/*@C
ISGetNonlocalIndices - Retrieve an array of indices from remote processors
in this communicator.
Collective on IS
Input Parameter:
. is - the index set
Output Parameter:
. indices - indices with rank 0 indices first, and so on, omitting
the current rank. Total number of indices is the difference
total and local, obtained with ISGetSize() and ISGetLocalSize(),
respectively.
Level: intermediate
Notes: restore the indices using ISRestoreNonlocalIndices().
The same scalability considerations as those for ISGetTotalIndices
apply here.
Concepts: index sets^getting nonlocal indices
.seealso: ISGetTotalIndices(), ISRestoreNonlocalIndices(), ISGetSize(), ISGetLocalSize().
@*/
PetscErrorCode ISGetNonlocalIndices(IS is, const PetscInt *indices[])
{
PetscErrorCode ierr;
PetscMPIInt size;
PetscInt n, N;
PetscFunctionBegin;
PetscValidHeaderSpecific(is,IS_CLASSID,1);
PetscValidPointer(indices,2);
ierr = MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
CHKERRQ(ierr);
if (size == 1) *indices = NULL;
else {
if (!is->total) {
ierr = ISGatherTotal_Private(is);
CHKERRQ(ierr);
}
ierr = ISGetLocalSize(is,&n);
CHKERRQ(ierr);
ierr = ISGetSize(is,&N);
CHKERRQ(ierr);
ierr = PetscMalloc(sizeof(PetscInt)*(N-n), &(is->nonlocal));
CHKERRQ(ierr);
ierr = PetscMemcpy(is->nonlocal, is->total, sizeof(PetscInt)*is->local_offset);
CHKERRQ(ierr);
ierr = PetscMemcpy(is->nonlocal+is->local_offset, is->total+is->local_offset+n, sizeof(PetscInt)*(N - is->local_offset - n));
CHKERRQ(ierr);
*indices = is->nonlocal;
}
PetscFunctionReturn(0);
}
/*@C
ISGetTotalIndices - Retrieve an array containing all indices across the communicator.
Collective on IS
Input Parameter:
. is - the index set
Output Parameter:
. indices - total indices with rank 0 indices first, and so on; total array size is
the same as returned with ISGetSize().
Level: intermediate
Notes: this is potentially nonscalable, but depends on the size of the total index set
and the size of the communicator. This may be feasible for index sets defined on
subcommunicators, such that the set size does not grow with PETSC_WORLD_COMM.
Note also that there is no way to tell where the local part of the indices starts
(use ISGetIndices() and ISGetNonlocalIndices() to retrieve just the local and just
the nonlocal part (complement), respectively).
Concepts: index sets^getting nonlocal indices
.seealso: ISRestoreTotalIndices(), ISGetNonlocalIndices(), ISGetSize()
@*/
PetscErrorCode ISGetTotalIndices(IS is, const PetscInt *indices[])
{
PetscErrorCode ierr;
PetscMPIInt size;
PetscFunctionBegin;
PetscValidHeaderSpecific(is,IS_CLASSID,1);
PetscValidPointer(indices,2);
ierr = MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);CHKERRQ(ierr);
if (size == 1) {
ierr = (*is->ops->getindices)(is,indices);CHKERRQ(ierr);
} else {
if (!is->total) {
ierr = ISGatherTotal_Private(is);CHKERRQ(ierr);
}
*indices = is->total;
}
PetscFunctionReturn(0);
}
