#![deny(warnings)]
extern crate mpi;
use mpi::traits::*;
use mpi::topology::Rank;
use mpi::collective::SystemOperation;
fn fac(n: Rank) -> Rank {
(1..n + 1).fold(1, |x, y| x * y)
}
fn main() {
let universe = mpi::initialize().unwrap();
let world = universe.world();
let rank = world.rank();
let mut x = 0;
mpi::request::scope(|scope| {
world.immediate_scan_into(scope, &rank, &mut x, SystemOperation::sum()).wait();
});
assert_eq!(x, (rank * (rank + 1)) / 2);
let y = rank + 1;
let mut z = 0;
mpi::request::scope(|scope| {
world.immediate_exclusive_scan_into(scope, &y, &mut z, SystemOperation::product()).wait();
});
if rank > 0 {
assert_eq!(z, fac(y - 1));
}
}