PETSc version 3.17.4
Given an index set (IS) on each processor, generates a large index set (same on each processor) by concatenating together each processors index set.
PetscErrorCode ISAllGather(IS is,IS *isout)
Collective on IS
|is ||- the distributed index set
|isout ||- the concatenated index set (same on all processors)
ISAllGather() is clearly not scalable for large index sets.
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
The communicator for this new IS is PETSC_COMM_SELF
ISCreateGeneral(), ISCreateStride(), ISCreateBlock()
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages