Actual source code: dasub.c

petsc-3.4.4 2014-03-13
  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 == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get slice from 1d DMDA");
117:   if (dd->dim == 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_SUP,"Cannot get slice from 3d DMDA");
118:   DMDAGetAO(da,&ao);
119:   MPI_Comm_rank(PetscObjectComm((PetscObject)da),&rank);
120:   if (!rank) {
121:     if (dir == DMDA_Y) {
122:       PetscMalloc(dd->w*dd->M*sizeof(PetscInt),&indices);
123:       indices[0] = gp*dd->M*dd->w;
124:       for (i=1; i<dd->M*dd->w; i++) indices[i] = indices[i-1] + 1;

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

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

165:    Collective on DMDA

167:    Input Parameters:
168: +  da - the distributed array
169: .  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z
170: -  gp - global grid point number in this direction

172:    Output Parameters:
173: .  comm - new communicator

175:    Level: advanced

177:    Notes:
178:    All processors that share the DMDA must call this with the same gp value

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

184: .keywords: distributed array, get, processor subset
185: @*/
186: PetscErrorCode  DMDAGetProcessorSubset(DM da,DMDADirection dir,PetscInt gp,MPI_Comm *comm)
187: {
188:   MPI_Group      group,subgroup;
190:   PetscInt       i,ict,flag,*owners,xs,xm,ys,ym,zs,zm;
191:   PetscMPIInt    size,*ranks = NULL;
192:   DM_DA          *dd = (DM_DA*)da->data;

196:   flag = 0;
197:   DMDAGetCorners(da,&xs,&ys,&zs,&xm,&ym,&zm);
198:   MPI_Comm_size(PetscObjectComm((PetscObject)da),&size);
199:   if (dir == DMDA_Z) {
200:     if (dd->dim < 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Z invalid for DMDA dim < 3");
201:     if (gp < 0 || gp > dd->P) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
202:     if (gp >= zs && gp < zs+zm) flag = 1;
203:   } else if (dir == DMDA_Y) {
204:     if (dd->dim == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Y invalid for DMDA dim = 1");
205:     if (gp < 0 || gp > dd->N) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
206:     if (gp >= ys && gp < ys+ym) flag = 1;
207:   } else if (dir == DMDA_X) {
208:     if (gp < 0 || gp > dd->M) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"invalid grid point");
209:     if (gp >= xs && gp < xs+xm) flag = 1;
210:   } else SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

212:   PetscMalloc2(size,PetscInt,&owners,size,PetscMPIInt,&ranks);
213:   MPI_Allgather(&flag,1,MPIU_INT,owners,1,MPIU_INT,PetscObjectComm((PetscObject)da));
214:   ict  = 0;
215:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",dd->dim,(int)dir);
216:   for (i=0; i<size; i++) {
217:     if (owners[i]) {
218:       ranks[ict] = i; ict++;
219:       PetscInfo1(da,"%D ",i);
220:     }
221:   }
222:   PetscInfo(da,"\n");
223:   MPI_Comm_group(PetscObjectComm((PetscObject)da),&group);
224:   MPI_Group_incl(group,ict,ranks,&subgroup);
225:   MPI_Comm_create(PetscObjectComm((PetscObject)da),subgroup,comm);
226:   MPI_Group_free(&subgroup);
227:   MPI_Group_free(&group);
228:   PetscFree2(owners,ranks);
229:   return(0);
230: }

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

239:    Collective on DMDA

241:    Input Parameters:
242: +  da - the distributed array
243: -  dir - Cartesian direction, either DMDA_X, DMDA_Y, or DMDA_Z

245:    Output Parameters:
246: .  subcomm - new communicator

248:    Level: advanced

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

253: .keywords: distributed array, get, processor subset
254: @*/
255: PetscErrorCode  DMDAGetProcessorSubsets(DM da, DMDADirection dir, MPI_Comm *subcomm)
256: {
257:   MPI_Comm       comm;
258:   MPI_Group      group, subgroup;
259:   PetscInt       subgroupSize = 0;
260:   PetscInt       *firstPoints;
261:   PetscMPIInt    size, *subgroupRanks = NULL;
262:   PetscInt       xs, xm, ys, ym, zs, zm, firstPoint, p;
264:   DM_DA          *dd = (DM_DA*)da->data;

268:   PetscObjectGetComm((PetscObject)da,&comm);
269:   DMDAGetCorners(da, &xs, &ys, &zs, &xm, &ym, &zm);
270:   MPI_Comm_size(comm, &size);
271:   if (dir == DMDA_Z) {
272:     if (dd->dim < 3) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Z invalid for DMDA dim < 3");
273:     firstPoint = zs;
274:   } else if (dir == DMDA_Y) {
275:     if (dd->dim == 1) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DMDA_Y invalid for DMDA dim = 1");
276:     firstPoint = ys;
277:   } else if (dir == DMDA_X) {
278:     firstPoint = xs;
279:   } else SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"Invalid direction");

281:   PetscMalloc2(size, PetscInt, &firstPoints, size, PetscMPIInt, &subgroupRanks);
282:   MPI_Allgather(&firstPoint, 1, MPIU_INT, firstPoints, 1, MPIU_INT, comm);
283:   PetscInfo2(da,"DMDAGetProcessorSubset: dim=%D, direction=%d, procs: ",dd->dim,(int)dir);
284:   for (p = 0; p < size; ++p) {
285:     if (firstPoints[p] == firstPoint) {
286:       subgroupRanks[subgroupSize++] = p;
287:       PetscInfo1(da, "%D ", p);
288:     }
289:   }
290:   PetscInfo(da, "\n");
291:   MPI_Comm_group(comm, &group);
292:   MPI_Group_incl(group, subgroupSize, subgroupRanks, &subgroup);
293:   MPI_Comm_create(comm, subgroup, subcomm);
294:   MPI_Group_free(&subgroup);
295:   MPI_Group_free(&group);
296:   PetscFree2(firstPoints, subgroupRanks);
297:   return(0);
298: }