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

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

See Also#

Low-level Vector Communication, IS, ISCreateGeneral(), ISCreateStride(), ISCreateBlock()

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