Actual source code: dasub.c
petsc-3.7.1 2016-05-15
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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: {
     33:   Vec            coors;
     34:   DM             dacoors;
     35:   DMDACoor2d     **c;
     36:   PetscInt       i,j,xs,xm,ys,ym;
     37:   PetscReal      d,D = PETSC_MAX_REAL,Dv;
     38:   PetscMPIInt    rank,root;

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

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

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

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

     85:    Collective on DMDA

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

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

     97:    Level: advanced

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

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

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

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

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

    178:    Collective on DMDA

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

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

    188:    Level: advanced

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

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

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

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

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

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

    252:    Collective on DMDA

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

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

    261:    Level: advanced

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

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

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

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