PetscSplitOwnership

Given a global (or local) length determines a local (or global) length via a simple formula

Synopsis

#include "petscsys.h" 
PetscErrorCode PetscSplitOwnership(MPI_Comm comm, PetscInt *n, PetscInt *N)

Collective (if n or N is PETSC_DECIDE)

Input Parameters

• comm - MPI communicator that shares the object being divided

• n - local length (or PETSC_DECIDE to have it set)

• N - global length (or PETSC_DECIDE)

Notes

n and N cannot be both PETSC_DECIDE

If one processor calls this with n or N of PETSC_DECIDE then all processors must. Otherwise, an error is thrown in debug mode while the program will hang in optimized (i.e. configured –with-debugging=0) mode.

See Also

PetscSplitOwnershipBlock(), PetscSplitOwnershipEqual()

Level

developer

Location

src/sys/utils/psplit.c

Examples

src/ksp/ksp/tutorials/ex85.c
src/ksp/ksp/tutorials/bench_kspsolve.c

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