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,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 DM_X, DM_Y, or DM_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,DMDirection 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 == DM_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 == DM_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 DMDirection");
    126:     } else {
    127:       if (dir == DM_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 == DM_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 DMDirection");
    153:     }
    154:   } else {
    155:     VecCreateSeq(PETSC_COMM_SELF, 0, newvec);
    156:     ISCreateGeneral(PETSC_COMM_SELF, 0, NULL, 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 DM_X, DM_Y, or DM_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,DMDirection 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 == DM_Z) {
    208:     if (da->dim < 3) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DM_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 == DM_Y) {
    212:     if (da->dim == 1) SETERRQ(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_OUTOFRANGE,"DM_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 == DM_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 DM_X, DM_Y, or DM_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, DMDirection 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 == DM_Z) {
    280:     if (da->dim < 3) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DM_Z invalid for DMDA dim < 3");
    281:     firstPoint = zs;
    282:   } else if (dir == DM_Y) {
    283:     if (da->dim == 1) SETERRQ(comm,PETSC_ERR_ARG_OUTOFRANGE,"DM_Y invalid for DMDA dim = 1");
    284:     firstPoint = ys;
    285:   } else if (dir == DM_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: }