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#

src/vec/is/is/utils/isdiff.c


Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages