the equivalent of the
MPI_COMM_WORLD communicator which represents all the processes that PETSc knows about.
MPI_COMM_WORLD are identical unless you wish to
run PETSc on ONLY a subset of
MPI_COMM_WORLD. In that case create your new (smaller)
communicator, call it, say comm, and set
PETSC_COMM_WORLD = comm BEFORE calling
PetscInitialize(), but after
MPI_Init() has been called.
The value of
PETSC_COMM_WORLD should never be USED/accessed before
is called because it may not have a valid value yet.
Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages