petsc3.10.4 20190226
ISCreateBlock
Creates a data structure for an index set containing a list of integers. The indices are relative to entries, not blocks.
Synopsis
#include "petscis.h"
PetscErrorCode ISCreateBlock(MPI_Comm comm,PetscInt bs,PetscInt n,const PetscInt idx[],PetscCopyMode mode,IS *is)
Collective on MPI_Comm
Input Parameters
 comm   the MPI communicator

 bs   number of elements in each block

 n   the length of the index set (the number of blocks)

 idx   the list of integers, one for each block and count of block not indices

 mode   see PetscCopyMode, only PETSC_COPY_VALUES and PETSC_OWN_POINTER are supported in this routine

Output Parameter
is the new index set
Notes
When the communicator is not MPI_COMM_SELF, the operations on the
index sets, IS, are NOT conceptually the same as MPI_Group operations.
The index sets are then distributed sets of indices and thus certain operations
on them are collective.
Example
If you wish to index the values {0,1,6,7}, then use
a block size of 2 and idx of {0,3}.
See Also
ISCreateStride(), ISCreateGeneral(), ISAllGather()
Level
beginner
Location
src/vec/is/is/impls/block/block.c
Examples
src/vec/vec/utils/tagger/examples/tutorials/ex1.c.html
src/vec/is/is/examples/tutorials/ex3.c.html
src/vec/is/is/examples/tutorials/ex3f90.F90.html
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages