Actual source code: dasub.c

      1: /*
      2:   Code for manipulating distributed regular arrays in parallel.
      3: */

      5: #include <petsc/private/dmdaimpl.h>

      7: /*@
      8:   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`

     10:   Collective

     12:   Input Parameters:
     13: + da - the `DMDA`
     14: . x  - the first physical coordinate
     15: . y  - the second physical coordinate
     16: - z  - the third physical coordinate

     18:   Output Parameters:
     19: + II - the first logical coordinate (-1 on processes that do not contain that point)
     20: . JJ - the second logical coordinate (-1 on processes that do not contain that point)
     21: . KK - the third logical coordinate (-1 on processes that do not contain that point)
     22: . X  - (optional) the first coordinate of the located grid point
     23: . Y  - (optional) the second coordinate of the located grid point
     24: - Z  - (optional) the third coordinate of the located grid point

     26:   Level: advanced

     28:   Note:
     29:   All processors that share the `DMDA` must call this with the same coordinate value

     31: .seealso: [](sec_struct), `DM`, `DMDA`
     32: @*/
     33: PetscErrorCode DMDAGetLogicalCoordinate(DM da, PetscScalar x, PetscScalar y, PetscScalar z, PetscInt *II, PetscInt *JJ, PetscInt *KK, PetscScalar *X, PetscScalar *Y, PetscScalar *Z)
     34: {
     35:   Vec          coors;
     36:   DM           dacoors;
     37:   DMDACoor2d **c;
     38:   PetscInt     i, j, xs, xm, ys, ym;
     39:   PetscReal    d, D = PETSC_MAX_REAL, Dv;
     40:   PetscMPIInt  rank, root;

     42:   PetscFunctionBegin;
     43:   PetscCheck(da->dim != 1, PetscObjectComm((PetscObject)da), PETSC_ERR_SUP, "Cannot get point from 1d DMDA");
     44:   PetscCheck(da->dim != 3, PetscObjectComm((PetscObject)da), PETSC_ERR_SUP, "Cannot get point from 3d DMDA");

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

     49:   PetscCall(DMGetCoordinateDM(da, &dacoors));
     50:   PetscCall(DMDAGetCorners(dacoors, &xs, &ys, NULL, &xm, &ym, NULL));
     51:   PetscCall(DMGetCoordinates(da, &coors));
     52:   PetscCall(DMDAVecGetArrayRead(dacoors, coors, &c));
     53:   for (j = ys; j < ys + ym; j++) {
     54:     for (i = xs; i < xs + xm; i++) {
     55:       d = PetscSqrtReal(PetscRealPart((c[j][i].x - x) * (c[j][i].x - x) + (c[j][i].y - y) * (c[j][i].y - y)));
     56:       if (d < D) {
     57:         D   = d;
     58:         *II = i;
     59:         *JJ = j;
     60:       }
     61:     }
     62:   }
     63:   PetscCallMPI(MPIU_Allreduce(&D, &Dv, 1, MPIU_REAL, MPIU_MIN, PetscObjectComm((PetscObject)da)));
     64:   if (D != Dv) {
     65:     *II  = -1;
     66:     *JJ  = -1;
     67:     rank = 0;
     68:   } else {
     69:     *X = c[*JJ][*II].x;
     70:     *Y = c[*JJ][*II].y;
     71:     PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)da), &rank));
     72:     rank++;
     73:   }
     74:   PetscCallMPI(MPIU_Allreduce(&rank, &root, 1, MPI_INT, MPI_SUM, PetscObjectComm((PetscObject)da)));
     75:   root--;
     76:   PetscCallMPI(MPI_Bcast(X, 1, MPIU_SCALAR, root, PetscObjectComm((PetscObject)da)));
     77:   PetscCallMPI(MPI_Bcast(Y, 1, MPIU_SCALAR, root, PetscObjectComm((PetscObject)da)));
     78:   PetscCall(DMDAVecRestoreArrayRead(dacoors, coors, &c));
     79:   PetscFunctionReturn(PETSC_SUCCESS);
     80: }

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

     85:   Collective

     87:   Input Parameters:
     88: + da  - the `DMDA`
     89: . dir - Cartesian direction, either `DM_X`, `DM_Y`, or `DM_Z`
     90: - gp  - global grid point number in this direction

     92:   Output Parameters:
     93: + newvec  - the new vector that can hold the values (size zero on all processes except MPI rank 0)
     94: - scatter - the `VecScatter` that will map from the original vector to the ray

     96:   Level: advanced

     98:   Note:
     99:   All processors that share the `DMDA` must call this with the same `gp` value

