomposition_DA;
457: da->ops->createddscatters = DMCreateDomainDecompositionScatters_DA;
458: da->ops->getdimpoints = DMGetDimPoints_DA;
459: da->ops->projectfunctionlocal = DMProjectFunctionLocal_DA;
460: da->ops->computel2diff = DMComputeL2Diff_DA;
461: da->ops->computel2gradientdiff = DMComputeL2GradientDiff_DA;
462: da->ops->getneighbors = DMGetNeighbors_DA;
463: da->ops->locatepoints = DMLocatePoints_DA_Regular;
464: da->ops->getcompatibility = DMGetCompatibility_DA;
465: PetscObjectComposeFunction((PetscObject)da,"DMSetUpGLVisViewer_C",DMSetUpGLVisViewer_DMDA);
466: return(0);
467: }
469: /*@
470: DMDACreate - Creates a DMDA object.
472: Collective on MPI_Comm
474: Input Parameter:
475: . comm - The communicator for the DMDA object
477: Output Parameter:
478: . da - The DMDA object
480: Level: advanced
482: Developers Note: Since there exists DMDACreate1/2/3d() should this routine even exist?
484: .keywords: DMDA, create
485: .seealso: DMDASetSizes(), DMDADuplicate(), DMDACreate1d(), DMDACreate2d(), DMDACreate3d()
486: @*/
487: PetscErrorCode DMDACreate(MPI_Comm comm, DM *da)
488: {
493: DMCreate(comm,da);
494: DMSetType(*da,DMDA);
495: return(0);
496: }