Actual source code: dasub.c

petsc-3.5.2 2014-09-08
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  2: /*
  3:   Code for manipulating distributed regular arrays in parallel.
  4: */

  6: #include <petsc-private/dmdaimpl.h>    /*I   "petscdmda.h"   I*/

 10: /*@C
 11:    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

 13:    Collective on DMDA

 15:    Input Parameters:
 16: +  da - the distributed array
 17: -  x,y,z - the physical coordinates

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

 23:    Level: advanced

 25:    Notes:
 26:    All processors that share the DMDA must call this with the same coordinate value

 28: .keywords: distributed array, get, processor subset
 29: @*/
 30: PetscErrorCode  DMDAGetLogicalCoordinate(DM da,PetscScalar x,PetscScalar y,PetscScalar z,PetscInt *II,PetscInt *JJ,PetscInt *KK,PetscScalar *X,PetscScalar *Y,PetscScalar *Z)
 31: {
 32:   DM_DA          *dd = (DM_DA*)da->data;
 34:   Vec            coors;
 35:   DM             dacoors;
 36:   DMDACoor2d     **c;
 37:   PetscInt       i,j,xs,xm,ys,ym;
 38:   PetscReal      d,D = PETSC_MAX_REAL,Dv;
 39:   PetscMPIInt    rank,root;

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

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

 48:   DMGetCoordinateDM(da,&dacoors);
 49:   DMDAGetCorners(dacoors,&xs,&ys,NULL,&xm,&ym,NULL);
 50:   DMGetCoordinates(da,&coors);
 51:   DMDAVecGetArray(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:   MPI_Allreduce(&D,&Dv,1,MPIU_REAL,MPI_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:   MPI_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:   DMDAVecRestoreArray(dacoors,coors,&c);
 78:   return(0);
 79: }

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

 86:    Collective on DMDA

 88:    Input Parameters:
 89: +  da - the distributed array
 90: .  vec - the vector
 91: .  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z
 92: -  gp - global grid point number in this direction

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

 98:    Level: advanced

100:    Notes:
101:    All processors that share the DMDA must call this with the same gp value

103: .keywords: distributed array, get, processor subset
104: @*/
105: PetscErrorCode  DMDAGetRay(DM da,DMDADirection dir,PetscInt gp,Vec *newvec,VecScatter *scatter)
106: {
107:   PetscMPIInt    rank;
108:   DM_DA          *dd = (DM_DA*)da->data;
110:   IS             is;
111:   AO             ao;
112:   Vec            vec;
113:   PetscInt       *indices,i,j;

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

139:         AOApplicationToPetsc(ao,dd->M*dd->w,indices);
140:         VecCreate(PETSC_COMM_SELF,newvec);
141:         VecSetBlockSize(*newvec,dd->w);
142:         VecSetSizes(*newvec,dd->M*dd->w,PETSC_DETERMINE);
143:         VecSetType(*newvec,VECSEQ);
144:         ISCreateGeneral(PETSC_COMM_SELF,dd->w*dd->M,indices,PETSC_OWN_POINTER,&is);
145:       } else if (dir == DMDA_X) {
146:         PetscMalloc1(dd->w*dd->N,&indices);
147:         indices[0] = dd->w*gp;
148:         for (j=1; j<dd->w; j++) indices[j] = indices[j-1] + 1;
149:         for (i=1; i<dd->N; i++) {
150:           indices[i*dd->w] = indices[i*dd->w-1] + dd->w*dd->M - dd->w + 1;
151:           for (j=1; j<dd->w; j++) indices[i*dd->w + j] = indices[i*dd->w + j - 1] + 1;
152:         }
153:         AOApplicationToPetsc(ao,dd->w*dd->N,indices);
154:         VecCreate(PETSC_COMM_SELF,newvec);
155:         VecSetBlockSize(*newvec,dd->w);
156:         VecSetSizes(*newvec,dd->N*dd->w,PETSC_DETERMINE);
157:         VecSetType(*newvec,VECSEQ);
158:         ISCreateGeneral(PETSC_COMM_SELF,dd->w*dd->N,indices,PETSC_OWN_POINTER,&is);
159:       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown DMDADirection");
160:     }
161:   } else {
162:     VecCreateSeq(PETSC_COMM_SELF, 0, newvec);
163:     ISCreateGeneral(PETSC_COMM_SELF, 0, 0, PETSC_COPY_VALUES, &is);
164:   }
165:   DMGetGlobalVector(da, &vec);
166:   VecScatterCreate(vec, is, *newvec, NULL, scatter);
167:   DMRestoreGlobalVector(da, &vec);
168:   ISDestroy(&is);
169:   return(0);
170: }

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

179:    Collective on DMDA

181:    Input Parameters:
182: +  da - the distributed array
183: .  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z
184: -  gp - global grid point number in this direction

186:    Output Parameters:
187: .  comm - new communicator

189:    Level: advanced

191:    Notes:
192:    All processors that share the DMDA must call this with the same gp value

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

198: .keywords: distributed array, get, processor subset
199: @*/
200: PetscErrorCode  DMDAGetProcessorSubset(DM da,DMDADirection dir,PetscInt gp,MPI_Comm *comm)
201: {
202:   MPI_Group      group,subgroup;
204:   PetscInt       i,ict,flag,*owners,xs,xm,ys,ym,zs,zm;
205:   PetscMPIInt    size,*ranks = NULL;
206:   DM_DA          *dd = (DM_DA*)da->data;

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

226:   PetscMalloc2(size,&owners,size,&ranks);
227:   MPI_Allgather(&flag,1,MPIU_INT,owners,1,MPIU_INT,PetscObjectComm((PetscObject)da));
228:   ict  = 0;
229:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",dd->dim,(int)dir);
230:   for (i=0; i<size; i++) {
231:     if (owners[i]) {
232:       ranks[ict] = i; ict++;
233:       PetscInfo1(da,"%D ",i);
234:     }
235:   }
236:   PetscInfo(da,"\n");
237:   MPI_Comm_group(PetscObjectComm((PetscObject)da),&group);
238:   MPI_Group_incl(group,ict,ranks,&subgroup);
239:   MPI_Comm_create(PetscObjectComm((PetscObject)da),subgroup,comm);
240:   MPI_Group_free(&subgroup);
241:   MPI_Group_free(&group);
242:   PetscFree2(owners,ranks);
243:   return(0);
244: }

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

253:    Collective on DMDA

255:    Input Parameters:
256: +  da - the distributed array
257: -  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z

259:    Output Parameters:
260: .  subcomm - new communicator

262:    Level: advanced

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

267: .keywords: distributed array, get, processor subset
268: @*/
269: PetscErrorCode  DMDAGetProcessorSubsets(DM da, DMDADirection dir, MPI_Comm *subcomm)
270: {
271:   MPI_Comm       comm;
272:   MPI_Group      group, subgroup;
273:   PetscInt       subgroupSize = 0;
274:   PetscInt       *firstPoints;
275:   PetscMPIInt    size, *subgroupRanks = NULL;
276:   PetscInt       xs, xm, ys, ym, zs, zm, firstPoint, p;
278:   DM_DA          *dd = (DM_DA*)da->data;

282:   PetscObjectGetComm((PetscObject)da,&comm);
283:   DMDAGetCorners(da, &xs, &ys, &zs, &xm, &ym, &zm);
284:   MPI_Comm_size(comm, &size);
285:   if (dir == DMDA_Z) {
286:     if (dd->dim < 3) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Z invalid for DMDA dim < 3");
287:     firstPoint = zs;
288:   } else if (dir == DMDA_Y) {
289:     if (dd->dim == 1) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Y invalid for DMDA dim = 1");
290:     firstPoint = ys;
291:   } else if (dir == DMDA_X) {
292:     firstPoint = xs;
293:   } else SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

295:   PetscMalloc2(size, &firstPoints, size, &subgroupRanks);
296:   MPI_Allgather(&firstPoint, 1, MPIU_INT, firstPoints, 1, MPIU_INT, comm);
297:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",dd->dim,(int)dir);
298:   for (p = 0; p < size; ++p) {
299:     if (firstPoints[p] == firstPoint) {
300:       subgroupRanks[subgroupSize++] = p;
301:       PetscInfo1(da, "%D ", p);
302:     }
303:   }
304:   PetscInfo(da, "\n");
305:   MPI_Comm_group(comm, &group);
306:   MPI_Group_incl(group, subgroupSize, subgroupRanks, &subgroup);
307:   MPI_Comm_create(comm, subgroup, subcomm);
308:   MPI_Group_free(&subgroup);
309:   MPI_Group_free(&group);
310:   PetscFree2(firstPoints, subgroupRanks);
311:   return(0);
312: }