    101: .seealso: [](sec_struct), `DM`, `DMDA`, `DMDirection`, `Vec`, `VecScatter`
    102: @*/
    103: PetscErrorCode DMDAGetRay(DM da, DMDirection dir, PetscInt gp, Vec *newvec, VecScatter *scatter)
    104: {
    105:   PetscMPIInt rank;
    106:   DM_DA      *dd = (DM_DA *)da->data;
    107:   IS          is;
    108:   AO          ao;
    109:   Vec         vec;
    110:   PetscInt   *indices, i, j;

    112:   PetscFunctionBegin;
    113:   PetscCheck(da->dim != 3, PetscObjectComm((PetscObject)da), PETSC_ERR_SUP, "Cannot get slice from 3d DMDA");
    114:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)da), &rank));
    115:   PetscCall(DMDAGetAO(da, &ao));
    116:   if (rank == 0) {
    117:     if (da->dim == 1) {
    118:       if (dir == DM_X) {
    119:         PetscCall(PetscMalloc1(dd->w, &indices));
    120:         indices[0] = dd->w * gp;
    121:         for (i = 1; i < dd->w; ++i) indices[i] = indices[i - 1] + 1;
    122:         PetscCall(AOApplicationToPetsc(ao, dd->w, indices));
    123:         PetscCall(VecCreate(PETSC_COMM_SELF, newvec));
    124:         PetscCall(VecSetBlockSize(*newvec, dd->w));
    125:         PetscCall(VecSetSizes(*newvec, dd->w, PETSC_DETERMINE));
    126:         PetscCall(VecSetType(*newvec, VECSEQ));
    127:         PetscCall(ISCreateGeneral(PETSC_COMM_SELF, dd->w, indices, PETSC_OWN_POINTER, &is));
    128:       } else {
    129:         PetscCheck(dir != DM_Y, PetscObjectComm((PetscObject)da), PETSC_ERR_SUP, "Cannot get Y slice from 1d DMDA");
    130:         SETERRQ(PetscObjectComm((PetscObject)da), PETSC_ERR_ARG_OUTOFRANGE, "Unknown DMDirection");
    131:       }
    132:     } else {
    133:       if (dir == DM_Y) {
    134:         PetscCall(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:         PetscCall(AOApplicationToPetsc(ao, dd->M * dd->w, indices));
    139:         PetscCall(VecCreate(PETSC_COMM_SELF, newvec));
    140:         PetscCall(VecSetBlockSize(*newvec, dd->w));
    141:         PetscCall(VecSetSizes(*newvec, dd->M * dd->w, PETSC_DETERMINE));
    142:         PetscCall(VecSetType(*newvec, VECSEQ));
    143:         PetscCall(ISCreateGeneral(PETSC_COMM_SELF, dd->w * dd->M, indices, PETSC_OWN_POINTER, &is));
    144:       } else if (dir == DM_X) {
    145:         PetscCall(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:         PetscCall(AOApplicationToPetsc(ao, dd->w * dd->N, indices));
    153:         PetscCall(VecCreate(PETSC_COMM_SELF, newvec));
    154:         PetscCall(VecSetBlockSize(*newvec, dd->w));
    155:         PetscCall(VecSetSizes(*newvec, dd->N * dd->w, PETSC_DETERMINE));
    156:         PetscCall(VecSetType(*newvec, VECSEQ));
    157:         PetscCall(ISCreateGeneral(PETSC_COMM_SELF, dd->w * dd->N, indices, PETSC_OWN_POINTER, &is));
    158:       } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Unknown DMDirection");
    159:     }
    160:   } else {
    161:     PetscCall(VecCreateSeq(PETSC_COMM_SELF, 0, newvec));
    162:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 0, NULL, PETSC_COPY_VALUES, &is));
    163:   }
    164:   PetscCall(DMGetGlobalVector(da, &vec));
    165:   PetscCall(VecScatterCreate(vec, is, *newvec, NULL, scatter));
    166:   PetscCall(DMRestoreGlobalVector(da, &vec));
    167:   PetscCall(ISDestroy(&is));
    168:   PetscFunctionReturn(PETSC_SUCCESS);
    169: }

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

    176:   Collective; No Fortran Support

    178:   Input Parameters:
    179: + da  - the `DMDA`
    180: . dir - Cartesian direction, either `DM_X`, `DM_Y`, or `DM_Z`
    181: - gp  - global grid point number in this direction

    183:   Output Parameter:
    184: . comm - new communicator

    186:   Level: advanced

    188:   Notes:
    189:   All processors that share the `DMDA` must call this with the same `gp` value

    191:   After use, `comm` should be freed with `MPI_Comm_free()`

    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: .seealso: [](sec_struct), `DM`, `DMDA`, `DMDirection`, `DM_X`, `DM_Y`, `DM_Z`, `DMDAGetProcessorSubsets()`
    198: @*/
    199: PetscErrorCode DMDAGetProcessorSubset(DM da, DMDirection dir, PetscInt gp, MPI_Comm *comm)
    200: {
    201:   MPI_Group   group, subgroup;
    202:   PetscMPIInt ict;
    203:   PetscInt    flag, *owners, xs, xm, ys, ym, zs, zm;
    204:   PetscMPIInt size, *ranks = NULL;
    205:   DM_DA      *dd = (DM_DA *)da->data;

    207:   PetscFunctionBegin;
    209:   flag = 0;
    210:   PetscCall(DMDAGetCorners(da, &xs, &ys, &zs, &xm, &ym, &zm));
    211:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)da), &size));
    212:   if (dir == DM_Z) {
    213:     PetscCheck(da->dim >= 3, PetscObjectComm((PetscObject)da), PETSC_ERR_ARG_OUTOFRANGE, "DM_Z invalid for DMDA dim < 3");
    214:     PetscCheck(gp >= 0 && gp <= dd->P, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "invalid grid point");
    215:     if (gp >= zs && gp < zs + zm) flag = 1;
    216:   } else if (dir == DM_Y) {
    217:     PetscCheck(da->dim != 1, PetscObjectComm((PetscObject)da), PETSC_ERR_ARG_OUTOFRANGE, "DM_Y invalid for DMDA dim = 1");
    218:     PetscCheck(gp >= 0 && gp <= dd->N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "invalid grid point");
    219:     if (gp >= ys && gp < ys + ym) flag = 1;
    220:   } else if (dir == DM_X) {
    221:     PetscCheck(gp >= 0 && gp <= dd->M, 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:   PetscCall(PetscMalloc2(size, &owners, size, &ranks));
    226:   PetscCallMPI(MPI_Allgather(&flag, 1, MPIU_INT, owners, 1, MPIU_INT, PetscObjectComm((PetscObject)da)));
    227:   ict = 0;
    228:   PetscCall(PetscInfo(da, "DMDAGetProcessorSubset: dim=%" PetscInt_FMT ", direction=%d, procs: ", da->dim, (int)dir)); /* checkbadSource \n */
    229:   for (PetscMPIInt i = 0; i < size; i++) {
    230:     if (owners[i]) {
    231:       ranks[ict] = i;
    232:       ict++;
    233:       PetscCall(PetscInfo(da, "%d", i)); /* checkbadSource \n */
    234:     }
    235:   }
    236:   PetscCall(PetscInfo(da, "\n"));
    237:   PetscCallMPI(MPI_Comm_group(PetscObjectComm((PetscObject)da), &group));
    238:   PetscCallMPI(MPI_Group_incl(group, ict, ranks, &subgroup));
    239:   PetscCallMPI(MPI_Comm_create(PetscObjectComm((PetscObject)da), subgroup, comm));
    240:   PetscCallMPI(MPI_Group_free(&subgroup));
    241:   PetscCallMPI(MPI_Group_free(&group));
    242:   PetscCall(PetscFree2(owners, ranks));
    243:   PetscFunctionReturn(PETSC_SUCCESS);
    244: }

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

    251:   Collective; No Fortran Support

    253:   Input Parameters:
    254: + da  - the `DMDA`
    255: - dir - Cartesian direction, either `DM_X`, `DM_Y`, or `DM_Z`

    257:   Output Parameter:
    258: . subcomm - new communicator

    260:   Level: advanced

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

    265:   After use, `comm` should be freed with `MPI_Comm_free()`

    267: .seealso: [](sec_struct), `DM`, `DMDA`, `DMDirection`, `DMDAGetProcessorSubset()`, `DM_X`, `DM_Y`, `DM_Z`
    268: @*/
    269: PetscErrorCode DMDAGetProcessorSubsets(DM da, DMDirection dir, MPI_Comm *subcomm)
    270: {
    271:   MPI_Comm    comm;
    272:   MPI_Group   group, subgroup;
    273:   PetscMPIInt subgroupSize = 0;
    274:   PetscInt   *firstPoints;
    275:   PetscMPIInt size, *subgroupRanks = NULL;
    276:   PetscInt    xs, xm, ys, ym, zs, zm, firstPoint;

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

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