#include <petscsys.h> PetscErrorCode MPIU_Allreduce(void *indata,void *outdata,PetscMPIInt count,MPI_Datatype datatype, MPI_Op op, MPI_Comm comm);
| indata | - pointer to the input data to be reduced | |
| count | - the number of MPI data items in indata and outdata | |
| datatype | - the MPI datatype, for example MPI_INT | |
| op | - the MPI operation, for example MPI_SUM | |
| comm | - the MPI communicator on which the operation occurs |
| outdata | - the reduced values |