scan/
scan.rs

1#![deny(warnings)]
2extern crate mpi_fork_fnsp as mpi;
3
4use mpi::collective::SystemOperation;
5use mpi::topology::Rank;
6use mpi::traits::*;
7
8fn fac(n: Rank) -> Rank {
9    (1..=n).product()
10}
11
12fn main() {
13    let universe = mpi::initialize().unwrap();
14    let world = universe.world();
15    let rank = world.rank();
16
17    let mut x = 0;
18    world.scan_into(&rank, &mut x, &SystemOperation::sum());
19    assert_eq!(x, (rank * (rank + 1)) / 2);
20
21    let y = rank + 1;
22    let mut z = 0;
23    world.exclusive_scan_into(&y, &mut z, &SystemOperation::product());
24    if rank > 0 {
25        assert_eq!(z, fac(y - 1));
26    }
27}