Actual source code: stag1d.c
petsc-3.11.4 2019-09-28
1: /*
2: Functions specific to the 1-dimensional implementation of DMStag
3: */
4: #include <petsc/private/dmstagimpl.h>
6: /*@C
7: DMStagCreate1d - Create an object to manage data living on the faces, edges, and vertices of a parallelized regular 1D grid.
9: Collective
11: Input Parameters:
12: + comm - MPI communicator
13: . bndx - boundary type: DM_BOUNDARY_NONE, DM_BOUNDARY_PERIODIC, or DM_BOUNDARY_GHOSTED
14: . M - global number of grid points
15: . dof0 - number of degrees of freedom per vertex/point/node/0-cell
16: . dof1 - number of degrees of freedom per element/edge/1-cell
17: . stencilType - ghost/halo region type: DMSTAG_STENCIL_BOX or DMSTAG_STENCIL_NONE
18: . stencilWidth - width, in elements, of halo/ghost region
19: - lx - array of local sizes, of length equal to the comm size, summing to M
21: Output Parameter:
22: . dm - the new DMStag object
24: Options Database Keys:
25: + -dm_view - calls DMViewFromOptions() a the conclusion of DMSetUp()
26: . -stag_grid_x <nx> - number of elements in the x direction
27: . -stag_ghost_stencil_width - width of ghost region, in elements
28: - -stag_boundary_type_x <none,ghosted,periodic> - DMBoundaryType value
30: Notes:
31: You must call DMSetUp() after this call before using the DM.
32: If you wish to use the options database (see the keys above) to change values in the DMStag, you must call
33: DMSetFromOptions() after this function but before DMSetUp().
35: Level: beginner
37: .seealso: DMSTAG, DMStagCreate2d(), DMStagCreate3d(), DMDestroy(), DMView(), DMCreateGlobalVector(), DMCreateLocalVector(), DMLocalToGlobalBegin()
38: @*/
39: PETSC_EXTERN PetscErrorCode DMStagCreate1d(MPI_Comm comm,DMBoundaryType bndx,PetscInt M,PetscInt dof0,PetscInt dof1,DMStagStencilType stencilType,PetscInt stencilWidth,const PetscInt lx[],DM* dm)
40: {
42: DM_Stag *stag;
43: PetscMPIInt size;
46: MPI_Comm_size(comm,&size);
47: DMCreate(comm,dm);
48: DMSetDimension(*dm,1); /* Must precede DMSetType */
49: DMSetType(*dm,DMSTAG);
50: stag = (DM_Stag*)(*dm)->data;
52: /* Global sizes and flags (derived quantities set in DMSetUp_Stag) */
53: stag->boundaryType[0] = bndx;
54: stag->N[0] = M;
55: stag->nRanks[0] = size;
56: stag->stencilType = stencilType;
57: stag->stencilWidth = stencilWidth;
58: DMStagSetDOF(*dm,dof0,dof1,0,0);
59: DMStagSetOwnershipRanges(*dm,lx,NULL,NULL);
61: return(0);
62: }
64: PETSC_INTERN PetscErrorCode DMStagSetUniformCoordinatesExplicit_1d(DM dm,PetscReal xmin,PetscReal xmax)
65: {
67: DM_Stag *stagCoord;
68: DM dmCoord;
69: Vec coordLocal,coord;
70: PetscReal h,min;
71: PetscScalar **arr;
72: PetscInt ind,start,n,nExtra,s;
73: PetscInt ileft,ielement;
76: DMGetCoordinateDM(dm, &dmCoord);
77: stagCoord = (DM_Stag*) dmCoord->data;
78: for (s=0; s<2; ++s) {
79: if (stagCoord->dof[s] !=0 && stagCoord->dof[s] != 1) SETERRQ2(PetscObjectComm((PetscObject)dm),PETSC_ERR_PLIB,"Coordinate DM in 1 dimensions must have 0 or 1 dof on each stratum, but stratum %d has %d dof",s,stagCoord->dof[s]);
80: }
81: DMGetLocalVector(dmCoord,&coordLocal);
83: DMStagVecGetArrayDOF(dmCoord,coordLocal,&arr);
84: if (stagCoord->dof[0]) {
85: DMStagGetLocationSlot(dmCoord,DMSTAG_LEFT,0,&ileft);
86: }
87: if (stagCoord->dof[1]) {
88: DMStagGetLocationSlot(dmCoord,DMSTAG_ELEMENT,0,&ielement);
89: }
90: DMStagGetCorners(dmCoord,&start,NULL,NULL,&n,NULL,NULL,&nExtra,NULL,NULL);
92: min = xmin;
93: h = (xmax-xmin)/stagCoord->N[0];
95: for(ind=start; ind<start + n + nExtra; ++ind) {
96: if (stagCoord->dof[0]) {
97: const PetscReal off = 0.0;
98: arr[ind][ileft] = min + ((PetscReal)ind + off) * h;
99: }
100: if (stagCoord->dof[1]) {
101: const PetscReal off = 0.5;
102: arr[ind][ielement] = min + ((PetscReal)ind + off) * h;
103: }
104: }
105: DMStagVecRestoreArrayDOF(dmCoord,coordLocal,&arr);
106: DMCreateGlobalVector(dmCoord,&coord);
107: DMLocalToGlobalBegin(dmCoord,coordLocal,INSERT_VALUES,coord);
108: DMLocalToGlobalEnd(dmCoord,coordLocal,INSERT_VALUES,coord);
109: DMSetCoordinates(dm,coord);
110: PetscLogObjectParent((PetscObject)dm,(PetscObject)coord);
111: VecDestroy(&coord);
112: DMRestoreLocalVector(dmCoord,&coordLocal);
113: return(0);
114: }
116: /* Helper functions used in DMSetUp_Stag() */
117: static PetscErrorCode DMStagComputeLocationOffsets_1d(DM);
119: PETSC_INTERN PetscErrorCode DMSetUp_Stag_1d(DM dm)
120: {
121: PetscErrorCode ierr;
122: DM_Stag * const stag = (DM_Stag*)dm->data;
123: PetscMPIInt size,rank;
124: MPI_Comm comm;
125: PetscInt j;
128: PetscObjectGetComm((PetscObject)dm,&comm);
129: MPI_Comm_size(comm,&size);
130: MPI_Comm_rank(comm,&rank);
132: /* Check Global size */
133: if (stag->N[0] < 1) SETERRQ1(comm,PETSC_ERR_ARG_OUTOFRANGE,"Global grid size of %D < 1 specified",stag->N[0]);
135: /* Local sizes */
136: if (stag->N[0] < size) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"More ranks (%d) than elements (%D) specified",size,stag->N[0]);
137: if (!stag->l[0]) {
138: /* Divide equally, giving an extra elements to higher ranks */
139: PetscMalloc1(stag->nRanks[0],&stag->l[0]);
140: for (j=0; j<stag->nRanks[0]; ++j) stag->l[0][j] = stag->N[0]/stag->nRanks[0] + (stag->N[0] % stag->nRanks[0] > j ? 1 : 0);
141: }
142: {
143: PetscInt Nchk = 0;
144: for (j=0; j<size; ++j) Nchk += stag->l[0][j];
145: if (Nchk != stag->N[0]) SETERRQ2(comm,PETSC_ERR_ARG_OUTOFRANGE,"Sum of specified local sizes (%D) is not equal to global size (%D)",Nchk,stag->N[0]);
146: }
147: stag->n[0] = stag->l[0][rank];
149: /* Rank (trivial in 1d) */
150: stag->rank[0] = rank;
151: stag->firstRank[0] = (PetscBool)(rank == 0);
152: stag->lastRank[0] = (PetscBool)(rank == size-1);
154: /* Local (unghosted) numbers of entries */
155: stag->entriesPerElement = stag->dof[0] + stag->dof[1];
156: switch (stag->boundaryType[0]) {
157: case DM_BOUNDARY_NONE:
158: case DM_BOUNDARY_GHOSTED: stag->entries = stag->n[0] * stag->entriesPerElement + (stag->lastRank[0] ? stag->dof[0] : 0); break;
159: case DM_BOUNDARY_PERIODIC: stag->entries = stag->n[0] * stag->entriesPerElement; break;
160: default: SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
161: }
163: /* Starting element */
164: stag->start[0] = 0;
165: for(j=0; j<stag->rank[0]; ++j) stag->start[0] += stag->l[0][j];
167: /* Local/ghosted size and starting element */
168: switch (stag->boundaryType[0]) {
169: case DM_BOUNDARY_NONE :
170: switch (stag->stencilType) {
171: case DMSTAG_STENCIL_NONE : /* Only dummy cells on the right */
172: stag->startGhost[0] = stag->start[0];
173: stag->nGhost[0] = stag->n[0] + (stag->lastRank[0] ? 1 : 0);
174: break;
175: case DMSTAG_STENCIL_STAR :
176: case DMSTAG_STENCIL_BOX :
177: stag->startGhost[0] = stag->firstRank[0] ? stag->start[0]: stag->start[0] - stag->stencilWidth;
178: stag->nGhost[0] = stag->n[0];
