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
Input Parameters#
- is1 - first index set 
- is2 - second index set 
Output Parameter#
- isout - the sorted intersection of - is1and- 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
is1 and is2 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