Actual source code: dasub.c


  2: /*
  3:   Code for manipulating distributed regular arrays in parallel.
  4: */

  6: #include <petsc/private/dmdaimpl.h>

  8: /*@
  9:    DMDAGetLogicalCoordinate - Returns a the i,j,k logical coordinate for the closest mesh point to a x,y,z point in the coordinates of the DMDA

 11:    Collective on da

 13:    Input Parameters:
 14: +  da - the distributed array
 15: .  x  - the first physical coordinate
 16: .  y  - the second physical coordinate
 17: -  z  - the third physical coordinate

 19:    Output Parameters:
 20: +  II - the first logical coordinate (-1 on processes that do not contain that point)
 21: .  JJ - the second logical coordinate (-1 on processes that do not contain that point)
 22: .  KK - the third logical coordinate (-1 on processes that do not contain that point)
 23: .  X  - (optional) the first coordinate of the located grid point
 24: .  Y  - (optional) the second coordinate of the located grid point
 25: -  Z  - (optional) the third coordinate of the located grid point

 27:    Level: advanced

 29:    Notes:
 30:    All processors that share the DMDA must call this with the same coordinate value

 32: @*/
 33: PetscErrorCode  DMDAGetLogicalCoordinate(DM da,PetscScalar x,PetscScalar y,PetscScalar z,PetscInt *II,PetscInt *JJ,PetscInt *KK,PetscScalar *X,PetscScalar *Y,PetscScalar *Z)
 34: {
 35:   Vec            coors;
 36:   DM             dacoors;
 37:   DMDACoor2d     **c;
 38:   PetscInt       i,j,xs,xm,ys,ym;
 39:   PetscReal      d,D = PETSC_MAX_REAL,Dv;
 40:   PetscMPIInt    rank,root;


 45:   *II = -1;
 46:   *JJ = -1;

 48:   DMGetCoordinateDM(da,&dacoors);
 49:   DMDAGetCorners(dacoors,&xs,&ys,NULL,&xm,&ym,NULL);
 50:   DMGetCoordinates(da,&coors);
 51:   DMDAVecGetArrayRead(dacoors,coors,&c);
 52:   for (j=ys; j<ys+ym; j++) {
 53:     for (i=xs; i<xs+xm; i++) {
 54:       d = PetscSqrtReal(PetscRealPart((c[j][i].x - x)*(c[j][i].x - x) + (c[j][i].y - y)*(c[j][i].y - y)));
 55:       if (d < D) {
 56:         D   = d;
 57:         *II = i;
 58:         *JJ = j;
 59:       }
 60:     }
 61:   }
 62:   MPIU_Allreduce(&D,&Dv,1,MPIU_REAL,MPIU_MIN,PetscObjectComm((PetscObject)da));
 63:   if (D != Dv) {
 64:     *II  = -1;
 65:     *JJ  = -1;
 66:     rank = 0;
 67:   } else {
 68:     *X = c[*JJ][*II].x;
 69:     *Y = c[*JJ][*II].y;
 70:     MPI_Comm_rank(PetscObjectComm((PetscObject)da),&rank);
 71:     rank++;
 72:   }
 73:   MPIU_Allreduce(&rank,&root,1,MPI_INT,MPI_SUM,PetscObjectComm((PetscObject)da));
 74:   root--;
 75:   MPI_Bcast(X,1,MPIU_SCALAR,root,PetscObjectComm((PetscObject)da));
 76:   MPI_Bcast(Y,1,MPIU_SCALAR,root,PetscObjectComm((PetscObject)da));
 77:   DMDAVecRestoreArrayRead(dacoors,coors,&c);
 78:   return 0;
 79: }

 81: /*@
 82:    DMDAGetRay - Returns a vector on process zero that contains a row or column of the values in a DMDA vector

 84:    Collective on DMDA

 86:    Input Parameters:
 87: +  da - the distributed array
 88: .  dir - Cartesian direction, either DM_X, DM_Y, or DM_Z
 89: -  gp - global grid point number in this direction

 91:    Output Parameters:
 92: +  newvec - the new vector that can hold the values (size zero on all processes except process 0)
 93: -  scatter - the VecScatter that will map from the original vector to the slice

 95:    Level: advanced

 97:    Notes:
 98:    All processors that share the DMDA must call this with the same gp value

100: @*/
101: PetscErrorCode  DMDAGetRay(DM da,DMDirection dir,PetscInt gp,Vec *newvec,VecScatter *scatter)
102: {
103:   PetscMPIInt    rank;
104:   DM_DA          *dd = (DM_DA*)da->data;
105:   IS             is;
106:   AO             ao;
107:   Vec            vec;
108:   PetscInt       *indices,i,j;

111:   MPI_Comm_rank(PetscObjectComm((PetscObject) da), &rank);
112:   DMDAGetAO(da, &ao);
113:   if (rank == 0) {
114:     if (da->dim == 1) {
115:       if (dir == DM_X) {
116:         PetscMalloc1(dd->w, &indices);
117:         indices[0] = dd->w*gp;
118:         for (i = 1; i < dd->w; ++i) indices[i] = indices[i-1] + 1;
119:         AOApplicationToPetsc(ao, dd->w, indices);
120:         VecCreate(PETSC_COMM_SELF, newvec);
121:         VecSetBlockSize(*newvec, dd->w);
122:         VecSetSizes(*newvec, dd->w, PETSC_DETERMINE);
123:         VecSetType(*newvec, VECSEQ);
124:         ISCreateGeneral(PETSC_COMM_SELF, dd->w, indices, PETSC_OWN_POINTER, &is);
126:       else SETERRQ(PetscObjectComm((PetscObject) da), PETSC_ERR_ARG_OUTOFRANGE, "Unknown DMDirection");
127:     } else {
128:       if (dir == DM_Y) {
129:         PetscMalloc1(dd->w*dd->M,&indices);
130:         indices[0] = gp*dd->M*dd->w;
131:         for (i=1; i<dd->M*dd->w; i++) indices[i] = indices[i-1] + 1;

133:         AOApplicationToPetsc(ao,dd->M*dd->w,indices);
134:         VecCreate(PETSC_COMM_SELF,newvec);
135:         VecSetBlockSize(*newvec,dd->w);
136:         VecSetSizes(*newvec,dd->M*dd->w,PETSC_DETERMINE);
137:         VecSetType(*newvec,VECSEQ);
138:         ISCreateGeneral(PETSC_COMM_SELF,dd->w*dd->M,indices,PETSC_OWN_POINTER,&is);
139:       } else if (dir == DM_X) {
140:         PetscMalloc1(dd->w*dd->N,&indices);
141:         indices[0] = dd->w*gp;
142:         for (j=1; j<dd->w; j++) indices[j] = indices[j-1] + 1;
143:         for (i=1; i<dd->N; i++) {
144:           indices[i*dd->w] = indices[i*dd->w-1] + dd->w*dd->M - dd->w + 1;
145:           for (j=1; j<dd->w; j++) indices[i*dd->w + j] = indices[i*dd->w + j - 1] + 1;
146:         }
147:         AOApplicationToPetsc(ao,dd->w*dd->N,indices);
148:         VecCreate(PETSC_COMM_SELF,newvec);
149:         VecSetBlockSize(*newvec,dd->w);
150:         VecSetSizes(*newvec,dd->N*dd->w,PETSC_DETERMINE);
151:         VecSetType(*newvec,VECSEQ);
152:         ISCreateGeneral(PETSC_COMM_SELF,dd->w*dd->N,indices,PETSC_OWN_POINTER,&is);
153:       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown DMDirection");
154:     }
155:   } else {
156:     VecCreateSeq(PETSC_COMM_SELF, 0, newvec);
157:     ISCreateGeneral(PETSC_COMM_SELF, 0, NULL, PETSC_COPY_VALUES, &is);
158:   }
159:   DMGetGlobalVector(da, &vec);
160:   VecScatterCreate(vec, is, *newvec, NULL, scatter);
161:   DMRestoreGlobalVector(da, &vec);
162:   ISDestroy(&is);
163:   return 0;
164: }

166: /*@C
167:    DMDAGetProcessorSubset - Returns a communicator consisting only of the
168:    processors in a DMDA that own a particular global x, y, or z grid point
169:    (corresponding to a logical plane in a 3D grid or a line in a 2D grid).

171:    Collective on da

173:    Input Parameters:
174: +  da - the distributed array
175: .  dir - Cartesian direction, either DM_X, DM_Y, or DM_Z
176: -  gp - global grid point number in this direction

178:    Output Parameter:
179: .  comm - new communicator

181:    Level: advanced

183:    Notes:
184:    All processors that share the DMDA must call this with the same gp value

186:    After use, comm should be freed with MPI_Comm_free()

188:    This routine is particularly useful to compute boundary conditions
189:    or other application-specific calculations that require manipulating
190:    sets of data throughout a logical plane of grid points.

192:    Not supported from Fortran

194: @*/
195: PetscErrorCode  DMDAGetProcessorSubset(DM da,DMDirection dir,PetscInt gp,MPI_Comm *comm)
196: {
197:   MPI_Group      group,subgroup;
198:   PetscInt       i,ict,flag,*owners,xs,xm,ys,ym,zs,zm;
199:   PetscMPIInt    size,*ranks = NULL;
200:   DM_DA          *dd = (DM_DA*)da->data;

203:   flag = 0;
204:   DMDAGetCorners(da,&xs,&ys,&zs,&xm,&ym,&zm);
205:   MPI_Comm_size(PetscObjectComm((PetscObject)da),&size);
206:   if (dir == DM_Z) {
209:     if (gp >= zs && gp < zs+zm) flag = 1;
210:   } else if (dir == DM_Y) {
213:     if (gp >= ys && gp < ys+ym) flag = 1;
214:   } else if (dir == DM_X) {
216:     if (gp >= xs && gp < xs+xm) flag = 1;
217:   } else SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

219:   PetscMalloc2(size,&owners,size,&ranks);
220:   MPI_Allgather(&flag,1,MPIU_INT,owners,1,MPIU_INT,PetscObjectComm((PetscObject)da));
221:   ict  = 0;
222:   PetscInfo(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",da->dim,(int)dir);
223:   for (i=0; i<size; i++) {
224:     if (owners[i]) {
225:       ranks[ict] = i; ict++;
226:       PetscInfo(da,"%D ",i);
227:     }
228:   }
229:   PetscInfo(da,"\n");
230:   MPI_Comm_group(PetscObjectComm((PetscObject)da),&group);
231:   MPI_Group_incl(group,ict,ranks,&subgroup);
232:   MPI_Comm_create(PetscObjectComm((PetscObject)da),subgroup,comm);
233:   MPI_Group_free(&subgroup);
234:   MPI_Group_free(&group);
235:   PetscFree2(owners,ranks);
236:   return 0;
237: }

239: /*@C
240:    DMDAGetProcessorSubsets - Returns communicators consisting only of the
241:    processors in a DMDA adjacent in a particular dimension,
242:    corresponding to a logical plane in a 3D grid or a line in a 2D grid.

244:    Collective on da

246:    Input Parameters:
247: +  da - the distributed array
248: -  dir - Cartesian direction, either DM_X, DM_Y, or DM_Z

250:    Output Parameter:
251: .  subcomm - new communicator

253:    Level: advanced

255:    Notes:
256:    This routine is useful for distributing one-dimensional data in a tensor product grid.

258:    After use, comm should be freed with MPI_Comm_free()

260:    Not supported from Fortran

262: @*/
263: PetscErrorCode  DMDAGetProcessorSubsets(DM da, DMDirection dir, MPI_Comm *subcomm)
264: {
265:   MPI_Comm       comm;
266:   MPI_Group      group, subgroup;
267:   PetscInt       subgroupSize = 0;
268:   PetscInt       *firstPoints;
269:   PetscMPIInt    size, *subgroupRanks = NULL;
270:   PetscInt       xs, xm, ys, ym, zs, zm, firstPoint, p;

273:   PetscObjectGetComm((PetscObject)da,&comm);
274:   DMDAGetCorners(da, &xs, &ys, &zs, &xm, &ym, &zm);
275:   MPI_Comm_size(comm, &size);
276:   if (dir == DM_Z) {
278:     firstPoint = zs;
279:   } else if (dir == DM_Y) {
281:     firstPoint = ys;
282:   } else if (dir == DM_X) {
283:     firstPoint = xs;
284:   } else SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

286:   PetscMalloc2(size, &firstPoints, size, &subgroupRanks);
287:   MPI_Allgather(&firstPoint, 1, MPIU_INT, firstPoints, 1, MPIU_INT, comm);
288:   PetscInfo(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",da->dim,(int)dir);
289:   for (p = 0; p < size; ++p) {
290:     if (firstPoints[p] == firstPoint) {
291:       subgroupRanks[subgroupSize++] = p;
292:       PetscInfo(da, "%D ", p);
293:     }
294:   }
295:   PetscInfo(da, "\n");
296:   MPI_Comm_group(comm, &group);
297:   MPI_Group_incl(group, subgroupSize, subgroupRanks, &subgroup);
298:   MPI_Comm_create(comm, subgroup, subcomm);
299:   MPI_Group_free(&subgroup);
300:   MPI_Group_free(&group);
301:   PetscFree2(firstPoints, subgroupRanks);
302:   return 0;
303: }