#include "petscis.h" PetscErrorCode ISAllGather(IS is,IS *isout)Collective on IS
|is||- the distributed index set|
|isout||- the concatenated index set (same on all processors)|
The IS created on each processor must be created with a common communicator (e.g., PETSC_COMM_WORLD). If the index sets were created with PETSC_COMM_SELF, this routine will not work as expected, since each process will generate its own new IS that consists only of itself.
The communicator for this new IS is PETSC_COMM_SELF