179: stag->nGhost[0] += stag->firstRank[0] ? 0 : stag->stencilWidth;
180: stag->nGhost[0] += stag->lastRank[0] ? 1 : stag->stencilWidth;
181: break;
182: default :
183: SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unrecognized ghost stencil type %d",stag->stencilType);
184: }
185: break;
186: case DM_BOUNDARY_GHOSTED:
187: case DM_BOUNDARY_PERIODIC:
188: switch (stag->stencilType) {
189: case DMSTAG_STENCIL_NONE :
190: stag->startGhost[0] = stag->start[0];
191: stag->nGhost[0] = stag->n[0];
192: break;
193: case DMSTAG_STENCIL_STAR :
194: case DMSTAG_STENCIL_BOX :
195: stag->startGhost[0] = stag->start[0] - stag->stencilWidth; /* Note that this value may be negative */
196: stag->nGhost[0] = stag->n[0] + 2*stag->stencilWidth;
197: break;
198: default :
199: SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unrecognized ghost stencil type %d",stag->stencilType);
200: }
201: break;
202: default :
203: SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
204: }
206: /* Total size of ghosted/local represention */
207: stag->entriesGhost = stag->nGhost[0]*stag->entriesPerElement;
209: /* Define neighbors */
210: PetscMalloc1(3,&stag->neighbors);
211: if (stag->firstRank[0]) {
212: switch (stag->boundaryType[0]) {
213: case DM_BOUNDARY_GHOSTED:
214: case DM_BOUNDARY_NONE: stag->neighbors[0] = -1; break;
215: case DM_BOUNDARY_PERIODIC: stag->neighbors[0] = stag->nRanks[0]-1; break;
216: default : SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
217: }
218: } else {
219: stag->neighbors[0] = stag->rank[0]-1;
220: }
221: stag->neighbors[1] = stag->rank[0];
222: if (stag->lastRank[0]) {
223: switch (stag->boundaryType[0]) {
224: case DM_BOUNDARY_GHOSTED:
225: case DM_BOUNDARY_NONE: stag->neighbors[2] = -1; break;
226: case DM_BOUNDARY_PERIODIC: stag->neighbors[2] = 0; break;
227: default : SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
228: }
229: } else {
230: stag->neighbors[2] = stag->rank[0]+1;
231: }
233: if (stag->n[0] < stag->stencilWidth) {
234: SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_SUP,"DMStag 1d setup does not support local sizes (%d) smaller than the elementwise stencil width (%d)",stag->n[0],stag->stencilWidth);
235: }
237: /* Create global->local VecScatter and ISLocalToGlobalMapping */
238: {
239: PetscInt *idxLocal,*idxGlobal,*idxGlobalAll;
240: PetscInt i,iLocal,d,entriesToTransferTotal,ghostOffsetStart,ghostOffsetEnd,nNonDummyGhost;
241: IS isLocal,isGlobal;
243: /* The offset on the right (may not be equal to the stencil width, as we
244: always have at least one ghost element, to account for the boundary
245: point, and may with ghosted boundaries), and the number of non-dummy ghost elements */
246: ghostOffsetStart = stag->start[0] - stag->startGhost[0];
247: ghostOffsetEnd = stag->startGhost[0]+stag->nGhost[0] - (stag->start[0]+stag->n[0]);
248: nNonDummyGhost = stag->nGhost[0] - (stag->lastRank[0] ? ghostOffsetEnd : 0) - (stag->firstRank[0] ? ghostOffsetStart : 0);
250: /* Compute the number of non-dummy entries in the local representation
251: This is equal to the number of non-dummy elements in the local (ghosted) representation,
252: plus some extra entries on the right boundary on the last rank*/
253: switch (stag->boundaryType[0]) {
254: case DM_BOUNDARY_GHOSTED:
255: case DM_BOUNDARY_NONE:
256: entriesToTransferTotal = nNonDummyGhost * stag->entriesPerElement + (stag->lastRank[0] ? stag->dof[0] : 0);
257: break;
258: case DM_BOUNDARY_PERIODIC:
259: entriesToTransferTotal = stag->entriesGhost; /* No dummy points */
260: break;
261: default :
262: SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
263: }
265: PetscMalloc1(entriesToTransferTotal,&idxLocal);
266: PetscMalloc1(entriesToTransferTotal,&idxGlobal);
267: PetscMalloc1(stag->entriesGhost,&idxGlobalAll);
268: if (stag->boundaryType[0] == DM_BOUNDARY_NONE) {
269: PetscInt count = 0,countAll = 0;
270: /* Left ghost points and native points */
271: for (i=stag->startGhost[0], iLocal=0; iLocal<nNonDummyGhost; ++i,++iLocal) {
272: for (d=0; d<stag->entriesPerElement; ++d,++count,++countAll) {
273: idxLocal [count] = iLocal * stag->entriesPerElement + d;
274: idxGlobal[count] = i * stag->entriesPerElement + d;
275: idxGlobalAll[countAll] = i * stag->entriesPerElement + d;
276: }
277: }
278: /* Ghost points on the right
279: Special case for last (partial dummy) element on the last rank */
280: if (stag->lastRank[0] ) {
281: i = stag->N[0];
282: iLocal = (stag->nGhost[0]-ghostOffsetEnd);
283: /* Only vertex (0-cell) dofs in global representation */
284: for (d=0; d<stag->dof[0]; ++d,++count,++countAll) {
285: idxGlobal[count] = i * stag->entriesPerElement + d;
286: idxLocal [count] = iLocal * stag->entriesPerElement + d;
287: idxGlobalAll[countAll] = i * stag->entriesPerElement + d;
288: }
289: for (d=stag->dof[0]; d<stag->entriesPerElement; ++d,++countAll) { /* Additional dummy entries */
290: idxGlobalAll[countAll] = -1;
291: }
292: }
293: } else if (stag->boundaryType[0] == DM_BOUNDARY_PERIODIC) {
294: PetscInt count = 0,iLocal = 0; /* No dummy points, so idxGlobal and idxGlobalAll are identical */
295: const PetscInt iMin = stag->firstRank[0] ? stag->start[0] : stag->startGhost[0];
296: const PetscInt iMax = stag->lastRank[0] ? stag->startGhost[0] + stag->nGhost[0] - stag->stencilWidth : stag->startGhost[0] + stag->nGhost[0];
297: /* Ghost points on the left */
298: if (stag->firstRank[0]) {
299: for (i=stag->N[0]-stag->stencilWidth; iLocal<stag->stencilWidth; ++i,++iLocal) {
300: for (d=0; d<stag->entriesPerElement; ++d,++count) {
301: idxGlobal[count] = i * stag->entriesPerElement + d;
302: idxLocal [count] = iLocal * stag->entriesPerElement + d;
303: idxGlobalAll[count] = idxGlobal[count];
304: }
305: }
306: }
307: /* Native points */
308: for (i=iMin; i<iMax; ++i,++iLocal) {
309: for (d=0; d<stag->entriesPerElement; ++d,++count) {
310: idxGlobal[count] = i * stag->entriesPerElement + d;
311: idxLocal [count] = iLocal * stag->entriesPerElement + d;
312: idxGlobalAll[count] = idxGlobal[count];
313: }
314: }
315: /* Ghost points on the right */
316: if (stag->lastRank[0]) {
317: for (i=0; iLocal<stag->nGhost[0]; ++i,++iLocal) {
318: for (d=0; d<stag->entriesPerElement; ++d,++count) {
319: idxGlobal[count] = i * stag->entriesPerElement + d;
320: idxLocal [count] = iLocal * stag->entriesPerElement + d;
321: idxGlobalAll[count] = idxGlobal[count];
322: }
323: }
324: }
325: } else if (stag->boundaryType[0] == DM_BOUNDARY_GHOSTED) {
326: PetscInt count = 0,countAll = 0;
327: /* Dummy elements on the left, on the first rank */
328: if (stag->firstRank[0]) {
329: for(iLocal=0; iLocal<ghostOffsetStart; ++iLocal) {
330: /* Complete elements full of dummy entries */
331: for (d=0; d<stag->entriesPerElement; ++d,++countAll) {
332: idxGlobalAll[countAll] = -1;
333: }
334: }
335: i = 0; /* nonDummy entries start with global entry 0 */
336: } else {
337: /* nonDummy entries start as usual */
338: i = stag->startGhost[0];
339: iLocal = 0;
340: }
342: /* non-Dummy entries */
343: {
344: PetscInt iLocalNonDummyMax = stag->firstRank[0] ? nNonDummyGhost + ghostOffsetStart : nNonDummyGhost;
345: for (; iLocal<iLocalNonDummyMax; ++i,++iLocal) {
346: for (d=0; d<stag->entriesPerElement; ++d,++count,++countAll) {
347: idxLocal [count] = iLocal * stag->entriesPerElement + d;
348: idxGlobal[count] = i * stag->entriesPerElement + d;
349: idxGlobalAll[countAll] = i * stag->entriesPerElement + d;
350: }
351: }
352: }
354: /* (partial) dummy elements on the right, on the last rank */
355: if (stag->lastRank[0]) {
356: /* First one is partial dummy */
357: i = stag->N[0];
358: iLocal = (stag->nGhost[0]-ghostOffsetEnd);
359: for (d=0; d<stag->dof[0]; ++d,++count,++countAll) { /* Only vertex (0-cell) dofs in global representation */
360: idxLocal [count] = iLocal * stag->entriesPerElement + d;
361: idxGlobal[count] = i * stag->entriesPerElement + d;
362: idxGlobalAll[countAll] = i * stag->entriesPerElement + d;
363: }
364: for (d=stag->dof[0]; d<stag->entriesPerElement; ++d,++countAll) { /* Additional dummy entries */
365: idxGlobalAll[countAll] = -1;
366: }
367: for (iLocal = stag->nGhost[0] - ghostOffsetEnd + 1; iLocal < stag->nGhost[0]; ++iLocal) {
368: /* Additional dummy elements */
369: for (d=0; d<stag->entriesPerElement; ++d,++countAll) {
370: idxGlobalAll[countAll] = -1;
371: }
372: }
373: }
374: } else SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Unsupported x boundary type %s",DMBoundaryTypes[stag->boundaryType[0]]);
376: /* Create Local IS (transferring pointer ownership) */
377: ISCreateGeneral(PetscObjectComm((PetscObject)dm),entriesToTransferTotal,idxLocal,PETSC_OWN_POINTER,&isLocal);
379: /* Create Global IS (transferring pointer ownership) */
380: ISCreateGeneral(PetscObjectComm((PetscObject)dm),entriesToTransferTotal,idxGlobal,PETSC_OWN_POINTER,&isGlobal);
382: /* Create stag->gtol, which doesn't include dummy entries */
383: {
384: Vec local,global;
385: VecCreateMPIWithArray(PetscObjectComm((PetscObject)dm),1,stag->entries,PETSC_DECIDE,NULL,&global);
386: VecCreateSeqWithArray(PETSC_COMM_SELF,stag->entriesPerElement,stag->entriesGhost,NULL,&local);
387: VecScatterCreate(global,isGlobal,local,isLocal,&stag->gtol);
388: VecDestroy(&global);
389: VecDestroy(&local);
390: }
392: /* Destroy ISs */
393: ISDestroy(&isLocal);
394: ISDestroy(&isGlobal);
396: /* Create local-to-global map (transferring pointer ownership) */
397: ISLocalToGlobalMappingCreate(comm,1,stag->entriesGhost,idxGlobalAll,PETSC_OWN_POINTER,&dm->ltogmap);
398: PetscLogObjectParent((PetscObject)dm,(PetscObject)dm->ltogmap);
399: }
401: /* Precompute location offsets */
402: DMStagComputeLocationOffsets_1d(dm);
404: /* View from Options */
405: DMViewFromOptions(dm,NULL,"-dm_view");
407: return(0);
408: }
410: static PetscErrorCode DMStagComputeLocationOffsets_1d(DM dm)
411: {
412: PetscErrorCode ierr;
413: DM_Stag * const stag = (DM_Stag*)dm->data;
414: const PetscInt epe = stag->entriesPerElement;
417: PetscMalloc1(DMSTAG_NUMBER_LOCATIONS,&stag->locationOffsets);
418: stag->locationOffsets[DMSTAG_LEFT] = 0;
419: stag->locationOffsets[DMSTAG_ELEMENT] = stag->locationOffsets[DMSTAG_LEFT] + stag->dof[0];
420: stag->locationOffsets[DMSTAG_RIGHT] = stag->locationOffsets[DMSTAG_LEFT] + epe;
421: return(0);
422: }