ISDifference#
Computes the difference between two index sets.
Synopsis#
#include "petscis.h"
PetscErrorCode ISDifference(IS is1, IS is2, IS *isout)
Collective
Input Parameters#
is1 - first index, to have items removed from it
is2 - index values to be removed
Output Parameter#
isout - is1 - is2
Notes#
Negative values are removed from the lists. is2 may have values
that are not in is1.
This computation requires O(imax-imin) memory and O(imax-imin) work, where imin and imax are the bounds on the indices in is1.
If is2 is NULL, the result is the same as for an empty IS, i.e., a duplicate of is1.
The difference is computed separately on each MPI rank
See Also#
Low-level Vector Communication, IS, ISDestroy(), ISView(), ISSum(), ISExpand()
Level#
intermediate
Location#
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages