Actual source code: dasub.c

petsc-3.12.2 2019-11-22
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  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,y,z - the physical coordinates

 17:    Output Parameters:
 18: +   II, JJ, KK - the logical coordinate (-1 on processes that do not contain that point)
 19: -   X, Y, Z, - (optional) the coordinates of the located grid point

 21:    Level: advanced

 23:    Notes:
 24:    All processors that share the DMDA must call this with the same coordinate value

 26: @*/
 27: PetscErrorCode  DMDAGetLogicalCoordinate(DM da,PetscScalar x,PetscScalar y,PetscScalar z,PetscInt *II,PetscInt *JJ,PetscInt *KK,PetscScalar *X,PetscScalar *Y,PetscScalar *Z)
 28: {
 30:   Vec            coors;
 31:   DM             dacoors;
 32:   DMDACoor2d     **c;
 33:   PetscInt       i,j,xs,xm,ys,ym;
 34:   PetscReal      d,D = PETSC_MAX_REAL,Dv;
 35:   PetscMPIInt    rank,root;

 38:   if (da->dim == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get point from 1d DMDA");
 39:   if (da->dim == 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get point from 3d DMDA");

 41:   *II = -1;
 42:   *JJ = -1;

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

 77: /*@
 78:    DMDAGetRay - Returns a vector on process zero that contains a row or column of the values in a DMDA vector

 80:    Collective on DMDA

 82:    Input Parameters:
 83: +  da - the distributed array
 84: .  vec - the vector
 85: .  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z
 86: -  gp - global grid point number in this direction

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

 92:    Level: advanced

 94:    Notes:
 95:    All processors that share the DMDA must call this with the same gp value

 97: @*/
 98: PetscErrorCode  DMDAGetRay(DM da,DMDADirection dir,PetscInt gp,Vec *newvec,VecScatter *scatter)
 99: {
100:   PetscMPIInt    rank;
101:   DM_DA          *dd = (DM_DA*)da->data;
103:   IS             is;
104:   AO             ao;
105:   Vec            vec;
106:   PetscInt       *indices,i,j;

109:   if (da->dim == 3) SETERRQ(PetscObjectComm((PetscObject) da), PETSC_ERR_SUP, "Cannot get slice from 3d DMDA");
110:   MPI_Comm_rank(PetscObjectComm((PetscObject) da), &rank);
111:   DMDAGetAO(da, &ao);
112:   if (!rank) {
113:     if (da->dim == 1) {
114:       if (dir == DMDA_X) {
115:         PetscMalloc1(dd->w, &indices);
116:         indices[0] = dd->w*gp;
117:         for (i = 1; i < dd->w; ++i) indices[i] = indices[i-1] + 1;
118:         AOApplicationToPetsc(ao, dd->w, indices);
119:         VecCreate(PETSC_COMM_SELF, newvec);
120:         VecSetBlockSize(*newvec, dd->w);
121:         VecSetSizes(*newvec, dd->w, PETSC_DETERMINE);
122:         VecSetType(*newvec, VECSEQ);
123:         ISCreateGeneral(PETSC_COMM_SELF, dd->w, indices, PETSC_OWN_POINTER, &is);
124:       } else if (dir == DMDA_Y) SETERRQ(PetscObjectComm((PetscObject) da), PETSC_ERR_SUP, "Cannot get Y slice from 1d DMDA");
125:       else SETERRQ(PetscObjectComm((PetscObject) da), PETSC_ERR_ARG_OUTOFRANGE, "Unknown DMDADirection");
126:     } else {
127:       if (dir == DMDA_Y) {
128:         PetscMalloc1(dd->w*dd->M,&indices);
129:         indices[0] = gp*dd->M*dd->w;
130:         for (i=1; i<dd->M*dd->w; i++) indices[i] = indices[i-1] + 1;

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

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

170:    Collective on da

172:    Input Parameters:
173: +  da - the distributed array
174: .  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z
175: -  gp - global grid point number in this direction

177:    Output Parameters:
178: .  comm - new communicator

180:    Level: advanced

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

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

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

191:    Not supported from Fortran

193: @*/
194: PetscErrorCode  DMDAGetProcessorSubset(DM da,DMDADirection dir,PetscInt gp,MPI_Comm *comm)
195: {
196:   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;

204:   flag = 0;
205:   DMDAGetCorners(da,&xs,&ys,&zs,&xm,&ym,&zm);
206:   MPI_Comm_size(PetscObjectComm((PetscObject)da),&size);
207:   if (dir == DMDA_Z) {
208:     if (da->dim < 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Z invalid for DMDA dim < 3");
209:     if (gp < 0 || gp > dd->P) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
210:     if (gp >= zs && gp < zs+zm) flag = 1;
211:   } else if (dir == DMDA_Y) {
212:     if (da->dim == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Y invalid for DMDA dim = 1");
213:     if (gp < 0 || gp > dd->N) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
214:     if (gp >= ys && gp < ys+ym) flag = 1;
215:   } else if (dir == DMDA_X) {
216:     if (gp < 0 || gp > dd->M) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
217:     if (gp >= xs && gp < xs+xm) flag = 1;
218:   } else SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

220:   PetscMalloc2(size,&owners,size,&ranks);
221:   MPI_Allgather(&flag,1,MPIU_INT,owners,1,MPIU_INT,PetscObjectComm((PetscObject)da));
222:   ict  = 0;
223:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",da->dim,(int)dir);
224:   for (i=0; i<size; i++) {
225:     if (owners[i]) {
226:       ranks[ict] = i; ict++;
227:       PetscInfo1(da,"%D ",i);
228:     }
229:   }
230:   PetscInfo(da,"\n");
231:   MPI_Comm_group(PetscObjectComm((PetscObject)da),&group);
232:   MPI_Group_incl(group,ict,ranks,&subgroup);
233:   MPI_Comm_create(PetscObjectComm((PetscObject)da),subgroup,comm);
234:   MPI_Group_free(&subgroup);
235:   MPI_Group_free(&group);
236:   PetscFree2(owners,ranks);
237:   return(0);
238: }

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

245:    Collective on da

247:    Input Parameters:
248: +  da - the distributed array
249: -  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z

251:    Output Parameters:
252: .  subcomm - new communicator

254:    Level: advanced

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

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

261:    Not supported from Fortran

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

276:   PetscObjectGetComm((PetscObject)da,&comm);
277:   DMDAGetCorners(da, &xs, &ys, &zs, &xm, &ym, &zm);
278:   MPI_Comm_size(comm, &size);
279:   if (dir == DMDA_Z) {
280:     if (da->dim < 3) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Z invalid for DMDA dim < 3");
281:     firstPoint = zs;
282:   } else if (dir == DMDA_Y) {
283:     if (da->dim == 1) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Y invalid for DMDA dim = 1");
284:     firstPoint = ys;
285:   } else if (dir == DMDA_X) {
286:     firstPoint = xs;
287:   } else SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

289:   PetscMalloc2(size, &firstPoints, size, &subgroupRanks);
290:   MPI_Allgather(&firstPoint, 1, MPIU_INT, firstPoints, 1, MPIU_INT, comm);
291:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",da->dim,(int)dir);
292:   for (p = 0; p < size; ++p) {
293:     if (firstPoints[p] == firstPoint) {
294:       subgroupRanks[subgroupSize++] = p;
295:       PetscInfo1(da, "%D ", p);
296:     }
297:   }
298:   PetscInfo(da, "\n");
299:   MPI_Comm_group(comm, &group);
300:   MPI_Group_incl(group, subgroupSize, subgroupRanks, &subgroup);
301:   MPI_Comm_create(comm, subgroup, subcomm);
302:   MPI_Group_free(&subgroup);
303:   MPI_Group_free(&group);
304:   PetscFree2(firstPoints, subgroupRanks);
305:   return(0);
306: }