Actual source code: dagetelem.c

petsc-master 2020-11-28
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  2: #include <petsc/private/dmdaimpl.h>

  4: static PetscErrorCode DMDAGetElements_1D(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
  5: {
  7:   DM_DA          *da = (DM_DA*)dm->data;
  8:   PetscInt       i,xs,xe,Xs,Xe;
  9:   PetscInt       cnt=0;

 12:   if (!da->e) {
 13:     PetscInt corners[2];

 15:     if (!da->s) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Cannot get elements for DMDA with zero stencil width");
 16:     DMDAGetCorners(dm,&xs,NULL,NULL,&xe,NULL,NULL);
 17:     DMDAGetGhostCorners(dm,&Xs,NULL,NULL,&Xe,NULL,NULL);
 18:     xe    += xs; Xe += Xs; if (xs != Xs) xs -= 1;
 19:     da->ne = 1*(xe - xs - 1);
 20:     PetscMalloc1(1 + 2*da->ne,&da->e);
 21:     for (i=xs; i<xe-1; i++) {
 22:       da->e[cnt++] = (i-Xs);
 23:       da->e[cnt++] = (i-Xs+1);
 24:     }
 25:     da->nen = 2;

 27:     corners[0] = (xs  -Xs);
 28:     corners[1] = (xe-1-Xs);
 29:     ISCreateGeneral(PETSC_COMM_SELF,2,corners,PETSC_COPY_VALUES,&da->ecorners);
 30:   }
 31:   *nel = da->ne;
 32:   *nen = da->nen;
 33:   *e   = da->e;
 34:   return(0);
 35: }

 37: static PetscErrorCode DMDAGetElements_2D(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
 38: {
 40:   DM_DA          *da = (DM_DA*)dm->data;
 41:   PetscInt       i,xs,xe,Xs,Xe;
 42:   PetscInt       j,ys,ye,Ys,Ye;
 43:   PetscInt       cnt=0, cell[4], ns=2;
 44:   PetscInt       c, split[] = {0,1,3,
 45:                                2,3,1};

 48:   if (!da->e) {
 49:     PetscInt corners[4],nn = 0;

 51:     if (!da->s) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Cannot get elements for DMDA with zero stencil width");

 53:     switch (da->elementtype) {
 54:     case DMDA_ELEMENT_Q1:
 55:       da->nen = 4;
 56:       break;
 57:     case DMDA_ELEMENT_P1:
 58:       da->nen = 3;
 59:       break;
 60:     default:
 61:       SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Unknown element type %d",da->elementtype);
 62:     }
 63:     nn = da->nen;

 65:     if (da->elementtype == DMDA_ELEMENT_P1) {ns=2;}
 66:     if (da->elementtype == DMDA_ELEMENT_Q1) {ns=1;}
 67:     DMDAGetCorners(dm,&xs,&ys,NULL,&xe,&ye,NULL);
 68:     DMDAGetGhostCorners(dm,&Xs,&Ys,NULL,&Xe,&Ye,NULL);
 69:     xe    += xs; Xe += Xs; if (xs != Xs) xs -= 1;
 70:     ye    += ys; Ye += Ys; if (ys != Ys) ys -= 1;
 71:     da->ne = ns*(xe - xs - 1)*(ye - ys - 1);
 72:     PetscMalloc1(1 + nn*da->ne,&da->e);
 73:     for (j=ys; j<ye-1; j++) {
 74:       for (i=xs; i<xe-1; i++) {
 75:         cell[0] = (i-Xs)   + (j-Ys)*(Xe-Xs);
 76:         cell[1] = (i-Xs+1) + (j-Ys)*(Xe-Xs);
 77:         cell[2] = (i-Xs+1) + (j-Ys+1)*(Xe-Xs);
 78:         cell[3] = (i-Xs)   + (j-Ys+1)*(Xe-Xs);
 79:         if (da->elementtype == DMDA_ELEMENT_P1) {
 80:           for (c=0; c<ns*nn; c++) da->e[cnt++] = cell[split[c]];
 81:         }
 82:         if (da->elementtype == DMDA_ELEMENT_Q1) {
 83:           for (c=0; c<ns*nn; c++) da->e[cnt++] = cell[c];
 84:         }
 85:       }
 86:     }

 88:     corners[0] = (xs  -Xs) + (ys  -Ys)*(Xe-Xs);
 89:     corners[1] = (xe-1-Xs) + (ys  -Ys)*(Xe-Xs);
 90:     corners[2] = (xs  -Xs) + (ye-1-Ys)*(Xe-Xs);
 91:     corners[3] = (xe-1-Xs) + (ye-1-Ys)*(Xe-Xs);
 92:     ISCreateGeneral(PETSC_COMM_SELF,4,corners,PETSC_COPY_VALUES,&da->ecorners);
 93:   }
 94:   *nel = da->ne;
 95:   *nen = da->nen;
 96:   *e   = da->e;
 97:   return(0);
 98: }

100: static PetscErrorCode DMDAGetElements_3D(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
101: {
103:   DM_DA          *da = (DM_DA*)dm->data;
104:   PetscInt       i,xs,xe,Xs,Xe;
105:   PetscInt       j,ys,ye,Ys,Ye;
106:   PetscInt       k,zs,ze,Zs,Ze;
107:   PetscInt       cnt=0, cell[8], ns=6;
108:   PetscInt       c, split[] = {0,1,3,7,
109:                                0,1,7,4,
110:                                1,2,3,7,
111:                                1,2,7,6,
112:                                1,4,5,7,
113:                                1,5,6,7};

116:   if (!da->e) {
117:     PetscInt corners[8],nn = 0;

119:     if (!da->s) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Cannot get elements for DMDA with zero stencil width");

121:     switch (da->elementtype) {
122:     case DMDA_ELEMENT_Q1:
123:       da->nen = 8;
124:       break;
125:     case DMDA_ELEMENT_P1:
126:       da->nen = 4;
127:       break;
128:     default:
129:       SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Unknown element type %d",da->elementtype);
130:     }
131:     nn = da->nen;

133:     if (da->elementtype == DMDA_ELEMENT_P1) {ns=6;}
134:     if (da->elementtype == DMDA_ELEMENT_Q1) {ns=1;}
135:     DMDAGetCorners(dm,&xs,&ys,&zs,&xe,&ye,&ze);
136:     DMDAGetGhostCorners(dm,&Xs,&Ys,&Zs,&Xe,&Ye,&Ze);
137:     xe    += xs; Xe += Xs; if (xs != Xs) xs -= 1;
138:     ye    += ys; Ye += Ys; if (ys != Ys) ys -= 1;
139:     ze    += zs; Ze += Zs; if (zs != Zs) zs -= 1;
140:     da->ne = ns*(xe - xs - 1)*(ye - ys - 1)*(ze - zs - 1);
141:     PetscMalloc1(1 + nn*da->ne,&da->e);
142:     for (k=zs; k<ze-1; k++) {
143:       for (j=ys; j<ye-1; j++) {
144:         for (i=xs; i<xe-1; i++) {
145:           cell[0] = (i  -Xs) + (j  -Ys)*(Xe-Xs) + (k  -Zs)*(Xe-Xs)*(Ye-Ys);
146:           cell[1] = (i+1-Xs) + (j  -Ys)*(Xe-Xs) + (k  -Zs)*(Xe-Xs)*(Ye-Ys);
147:           cell[2] = (i+1-Xs) + (j+1-Ys)*(Xe-Xs) + (k  -Zs)*(Xe-Xs)*(Ye-Ys);
148:           cell[3] = (i  -Xs) + (j+1-Ys)*(Xe-Xs) + (k  -Zs)*(Xe-Xs)*(Ye-Ys);
149:           cell[4] = (i  -Xs) + (j  -Ys)*(Xe-Xs) + (k+1-Zs)*(Xe-Xs)*(Ye-Ys);
150:           cell[5] = (i+1-Xs) + (j  -Ys)*(Xe-Xs) + (k+1-Zs)*(Xe-Xs)*(Ye-Ys);
151:           cell[6] = (i+1-Xs) + (j+1-Ys)*(Xe-Xs) + (k+1-Zs)*(Xe-Xs)*(Ye-Ys);
152:           cell[7] = (i  -Xs) + (j+1-Ys)*(Xe-Xs) + (k+1-Zs)*(Xe-Xs)*(Ye-Ys);
153:           if (da->elementtype == DMDA_ELEMENT_P1) {
154:             for (c=0; c<ns*nn; c++) da->e[cnt++] = cell[split[c]];
155:           }
156:           if (da->elementtype == DMDA_ELEMENT_Q1) {
157:             for (c=0; c<ns*nn; c++) da->e[cnt++] = cell[c];
158:           }
159:         }
160:       }
161:     }

163:     corners[0] = (xs  -Xs) + (ys  -Ys)*(Xe-Xs) + (zs-  Zs)*(Xe-Xs)*(Ye-Ys);
164:     corners[1] = (xe-1-Xs) + (ys  -Ys)*(Xe-Xs) + (zs-  Zs)*(Xe-Xs)*(Ye-Ys);
165:     corners[2] = (xs  -Xs) + (ye-1-Ys)*(Xe-Xs) + (zs-  Zs)*(Xe-Xs)*(Ye-Ys);
166:     corners[3] = (xe-1-Xs) + (ye-1-Ys)*(Xe-Xs) + (zs-  Zs)*(Xe-Xs)*(Ye-Ys);
167:     corners[4] = (xs  -Xs) + (ys  -Ys)*(Xe-Xs) + (ze-1-Zs)*(Xe-Xs)*(Ye-Ys);
168:     corners[5] = (xe-1-Xs) + (ys  -Ys)*(Xe-Xs) + (ze-1-Zs)*(Xe-Xs)*(Ye-Ys);
169:     corners[6] = (xs  -Xs) + (ye-1-Ys)*(Xe-Xs) + (ze-1-Zs)*(Xe-Xs)*(Ye-Ys);
170:     corners[7] = (xe-1-Xs) + (ye-1-Ys)*(Xe-Xs) + (ze-1-Zs)*(Xe-Xs)*(Ye-Ys);
171:     ISCreateGeneral(PETSC_COMM_SELF,8,corners,PETSC_COPY_VALUES,&da->ecorners);
172:   }
173:   *nel = da->ne;
174:   *nen = da->nen;
175:   *e   = da->e;
176:   return(0);
177: }

179: /*@
180:    DMDAGetElementsCorners - Returns the global (x,y,z) indices of the lower left
181:    corner of the non-overlapping decomposition identified by DMDAGetElements()

183:     Not Collective

185:    Input Parameter:
186: .     da - the DM object

188:    Output Parameters:
189: +     gx - the x index
190: .     gy - the y index
191: -     gz - the z index

193:    Level: intermediate

195:    Notes:

197: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetElements()
198: @*/
199: PetscErrorCode  DMDAGetElementsCorners(DM da, PetscInt *gx, PetscInt *gy, PetscInt *gz)
200: {
201:   PetscInt       xs,Xs;
202:   PetscInt       ys,Ys;
203:   PetscInt       zs,Zs;
204:   PetscBool      isda;

212:   PetscObjectTypeCompare((PetscObject)da,DMDA,&isda);
213:   if (!isda) SETERRQ1(PetscObjectComm((PetscObject)da),PETSC_ERR_USER,"Not for DM type %s",((PetscObject)da)->type_name);
214:   DMDAGetCorners(da,&xs,&ys,&zs,NULL,NULL,NULL);
215:   DMDAGetGhostCorners(da,&Xs,&Ys,&Zs,NULL,NULL,NULL);
216:   if (xs != Xs) xs -= 1;
217:   if (ys != Ys) ys -= 1;
218:   if (zs != Zs) zs -= 1;
219:   if (gx) *gx  = xs;
220:   if (gy) *gy  = ys;
221:   if (gz) *gz  = zs;
222:   return(0);
223: }

225: /*@
226:       DMDAGetElementsSizes - Gets the local number of elements per direction for the non-overlapping decomposition identified by DMDAGetElements()

228:     Not Collective

230:    Input Parameter:
231: .     da - the DM object

233:    Output Parameters:
234: +     mx - number of local elements in x-direction
235: .     my - number of local elements in y-direction
236: -     mz - number of local elements in z-direction

238:    Level: intermediate

240:    Notes:
241:     It returns the same number of elements, irrespective of the DMDAElementType

243: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetElements
244: @*/
245: PetscErrorCode  DMDAGetElementsSizes(DM da, PetscInt *mx, PetscInt *my, PetscInt *mz)
246: {
247:   PetscInt       xs,xe,Xs;
248:   PetscInt       ys,ye,Ys;
249:   PetscInt       zs,ze,Zs;
250:   PetscInt       dim;
251:   PetscBool      isda;

259:   PetscObjectTypeCompare((PetscObject)da,DMDA,&isda);
260:   if (!isda) SETERRQ1(PetscObjectComm((PetscObject)da),PETSC_ERR_USER,"Not for DM type %s",((PetscObject)da)->type_name);
261:   DMDAGetCorners(da,&xs,&ys,&zs,&xe,&ye,&ze);
262:   DMDAGetGhostCorners(da,&Xs,&Ys,&Zs,NULL,NULL,NULL);
263:   xe  += xs; if (xs != Xs) xs -= 1;
264:   ye  += ys; if (ys != Ys) ys -= 1;
265:   ze  += zs; if (zs != Zs) zs -= 1;
266:   if (mx) *mx  = 0;
267:   if (my) *my  = 0;
268:   if (mz) *mz  = 0;
269:   DMGetDimension(da,&dim);
270:   switch (dim) {
271:   case 3:
272:     if (mz) *mz = ze - zs - 1;
273:   case 2:
274:     if (my) *my = ye - ys - 1;
275:   case 1:
276:     if (mx) *mx = xe - xs - 1;
277:     break;
278:   }
279:   return(0);
280: }

282: /*@
283:       DMDASetElementType - Sets the element type to be returned by DMDAGetElements()

285:     Not Collective

287:    Input Parameter:
288: .     da - the DMDA object

290:    Output Parameters:
291: .     etype - the element type, currently either DMDA_ELEMENT_P1 or DMDA_ELEMENT_Q1

293:    Level: intermediate

295: .seealso: DMDAElementType, DMDAGetElementType(), DMDAGetElements(), DMDARestoreElements()
296: @*/
297: PetscErrorCode  DMDASetElementType(DM da, DMDAElementType etype)
298: {
299:   DM_DA          *dd = (DM_DA*)da->data;
301:   PetscBool      isda;

306:   PetscObjectTypeCompare((PetscObject)da,DMDA,&isda);
307:   if (!isda) return(0);
308:   if (dd->elementtype != etype) {
309:     PetscFree(dd->e);
310:     ISDestroy(&dd->ecorners);

312:     dd->elementtype = etype;
313:     dd->ne          = 0;
314:     dd->nen         = 0;
315:     dd->e           = NULL;
316:   }
317:   return(0);
318: }

320: /*@
321:       DMDAGetElementType - Gets the element type to be returned by DMDAGetElements()

323:     Not Collective

325:    Input Parameter:
326: .     da - the DMDA object

328:    Output Parameters:
329: .     etype - the element type, currently either DMDA_ELEMENT_P1 or DMDA_ELEMENT_Q1

331:    Level: intermediate

333: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetElements(), DMDARestoreElements()
334: @*/
335: PetscErrorCode  DMDAGetElementType(DM da, DMDAElementType *etype)
336: {
337:   DM_DA          *dd = (DM_DA*)da->data;
339:   PetscBool      isda;

344:   PetscObjectTypeCompare((PetscObject)da,DMDA,&isda);
345:   if (!isda) SETERRQ1(PetscObjectComm((PetscObject)da),PETSC_ERR_USER,"Not for DM type %s",((PetscObject)da)->type_name);
346:   *etype = dd->elementtype;
347:   return(0);
348: }

350: /*@C
351:       DMDAGetElements - Gets an array containing the indices (in local coordinates)
352:                  of all the local elements

354:     Not Collective

356:    Input Parameter:
357: .     dm - the DM object

359:    Output Parameters:
360: +     nel - number of local elements
361: .     nen - number of element nodes
362: -     e - the local indices of the elements' vertices

364:    Level: intermediate

366:    Notes:
367:      Call DMDARestoreElements() once you have finished accessing the elements.

369:      Each process uniquely owns a subset of the elements. That is no element is owned by two or more processes.

371:      If on each process you integrate over its owned elements and use ADD_VALUES in Vec/MatSetValuesLocal() then you'll obtain the correct result.

373:      Not supported in Fortran

375: .seealso: DMDAElementType, DMDASetElementType(), VecSetValuesLocal(), MatSetValuesLocal(), DMGlobalToLocalBegin(), DMLocalToGlobalBegin()
376: @*/
377: PetscErrorCode  DMDAGetElements(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
378: {
379:   PetscInt       dim;
381:   DM_DA          *dd = (DM_DA*)dm->data;
382:   PetscBool      isda;

389:   PetscObjectTypeCompare((PetscObject)dm,DMDA,&isda);
390:   if (!isda) SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_USER,"Not for DM type %s",((PetscObject)dm)->type_name);
391:   if (dd->stencil_type == DMDA_STENCIL_STAR) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"DMDAGetElements() requires you use a stencil type of DMDA_STENCIL_BOX");
392:   DMGetDimension(dm, &dim);
393:   if (dd->e) {
394:     *nel = dd->ne;
395:     *nen = dd->nen;
396:     *e   = dd->e;
397:     return(0);
398:   }
399:   if (dim==-1) {
400:     *nel = 0; *nen = 0; *e = NULL;
401:   } else if (dim==1) {
402:     DMDAGetElements_1D(dm,nel,nen,e);
403:   } else if (dim==2) {
404:     DMDAGetElements_2D(dm,nel,nen,e);
405:   } else if (dim==3) {
406:     DMDAGetElements_3D(dm,nel,nen,e);
407:   } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"DMDA dimension not 1, 2, or 3, it is %D\n",dim);
408:   return(0);
409: }

411: /*@
412:       DMDAGetSubdomainCornersIS - Gets an index set containing the corner indices (in local coordinates)
413:                                  of the non-overlapping decomposition identified by DMDAGetElements

415:     Not Collective

417:    Input Parameter:
418: .     dm - the DM object

420:    Output Parameters:
421: .     is - the index set

423:    Level: intermediate

425:    Notes:
426:     Call DMDARestoreSubdomainCornersIS() once you have finished accessing the index set.

428: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetElements(), DMDARestoreElementsCornersIS()
429: @*/
430: PetscErrorCode  DMDAGetSubdomainCornersIS(DM dm,IS *is)
431: {
433:   DM_DA          *dd = (DM_DA*)dm->data;
434:   PetscBool      isda;

439:   PetscObjectTypeCompare((PetscObject)dm,DMDA,&isda);
440:   if (!isda) SETERRQ1(PetscObjectComm((PetscObject)dm),PETSC_ERR_USER,"Not for DM type %s",((PetscObject)dm)->type_name);
441:   if (dd->stencil_type == DMDA_STENCIL_STAR) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"DMDAGetElement() requires you use a stencil type of DMDA_STENCIL_BOX");
442:   if (!dd->ecorners) { /* compute elements if not yet done */
443:     const PetscInt *e;
444:     PetscInt       nel,nen;

446:     DMDAGetElements(dm,&nel,&nen,&e);
447:     DMDARestoreElements(dm,&nel,&nen,&e);
448:   }
449:   *is = dd->ecorners;
450:   return(0);
451: }

453: /*@C
454:       DMDARestoreElements - Restores the array obtained with DMDAGetElements()

456:     Not Collective

458:    Input Parameter:
459: +     dm - the DM object
460: .     nel - number of local elements
461: .     nen - number of element nodes
462: -     e - the local indices of the elements' vertices

464:    Level: intermediate

466:    Note: You should not access these values after you have called this routine.

468:          This restore signals the DMDA object that you no longer need access to the array information.

470:          Not supported in Fortran

472: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetElements()
473: @*/
474: PetscErrorCode  DMDARestoreElements(DM dm,PetscInt *nel,PetscInt *nen,const PetscInt *e[])
475: {
481:   *nel = 0;
482:   *nen = -1;
483:   *e = NULL;
484:   return(0);
485: }

487: /*@
488:       DMDARestoreSubdomainCornersIS - Restores the IS obtained with DMDAGetSubdomainCornersIS()

490:     Not Collective

492:    Input Parameter:
493: +     dm - the DM object
494: -     is - the index set

496:    Level: intermediate

498:    Note:

500: .seealso: DMDAElementType, DMDASetElementType(), DMDAGetSubdomainCornersIS()
501: @*/
502: PetscErrorCode  DMDARestoreSubdomainCornersIS(DM dm,IS *is)
503: {
507:   *is = NULL;
508:   return(0);
509: }