DMPlexBuildFromCellListParallel#

Build a distributed DMPLEX topology from a list of vertices for each cell (common mesh generator output) where all cells have the same celltype

Synopsis#

#include "petscdmplex.h"   
#include "petscdmplextransform.h"   
PetscErrorCode DMPlexBuildFromCellListParallel(DM dm, PetscInt numCells, PetscInt numVertices, PetscInt NVertices, PetscInt numCorners, const PetscInt cells[], PeOp PetscSF *vertexSF, PeOp PetscInt *verticesAdjSaved[])

Collective; No Fortran Support

Input Parameters#

dm - The DM
numCells - The number of cells owned by this process
numVertices - The number of vertices to be owned by this process, or PETSC_DECIDE
NVertices - The global number of vertices, or PETSC_DETERMINE
numCorners - The number of vertices for each cell
cells - An array of \(numCells \times numCorners\) numbers, the global vertex numbers for each cell

Output Parameters#

vertexSF - (Optional) PetscSF describing complete vertex ownership
verticesAdjSaved - (Optional) List of unique vertices in cells, must be freed by user

Notes#

Two triangles sharing a face

        2
      / | \
     /  |  \
    /   |   \
   0  0 | 1  3
    \   |   /
     \  |  /
      \ | /
        1

would have input

  numCells = 2, numVertices = 4
  cells = [0 1 2  1 3 2]

which would result in the DMPLEX

        4
      / | \
     /  |  \
    /   |   \
   2  0 | 1  5
    \   |   /
     \  |  /
      \ | /
        3

During the process of building the DMPlex, PETSc uses PetscLayout to have an “initial” partitioning of the global vertex numbers across ranks. The vertices are implicitly numbered consecutively \(0, \ldots, \mathrm{NVertices} - 1\). Each rank owns a non-overlapping chunk of numVertices consecutive vertices in rank order.

If numVertices is PETSC_DECIDE, PETSc will distribute them as evenly as possible using PetscLayout. If NVertices is PETSC_DETERMINE and numVertices is PETSC_DECIDE, NVertices is computed by PETSc as the maximum vertex index in \(cells + 1\). If only NVertices is PETSC_DETERMINE, it is computed as the sum of numVertices over all ranks.

vertexSF is the mapping between the PetscLayout of global vertex points to the overlapping vertex distribution of the assembled Plex.

The cell distribution is arbitrary non-overlapping and based on each rank’s cell-vertex connectivity in cells. It is completely independent of the vertex PetscLayout used.

Level#

advanced

Location#

src/dm/impls/plex/plexcreate.c

Examples#

src/dm/impls/plex/tests/ex47.c

Index of all DMPlex routines
Table of Contents for all manual pages
Index of all manual pages