petsc-3.7.7 2017-09-25

DMCreate

Creates an empty DM object. The type can then be set with DMSetType().

#include "petscdm.h"          
#include "petscdmlabel.h"     
PetscErrorCode  DMCreate(MPI_Comm comm,DM *dm)

If you never call DMSetType() it will generate an error when you try to use the vector.

Collective on MPI_Comm

comm -The communicator for the DM object

dm -The DM object