ISIntersect#
Computes the intersection of two index sets, by sorting and comparing.
Synopsis#
#include "petscis.h"
PetscErrorCode ISIntersect(IS is1, IS is2, IS *isout)
Collective on is1
Input Parameters#
is1 - first index set
is2 - second index set
Output Parameters#
isout - the sorted intersection of is1 and is2
Notes#
Negative values are removed from the lists. This requires O(min(is1,is2)) memory and O(max(is1,is2)log(max(is1,is2))) work
The IS’s do not need to be sorted.
The operations are performed separately on each MPI rank
See Also#
Low-level Vector Communication, IS
, ISDestroy()
, ISView()
, ISDifference()
, ISSum()
, ISExpand()
, ISConcatenate()
Level#
intermediate
Location#
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages