Date: 2013-07-02T14:44:59+00:00

Actual source code: dasub.c
petsc-3.4.2 2013-07-02

      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: }