コード例 #1
0
static PetscErrorCode DMPlexGetVTKConnectivity(DM dm,PieceInfo *piece,PetscVTKInt **oconn,PetscVTKInt **ooffsets,PetscVTKType **otypes)
{
  PetscErrorCode ierr;
  PetscVTKInt    *conn,*offsets;
  PetscVTKType   *types;
  PetscInt       dim,vStart,vEnd,cStart,cEnd,pStart,pEnd,cellHeight,cMax,numLabelCells,hasLabel,c,v,countcell,countconn;

  PetscFunctionBegin;
  ierr = PetscMalloc3(piece->nconn,PetscVTKInt,&conn,piece->ncells,PetscVTKInt,&offsets,piece->ncells,PetscVTKType,&types);CHKERRQ(ierr);

  ierr = DMPlexGetDimension(dm,&dim);CHKERRQ(ierr);
  ierr = DMPlexGetChart(dm,&pStart,&pEnd);CHKERRQ(ierr);
  ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
  ierr = DMPlexGetHeightStratum(dm, cellHeight, &cStart, &cEnd);CHKERRQ(ierr);
  ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
  ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
  if (cMax >= 0) cEnd = PetscMin(cEnd, cMax);
  ierr     = DMPlexGetStratumSize(dm, "vtk", 1, &numLabelCells);CHKERRQ(ierr);
  hasLabel = numLabelCells > 0 ? PETSC_TRUE : PETSC_FALSE;

  countcell = 0;
  countconn = 0;
  for (c = cStart; c < cEnd; ++c) {
    PetscInt *closure = NULL;
    PetscInt  closureSize,nverts,celltype,startoffset,nC=0;

    if (hasLabel) {
      PetscInt value;

      ierr = DMPlexGetLabelValue(dm, "vtk", c, &value);CHKERRQ(ierr);
      if (value != 1) continue;
    }
    startoffset = countconn;
    ierr        = DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    for (v = 0; v < closureSize*2; v += 2) {
      if ((closure[v] >= vStart) && (closure[v] < vEnd)) {
        conn[countconn++] = closure[v] - vStart;
        ++nC;
      }
    }
    ierr = DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    ierr = DMPlexInvertCell(dim, nC, &conn[countconn-nC]);CHKERRQ(ierr);

    offsets[countcell] = countconn;

    nverts = countconn - startoffset;
    ierr   = DMPlexVTKGetCellType(dm,dim,nverts,&celltype);CHKERRQ(ierr);

    types[countcell] = celltype;
    countcell++;
  }
  if (countcell != piece->ncells) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Inconsistent cell count");
  if (countconn != piece->nconn) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Inconsistent connectivity count");
  *oconn    = conn;
  *ooffsets = offsets;
  *otypes   = types;
  PetscFunctionReturn(0);
}
コード例 #2
0
ファイル: plexvtk.c プロジェクト: pombredanne/petsc
PetscErrorCode DMPlexVTKWritePartition_ASCII(DM dm, FILE *fp)
{
  MPI_Comm       comm;
  PetscInt       numCells = 0, cellHeight;
  PetscInt       numLabelCells, cMax, cStart, cEnd, c;
  PetscMPIInt    numProcs, rank, proc, tag;
  PetscBool      hasLabel;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
  ierr = PetscCommGetNewTag(comm, &tag);CHKERRQ(ierr);
  ierr = MPI_Comm_size(comm, &numProcs);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
  ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
  ierr = DMPlexGetHeightStratum(dm, cellHeight, &cStart, &cEnd);CHKERRQ(ierr);
  ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
  if (cMax >= 0) cEnd = PetscMin(cEnd, cMax);
  ierr = DMPlexGetStratumSize(dm, "vtk", 1, &numLabelCells);CHKERRQ(ierr);
  hasLabel = numLabelCells > 0 ? PETSC_TRUE : PETSC_FALSE;
  for (c = cStart; c < cEnd; ++c) {
    if (hasLabel) {
      PetscInt value;

      ierr = DMPlexGetLabelValue(dm, "vtk", c, &value);CHKERRQ(ierr);
      if (value != 1) continue;
    }
    ++numCells;
  }
  if (!rank) {
    for (c = 0; c < numCells; ++c) {ierr = PetscFPrintf(comm, fp, "%d\n", rank);CHKERRQ(ierr);}
    for (proc = 1; proc < numProcs; ++proc) {
      MPI_Status status;

      ierr = MPI_Recv(&numCells, 1, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      for (c = 0; c < numCells; ++c) {ierr = PetscFPrintf(comm, fp, "%d\n", proc);CHKERRQ(ierr);}
    }
  } else {
    ierr = MPI_Send(&numCells, 1, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}
コード例 #3
0
ファイル: plexvtk.c プロジェクト: pombredanne/petsc
PetscErrorCode DMPlexVTKWriteCells_ASCII(DM dm, FILE *fp, PetscInt *totalCells)
{
  MPI_Comm       comm;
  DMLabel        label;
  IS             globalVertexNumbers = NULL;
  const PetscInt *gvertex;
  PetscInt       dim;
  PetscInt       numCorners = 0, totCorners = 0, maxCorners, *corners;
  PetscInt       numCells   = 0, totCells   = 0, maxCells, cellHeight;
  PetscInt       numLabelCells, maxLabelCells, cMax, cStart, cEnd, c, vStart, vEnd, v;
  PetscMPIInt    numProcs, rank, proc, tag;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
  ierr = PetscCommGetNewTag(comm, &tag);CHKERRQ(ierr);
  ierr = MPI_Comm_size(comm, &numProcs);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
  ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
  ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
  ierr = DMPlexGetHeightStratum(dm, cellHeight, &cStart, &cEnd);CHKERRQ(ierr);
  ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
  ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
  if (cMax >= 0) cEnd = PetscMin(cEnd, cMax);
  ierr = DMPlexGetLabel(dm, "vtk", &label);CHKERRQ(ierr);
  ierr = DMPlexGetStratumSize(dm, "vtk", 1, &numLabelCells);CHKERRQ(ierr);
  ierr = MPI_Allreduce(&numLabelCells, &maxLabelCells, 1, MPIU_INT, MPI_MAX, comm);CHKERRQ(ierr);
  if (!maxLabelCells) label = NULL;
  for (c = cStart; c < cEnd; ++c) {
    PetscInt *closure = NULL;
    PetscInt closureSize, value;

    if (label) {
      ierr = DMLabelGetValue(label, c, &value);CHKERRQ(ierr);
      if (value != 1) continue;
    }
    ierr = DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    for (v = 0; v < closureSize*2; v += 2) {
      if ((closure[v] >= vStart) && (closure[v] < vEnd)) ++numCorners;
    }
    ierr = DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    ++numCells;
  }
  maxCells = numCells;
  ierr     = MPI_Reduce(&numCells, &totCells, 1, MPIU_INT, MPI_SUM, 0, comm);CHKERRQ(ierr);
  ierr     = MPI_Reduce(&numCells, &maxCells, 1, MPIU_INT, MPI_MAX, 0, comm);CHKERRQ(ierr);
  ierr     = MPI_Reduce(&numCorners, &totCorners, 1, MPIU_INT, MPI_SUM, 0, comm);CHKERRQ(ierr);
  ierr     = MPI_Reduce(&numCorners, &maxCorners, 1, MPIU_INT, MPI_MAX, 0, comm);CHKERRQ(ierr);
  ierr     = DMPlexGetVertexNumbering(dm, &globalVertexNumbers);CHKERRQ(ierr);
  ierr     = ISGetIndices(globalVertexNumbers, &gvertex);CHKERRQ(ierr);
  ierr     = PetscMalloc1(maxCells, &corners);CHKERRQ(ierr);
  ierr     = PetscFPrintf(comm, fp, "CELLS %d %d\n", totCells, totCorners+totCells);CHKERRQ(ierr);
  if (!rank) {
    PetscInt *remoteVertices;
    int      *vertices;

    ierr = PetscMalloc1(maxCorners, &vertices);CHKERRQ(ierr);
    for (c = cStart, numCells = 0; c < cEnd; ++c) {
      PetscInt *closure = NULL;
      PetscInt closureSize, value, nC = 0;

      if (label) {
        ierr = DMLabelGetValue(label, c, &value);CHKERRQ(ierr);
        if (value != 1) continue;
      }
      ierr = DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
      for (v = 0; v < closureSize*2; v += 2) {
        if ((closure[v] >= vStart) && (closure[v] < vEnd)) {
          const PetscInt gv = gvertex[closure[v] - vStart];
          vertices[nC++] = gv < 0 ? -(gv+1) : gv;
        }
      }
      ierr = DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
      corners[numCells++] = nC;
      ierr = PetscFPrintf(comm, fp, "%d ", nC);CHKERRQ(ierr);
      ierr = DMPlexInvertCell(dim, nC, vertices);CHKERRQ(ierr);
      for (v = 0; v < nC; ++v) {
        ierr = PetscFPrintf(comm, fp, " %d", vertices[v]);CHKERRQ(ierr);
      }
      ierr = PetscFPrintf(comm, fp, "\n");CHKERRQ(ierr);
    }
    if (numProcs > 1) {ierr = PetscMalloc1(maxCorners+maxCells, &remoteVertices);CHKERRQ(ierr);}
    for (proc = 1; proc < numProcs; ++proc) {
      MPI_Status status;

      ierr = MPI_Recv(&numCorners, 1, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      ierr = MPI_Recv(remoteVertices, numCorners, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      for (c = 0; c < numCorners;) {
        PetscInt nC = remoteVertices[c++];

        for (v = 0; v < nC; ++v, ++c) {
          vertices[v] = remoteVertices[c];
        }
        ierr = DMPlexInvertCell(dim, nC, vertices);CHKERRQ(ierr);
        ierr = PetscFPrintf(comm, fp, "%d ", nC);CHKERRQ(ierr);
        for (v = 0; v < nC; ++v) {
          ierr = PetscFPrintf(comm, fp, " %d", vertices[v]);CHKERRQ(ierr);
        }
        ierr = PetscFPrintf(comm, fp, "\n");CHKERRQ(ierr);
      }
    }
    if (numProcs > 1) {ierr = PetscFree(remoteVertices);CHKERRQ(ierr);}
    ierr = PetscFree(vertices);CHKERRQ(ierr);
  } else {
    PetscInt *localVertices, numSend = numCells+numCorners, k = 0;

    ierr = PetscMalloc1(numSend, &localVertices);CHKERRQ(ierr);
    for (c = cStart, numCells = 0; c < cEnd; ++c) {
      PetscInt *closure = NULL;
      PetscInt closureSize, value, nC = 0;

      if (label) {
        ierr = DMLabelGetValue(label, c, &value);CHKERRQ(ierr);
        if (value != 1) continue;
      }
      ierr = DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
      for (v = 0; v < closureSize*2; v += 2) {
        if ((closure[v] >= vStart) && (closure[v] < vEnd)) {
          const PetscInt gv = gvertex[closure[v] - vStart];
          closure[nC++] = gv < 0 ? -(gv+1) : gv;
        }
      }
      corners[numCells++] = nC;
      localVertices[k++]  = nC;
      for (v = 0; v < nC; ++v, ++k) {
        localVertices[k] = closure[v];
      }
      ierr = DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    }
    if (k != numSend) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB, "Invalid number of vertices to send %d should be %d", k, numSend);
    ierr = MPI_Send(&numSend, 1, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
    ierr = MPI_Send(localVertices, numSend, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
    ierr = PetscFree(localVertices);CHKERRQ(ierr);
  }
  ierr = ISRestoreIndices(globalVertexNumbers, &gvertex);CHKERRQ(ierr);
  ierr = PetscFPrintf(comm, fp, "CELL_TYPES %d\n", totCells);CHKERRQ(ierr);
  if (!rank) {
    PetscInt cellType;

    for (c = 0; c < numCells; ++c) {
      ierr = DMPlexVTKGetCellType(dm, dim, corners[c], &cellType);CHKERRQ(ierr);
      ierr = PetscFPrintf(comm, fp, "%d\n", cellType);CHKERRQ(ierr);
    }
    for (proc = 1; proc < numProcs; ++proc) {
      MPI_Status status;

      ierr = MPI_Recv(&numCells, 1, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      ierr = MPI_Recv(corners, numCells, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      for (c = 0; c < numCells; ++c) {
        ierr = DMPlexVTKGetCellType(dm, dim, corners[c], &cellType);CHKERRQ(ierr);
        ierr = PetscFPrintf(comm, fp, "%d\n", cellType);CHKERRQ(ierr);
      }
    }
  } else {
    ierr = MPI_Send(&numCells, 1, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
    ierr = MPI_Send(corners, numCells, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
  }
  ierr        = PetscFree(corners);CHKERRQ(ierr);
  *totalCells = totCells;
  PetscFunctionReturn(0);
}
コード例 #4
0
ファイル: plexvtk.c プロジェクト: pombredanne/petsc
PetscErrorCode DMPlexVTKWriteSection_ASCII(DM dm, PetscSection section, PetscSection globalSection, Vec v, FILE *fp, PetscInt enforceDof, PetscInt precision, PetscReal scale)
{
  MPI_Comm           comm;
  const MPI_Datatype mpiType = MPIU_SCALAR;
  PetscScalar        *array;
  PetscInt           numDof = 0, maxDof;
  PetscInt           numLabelCells, cellHeight, cMax, cStart, cEnd, numLabelVertices, vMax, vStart, vEnd, pStart, pEnd, p;
  PetscMPIInt        numProcs, rank, proc, tag;
  PetscBool          hasLabel;
  PetscErrorCode     ierr;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  PetscValidHeaderSpecific(v,VEC_CLASSID,4);
  if (precision < 0) precision = 6;
  ierr = PetscCommGetNewTag(comm, &tag);CHKERRQ(ierr);
  ierr = MPI_Comm_size(comm, &numProcs);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(comm, &rank);CHKERRQ(ierr);
  ierr = PetscSectionGetChart(section, &pStart, &pEnd);CHKERRQ(ierr);
  /* VTK only wants the values at cells or vertices */
  ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
  ierr = DMPlexGetHeightStratum(dm, cellHeight, &cStart, &cEnd);CHKERRQ(ierr);
  ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
  ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, &vMax);CHKERRQ(ierr);
  if (cMax >= 0) cEnd = PetscMin(cEnd, cMax);
  if (vMax >= 0) vEnd = PetscMin(vEnd, vMax);
  pStart   = PetscMax(PetscMin(cStart, vStart), pStart);
  pEnd     = PetscMin(PetscMax(cEnd,   vEnd),   pEnd);
  ierr     = DMPlexGetStratumSize(dm, "vtk", 1, &numLabelCells);CHKERRQ(ierr);
  ierr     = DMPlexGetStratumSize(dm, "vtk", 2, &numLabelVertices);CHKERRQ(ierr);
  hasLabel = numLabelCells > 0 || numLabelVertices > 0 ? PETSC_TRUE : PETSC_FALSE;
  for (p = pStart; p < pEnd; ++p) {
    /* Reject points not either cells or vertices */
    if (((p < cStart) || (p >= cEnd)) && ((p < vStart) || (p >= vEnd))) continue;
    if (hasLabel) {
      PetscInt value;

      if (((p >= cStart) && (p < cEnd) && numLabelCells) ||
          ((p >= vStart) && (p < vEnd) && numLabelVertices)) {
        ierr = DMPlexGetLabelValue(dm, "vtk", p, &value);CHKERRQ(ierr);
        if (value != 1) continue;
      }
    }
    ierr = PetscSectionGetDof(section, p, &numDof);CHKERRQ(ierr);
    if (numDof) break;
  }
  ierr = MPI_Allreduce(&numDof, &maxDof, 1, MPIU_INT, MPI_MAX, comm);CHKERRQ(ierr);
  enforceDof = PetscMax(enforceDof, maxDof);
  ierr = VecGetArray(v, &array);CHKERRQ(ierr);
  if (!rank) {
    char formatString[8];

    ierr = PetscSNPrintf(formatString, 8, "%%.%de", precision);CHKERRQ(ierr);
    for (p = pStart; p < pEnd; ++p) {
      /* Here we lose a way to filter points by keeping them out of the Numbering */
      PetscInt dof, off, goff, d;

      /* Reject points not either cells or vertices */
      if (((p < cStart) || (p >= cEnd)) && ((p < vStart) || (p >= vEnd))) continue;
      if (hasLabel) {
        PetscInt value;

        if (((p >= cStart) && (p < cEnd) && numLabelCells) ||
            ((p >= vStart) && (p < vEnd) && numLabelVertices)) {
          ierr = DMPlexGetLabelValue(dm, "vtk", p, &value);CHKERRQ(ierr);
          if (value != 1) continue;
        }
      }
      ierr = PetscSectionGetDof(section, p, &dof);CHKERRQ(ierr);
      ierr = PetscSectionGetOffset(section, p, &off);CHKERRQ(ierr);
      ierr = PetscSectionGetOffset(globalSection, p, &goff);CHKERRQ(ierr);
      if (dof && goff >= 0) {
        for (d = 0; d < dof; d++) {
          if (d > 0) {
            ierr = PetscFPrintf(comm, fp, " ");CHKERRQ(ierr);
          }
          ierr = PetscFPrintf(comm, fp, formatString, PetscRealPart(array[off+d])*scale);CHKERRQ(ierr);
        }
        for (d = dof; d < enforceDof; d++) {
          ierr = PetscFPrintf(comm, fp, " 0.0");CHKERRQ(ierr);
        }
        ierr = PetscFPrintf(comm, fp, "\n");CHKERRQ(ierr);
      }
    }
    for (proc = 1; proc < numProcs; ++proc) {
      PetscScalar *remoteValues;
      PetscInt    size = 0, d;
      MPI_Status  status;

      ierr = MPI_Recv(&size, 1, MPIU_INT, proc, tag, comm, &status);CHKERRQ(ierr);
      ierr = PetscMalloc1(size, &remoteValues);CHKERRQ(ierr);
      ierr = MPI_Recv(remoteValues, size, mpiType, proc, tag, comm, &status);CHKERRQ(ierr);
      for (p = 0; p < size/maxDof; ++p) {
        for (d = 0; d < maxDof; ++d) {
          if (d > 0) {
            ierr = PetscFPrintf(comm, fp, " ");CHKERRQ(ierr);
          }
          ierr = PetscFPrintf(comm, fp, formatString, PetscRealPart(remoteValues[p*maxDof+d])*scale);CHKERRQ(ierr);
        }
        for (d = maxDof; d < enforceDof; ++d) {
          ierr = PetscFPrintf(comm, fp, " 0.0");CHKERRQ(ierr);
        }
        ierr = PetscFPrintf(comm, fp, "\n");CHKERRQ(ierr);
      }
      ierr = PetscFree(remoteValues);CHKERRQ(ierr);
    }
  } else {
    PetscScalar *localValues;
    PetscInt    size, k = 0;

    ierr = PetscSectionGetStorageSize(section, &size);CHKERRQ(ierr);
    ierr = PetscMalloc1(size, &localValues);CHKERRQ(ierr);
    for (p = pStart; p < pEnd; ++p) {
      PetscInt dof, off, goff, d;

      /* Reject points not either cells or vertices */
      if (((p < cStart) || (p >= cEnd)) && ((p < vStart) || (p >= vEnd))) continue;
      if (hasLabel) {
        PetscInt value;

        if (((p >= cStart) && (p < cEnd) && numLabelCells) ||
            ((p >= vStart) && (p < vEnd) && numLabelVertices)) {
          ierr = DMPlexGetLabelValue(dm, "vtk", p, &value);CHKERRQ(ierr);
          if (value != 1) continue;
        }
      }
      ierr = PetscSectionGetDof(section, p, &dof);CHKERRQ(ierr);
      ierr = PetscSectionGetOffset(section, p, &off);CHKERRQ(ierr);
      ierr = PetscSectionGetOffset(globalSection, p, &goff);CHKERRQ(ierr);
      if (goff >= 0) {
        for (d = 0; d < dof; ++d) {
          localValues[k++] = array[off+d];
        }
      }
    }
    ierr = MPI_Send(&k, 1, MPIU_INT, 0, tag, comm);CHKERRQ(ierr);
    ierr = MPI_Send(localValues, k, mpiType, 0, tag, comm);CHKERRQ(ierr);
    ierr = PetscFree(localValues);CHKERRQ(ierr);
  }
  ierr = VecRestoreArray(v, &array);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
コード例 #5
0
/*
  Write all fields that have been provided to the viewer
  Multi-block XML format with binary appended data.
*/
PetscErrorCode DMPlexVTKWriteAll_VTU(DM dm,PetscViewer viewer)
{
  MPI_Comm                 comm;
  PetscViewer_VTK          *vtk = (PetscViewer_VTK*)viewer->data;
  PetscViewerVTKObjectLink link;
  FILE                     *fp;
  PetscMPIInt              rank,size,tag;
  PetscErrorCode           ierr;
  PetscInt                 dim,cellHeight,cStart,cEnd,vStart,vEnd,cMax,numLabelCells,hasLabel,c,v,r,i;
  PieceInfo                piece,*gpiece = NULL;
  void                     *buffer = NULL;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject)dm,&comm);CHKERRQ(ierr);
#if defined(PETSC_USE_COMPLEX)
  SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Complex values not supported");
#endif
  ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
  tag  = ((PetscObject)viewer)->tag;

  ierr = PetscFOpen(comm,vtk->filename,"wb",&fp);CHKERRQ(ierr);
  ierr = PetscFPrintf(comm,fp,"<?xml version=\"1.0\"?>\n");CHKERRQ(ierr);
#if defined(PETSC_WORDS_BIGENDIAN)
  ierr = PetscFPrintf(comm,fp,"<VTKFile type=\"UnstructuredGrid\" version=\"0.1\" byte_order=\"BigEndian\">\n");CHKERRQ(ierr);
#else
  ierr = PetscFPrintf(comm,fp,"<VTKFile type=\"UnstructuredGrid\" version=\"0.1\" byte_order=\"LittleEndian\">\n");CHKERRQ(ierr);
#endif
  ierr = PetscFPrintf(comm,fp,"  <UnstructuredGrid>\n");CHKERRQ(ierr);

  ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
  ierr = DMPlexGetVTKCellHeight(dm, &cellHeight);CHKERRQ(ierr);
  ierr = DMPlexGetHeightStratum(dm, cellHeight, &cStart, &cEnd);CHKERRQ(ierr);
  ierr = DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd);CHKERRQ(ierr);
  ierr = DMPlexGetHybridBounds(dm, &cMax, NULL, NULL, NULL);CHKERRQ(ierr);
  if (cMax >= 0) cEnd = PetscMin(cEnd, cMax);
  ierr = DMPlexGetStratumSize(dm, "vtk", 1, &numLabelCells);CHKERRQ(ierr);

  hasLabel        = numLabelCells > 0 ? PETSC_TRUE : PETSC_FALSE;
  piece.nvertices = vEnd - vStart;
  piece.ncells    = 0;
  piece.nconn     = 0;
  for (c = cStart; c < cEnd; ++c) {
    PetscInt *closure = NULL;
    PetscInt closureSize;

    if (hasLabel) {
      PetscInt value;

      ierr = DMPlexGetLabelValue(dm, "vtk", c, &value);CHKERRQ(ierr);
      if (value != 1) continue;
    }
    ierr = DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    for (v = 0; v < closureSize*2; v += 2) {
      if ((closure[v] >= vStart) && (closure[v] < vEnd)) piece.nconn++;
    }
    ierr = DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure);CHKERRQ(ierr);
    piece.ncells++;
  }
  if (!rank) {ierr = PetscMalloc(size*sizeof(piece),&gpiece);CHKERRQ(ierr);}
  ierr = MPI_Gather((PetscInt*)&piece,sizeof(piece)/sizeof(PetscInt),MPIU_INT,(PetscInt*)gpiece,sizeof(piece)/sizeof(PetscInt),MPIU_INT,0,comm);CHKERRQ(ierr);

  /*
   * Write file header
   */
  if (!rank) {
    PetscInt boffset = 0;

    for (r=0; r<size; r++) {
      ierr = PetscFPrintf(PETSC_COMM_SELF,fp,"    <Piece NumberOfPoints=\"%D\" NumberOfCells=\"%D\">\n",gpiece[r].nvertices,gpiece[r].ncells);CHKERRQ(ierr);
      /* Coordinate positions */
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"      <Points>\n");CHKERRQ(ierr);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"        <DataArray type=\"%s\" Name=\"Position\" NumberOfComponents=\"3\" format=\"appended\" offset=\"%D\" />\n",precision,boffset);CHKERRQ(ierr);
      boffset += gpiece[r].nvertices*3*sizeof(PetscScalar) + sizeof(int);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"      </Points>\n");CHKERRQ(ierr);
      /* Cell connectivity */
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"      <Cells>\n");CHKERRQ(ierr);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"        <DataArray type=\"Int32\" Name=\"connectivity\" NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",boffset);CHKERRQ(ierr);
      boffset += gpiece[r].nconn*sizeof(PetscInt) + sizeof(int);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"        <DataArray type=\"Int32\" Name=\"offsets\"      NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",boffset);CHKERRQ(ierr);
      boffset += gpiece[r].ncells*sizeof(PetscInt) + sizeof(int);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"        <DataArray type=\"UInt8\" Name=\"types\"        NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",boffset);CHKERRQ(ierr);
      boffset += gpiece[r].ncells*sizeof(unsigned char) + sizeof(int);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"      </Cells>\n");CHKERRQ(ierr);

      /*
       * Cell Data headers
       */
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"      <CellData>\n");CHKERRQ(ierr);
      ierr     = PetscFPrintf(PETSC_COMM_SELF,fp,"        <DataArray type=\"Int32\" Name=\"Rank\" NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",boffset);CHKERRQ(ierr);
      boffset += gpiece[r].ncells*sizeof(int) + sizeof(int);
      /* all the vectors */
      for (link=vtk->link; link; link=link->next) {
        Vec        X = (Vec)link->vec;
        PetscInt   bs,nfields,field;
        const char *vecname = "";
        if ((link->ft != PETSC_VTK_CELL_FIELD) && (link->ft != PETSC_VTK_CELL_VECTOR_FIELD)) continue;
        if (((PetscObject)X)->name || link != vtk->link) { /* If the object is already named, use it. If it is past the first link, name it to disambiguate. */
          ierr = PetscObjectGetName((PetscObject)X,&vecname);CHKERRQ(ierr);
        }
        ierr = PetscSectionGetDof(dm->defaultSection,cStart,&bs);CHKERRQ(ierr);
        ierr = PetscSectionGetNumFields(dm->defaultSection,&nfields);CHKERRQ(ierr);
        for (field=0,i=0; field<(nfields?nfields:1); field++) {
          PetscInt   fbs,j;
          const char *fieldname = NULL;
          char       buf[256];
          if (nfields) {        /* We have user-defined fields/components */
            ierr = PetscSectionGetFieldDof(dm->defaultSection,cStart,field,&fbs);CHKERRQ(ierr);
            ierr = PetscSectionGetFieldName(dm->defaultSection,field,&fieldname);CHKERRQ(ierr);
          } else fbs = bs;      /* Say we have one field with 'bs' components */
          if (!fieldname) {
            ierr = PetscSNPrintf(buf,sizeof(buf),"CellField%D",field);CHKERRQ(ierr);
            fieldname = buf;
          }
          for (j=0; j<fbs; j++) {
            ierr = PetscFPrintf(comm,fp,"        <DataArray type=\"%s\" Name=\"%s%s.%D\" NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",precision,vecname,fieldname,j,boffset);CHKERRQ(ierr);
            boffset += gpiece[r].ncells*sizeof(PetscScalar) + sizeof(int);
            i++;
          }
        }
        if (i != bs) SETERRQ2(comm,PETSC_ERR_PLIB,"Total number of field components %D != block size %D",i,bs);
      }
      ierr = PetscFPrintf(PETSC_COMM_SELF,fp,"      </CellData>\n");CHKERRQ(ierr);

      /*
       * Point Data headers
       */
      ierr = PetscFPrintf(PETSC_COMM_SELF,fp,"      <PointData>\n");CHKERRQ(ierr);
      for (link=vtk->link; link; link=link->next) {
        Vec        X = (Vec)link->vec;
        PetscInt   bs,nfields,field;
        const char *vecname = "";
        if ((link->ft != PETSC_VTK_POINT_FIELD) && (link->ft != PETSC_VTK_POINT_VECTOR_FIELD)) continue;
        if (((PetscObject)X)->name || link != vtk->link) { /* If the object is already named, use it. If it is past the first link, name it to disambiguate. */
          ierr = PetscObjectGetName((PetscObject)X,&vecname);CHKERRQ(ierr);
        }
        ierr = PetscSectionGetDof(dm->defaultSection,vStart,&bs);CHKERRQ(ierr);
        ierr = PetscSectionGetNumFields(dm->defaultSection,&nfields);CHKERRQ(ierr);
        for (field=0,i=0; field<(nfields?nfields:1); field++) {
          PetscInt   fbs,j;
          const char *fieldname = NULL;
          char       buf[256];
          if (nfields) {        /* We have user-defined fields/components */
            ierr = PetscSectionGetFieldDof(dm->defaultSection,vStart,field,&fbs);CHKERRQ(ierr);
            ierr = PetscSectionGetFieldName(dm->defaultSection,field,&fieldname);CHKERRQ(ierr);
          } else fbs = bs;      /* Say we have one field with 'bs' components */
          if (!fieldname) {
            ierr = PetscSNPrintf(buf,sizeof(buf),"PointField%D",field);CHKERRQ(ierr);
            fieldname = buf;
          }
          for (j=0; j<fbs; j++) {
            ierr = PetscFPrintf(comm,fp,"        <DataArray type=\"%s\" Name=\"%s%s.%D\" NumberOfComponents=\"1\" format=\"appended\" offset=\"%D\" />\n",precision,vecname,fieldname,j,boffset);CHKERRQ(ierr);
            boffset += gpiece[r].nvertices*sizeof(PetscScalar) + sizeof(int);
          }
        }
      }
      ierr = PetscFPrintf(PETSC_COMM_SELF,fp,"      </PointData>\n");CHKERRQ(ierr);

      ierr = PetscFPrintf(PETSC_COMM_SELF,fp,"    </Piece>\n");CHKERRQ(ierr);
    }
  }

  ierr = PetscFPrintf(comm,fp,"  </UnstructuredGrid>\n");CHKERRQ(ierr);
  ierr = PetscFPrintf(comm,fp,"  <AppendedData encoding=\"raw\">\n");CHKERRQ(ierr);
  ierr = PetscFPrintf(comm,fp,"_");CHKERRQ(ierr);

  if (!rank) {
    PetscInt maxsize = 0;
    for (r=0; r<size; r++) {
      maxsize = PetscMax(maxsize, (PetscInt) (gpiece[r].nvertices*3*sizeof(PetscScalar)));
      maxsize = PetscMax(maxsize, (PetscInt) (gpiece[r].ncells*sizeof(PetscScalar)));
      maxsize = PetscMax(maxsize, (PetscInt) (gpiece[r].nconn*sizeof(PetscVTKInt)));
    }
    ierr = PetscMalloc(maxsize,&buffer);CHKERRQ(ierr);
  }
  for (r=0; r<size; r++) {
    if (r == rank) {
      PetscInt nsend;
      {                         /* Position */
        const PetscScalar *x;
        PetscScalar       *y = NULL;
        Vec               coords;
        nsend = piece.nvertices*3;
        ierr  = DMGetCoordinatesLocal(dm,&coords);CHKERRQ(ierr);
        ierr  = VecGetArrayRead(coords,&x);CHKERRQ(ierr);
        if (dim != 3) {
          ierr = PetscMalloc(piece.nvertices*3*sizeof(PetscScalar),&y);CHKERRQ(ierr);
          for (i=0; i<piece.nvertices; i++) {
            y[i*3+0] = x[i*dim+0];
            y[i*3+1] = (dim > 1) ? x[i*dim+1] : 0;
            y[i*3+2] = 0;
          }
        }
        ierr = TransferWrite(viewer,fp,r,0,y ? y : x,buffer,nsend,PETSC_SCALAR,tag);CHKERRQ(ierr);
        ierr = PetscFree(y);CHKERRQ(ierr);
        ierr = VecRestoreArrayRead(coords,&x);CHKERRQ(ierr);
      }
      {                           /* Connectivity, offsets, types */
        PetscVTKInt  *connectivity = NULL,*offsets;
        PetscVTKType *types;
        ierr = DMPlexGetVTKConnectivity(dm,&piece,&connectivity,&offsets,&types);CHKERRQ(ierr);
        ierr = TransferWrite(viewer,fp,r,0,connectivity,buffer,piece.nconn,PETSC_INT32,tag);CHKERRQ(ierr);
        ierr = TransferWrite(viewer,fp,r,0,offsets,buffer,piece.ncells,PETSC_INT32,tag);CHKERRQ(ierr);
        ierr = TransferWrite(viewer,fp,r,0,types,buffer,piece.ncells,PETSC_UINT8,tag);CHKERRQ(ierr);
        ierr = PetscFree3(connectivity,offsets,types);CHKERRQ(ierr);
      }
      {                         /* Owners (cell data) */
        PetscVTKInt *owners;
        ierr = PetscMalloc(piece.ncells*sizeof(PetscVTKInt),&owners);CHKERRQ(ierr);
        for (i=0; i<piece.ncells; i++) owners[i] = rank;
        ierr = TransferWrite(viewer,fp,r,0,owners,buffer,piece.ncells,PETSC_INT32,tag);CHKERRQ(ierr);
        ierr = PetscFree(owners);CHKERRQ(ierr);
      }
      /* Cell data */
      for (link=vtk->link; link; link=link->next) {
        Vec               X = (Vec)link->vec;
        const PetscScalar *x;
        PetscScalar       *y;
        PetscInt          bs;
        if ((link->ft != PETSC_VTK_CELL_FIELD) && (link->ft != PETSC_VTK_CELL_VECTOR_FIELD)) continue;
        ierr = PetscSectionGetDof(dm->defaultSection,cStart,&bs);CHKERRQ(ierr);
        ierr = VecGetArrayRead(X,&x);CHKERRQ(ierr);
        ierr = PetscMalloc(piece.ncells*sizeof(PetscScalar),&y);CHKERRQ(ierr);
        for (i=0; i<bs; i++) {
          PetscInt cnt;
          for (c=cStart,cnt=0; c<cEnd; c++) {
            const PetscScalar *xpoint;
            if (hasLabel) {     /* Ignore some cells */
              PetscInt value;
              ierr = DMPlexGetLabelValue(dm, "vtk", c, &value);CHKERRQ(ierr);
              if (value != 1) continue;
            }
            ierr     = DMPlexPointLocalRead(dm,c,x,&xpoint);CHKERRQ(ierr);
            y[cnt++] = xpoint[i];
          }
          if (cnt != piece.ncells) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Count does not match");
          ierr = TransferWrite(viewer,fp,r,0,y,buffer,piece.ncells,PETSC_SCALAR,tag);CHKERRQ(ierr);
        }
        ierr = PetscFree(y);CHKERRQ(ierr);
        ierr = VecRestoreArrayRead(X,&x);CHKERRQ(ierr);
      }

      for (link=vtk->link; link; link=link->next) {
        Vec               X = (Vec)link->vec;
        const PetscScalar *x;
        PetscScalar       *y;
        PetscInt          bs;
        if ((link->ft != PETSC_VTK_POINT_FIELD) && (link->ft != PETSC_VTK_POINT_VECTOR_FIELD)) continue;
        ierr = PetscSectionGetDof(dm->defaultSection,vStart,&bs);CHKERRQ(ierr);
        ierr = VecGetArrayRead(X,&x);CHKERRQ(ierr);
        ierr = PetscMalloc(piece.nvertices*sizeof(PetscScalar),&y);CHKERRQ(ierr);
        for (i=0; i<bs; i++) {
          PetscInt cnt;
          for (v=vStart,cnt=0; v<vEnd; v++) {
            const PetscScalar *xpoint;
            ierr     = DMPlexPointLocalRead(dm,v,x,&xpoint);CHKERRQ(ierr);
            y[cnt++] = xpoint[i];
          }
          if (cnt != piece.nvertices) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Count does not match");
          ierr = TransferWrite(viewer,fp,r,0,y,buffer,piece.nvertices,PETSC_SCALAR,tag);CHKERRQ(ierr);
        }
        ierr = PetscFree(y);CHKERRQ(ierr);
        ierr = VecRestoreArrayRead(X,&x);CHKERRQ(ierr);
      }
    } else if (!rank) {
      ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].nvertices*3,PETSC_SCALAR,tag);CHKERRQ(ierr); /* positions */
      ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].nconn,PETSC_INT32,tag);CHKERRQ(ierr); /* connectivity */
      ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].ncells,PETSC_INT32,tag);CHKERRQ(ierr); /* offsets */
      ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].ncells,PETSC_UINT8,tag);CHKERRQ(ierr); /* types */
      ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].ncells,PETSC_INT32,tag);CHKERRQ(ierr); /* owner rank (cells) */
      /* all cell data */
      for (link=vtk->link; link; link=link->next) {
        PetscInt bs;
        if ((link->ft != PETSC_VTK_CELL_FIELD) && (link->ft != PETSC_VTK_CELL_VECTOR_FIELD)) continue;
        ierr = PetscSectionGetDof(dm->defaultSection,cStart,&bs);CHKERRQ(ierr);
        for (i=0; i<bs; i++) {
          ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].ncells,PETSC_SCALAR,tag);CHKERRQ(ierr);
        }
      }
      /* all point data */
      for (link=vtk->link; link; link=link->next) {
        PetscInt bs;
        if ((link->ft != PETSC_VTK_POINT_FIELD) && (link->ft != PETSC_VTK_POINT_VECTOR_FIELD)) continue;
        ierr = PetscSectionGetDof(dm->defaultSection,vStart,&bs);CHKERRQ(ierr);
        for (i=0; i<bs; i++) {
          ierr = TransferWrite(viewer,fp,r,0,NULL,buffer,gpiece[r].nvertices,PETSC_SCALAR,tag);CHKERRQ(ierr);
        }
      }
    }
  }
  ierr = PetscFree(gpiece);CHKERRQ(ierr);
  ierr = PetscFree(buffer);CHKERRQ(ierr);
  ierr = PetscFPrintf(comm,fp,"\n  </AppendedData>\n");CHKERRQ(ierr);
  ierr = PetscFPrintf(comm,fp,"</VTKFile>\n");CHKERRQ(ierr);
  PetscFunctionReturn(0);
}