petsc-3.13.6 2020-09-29

ISAllGather

Given an index set (IS) on each processor, generates a large index set (same on each processor) by concatenating together each processors index set.

Synopsis

#include "petscis.h"  
PetscErrorCode  ISAllGather(IS is,IS *isout)

Collective on IS

Input Parameter

is -the distributed index set

Output Parameter

isout -the concatenated index set (same on all processors)

Notes

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 itself.

The communicator for this new IS is PETSC_COMM_SELF

Level

intermediate

Location

src/vec/is/is/utils/iscoloring.c
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages