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//! Integration test for Win::create and Win::allocate (distributed RMA windows).
//!
//! Verifies that `Win<T>` can be constructed via both constructors, that
//! `raw_handle()` and `comm_size()` return expected values, and that the RAII
//! `Drop` implementation does not produce MPI errors.
//!
//! Run with: mpiexec -n 2 ./target/debug/examples/test_rma_win_create
use ferrompi::{Mpi, Win};
fn main() {
let mpi = Mpi::init().expect("MPI init failed");
let world = mpi.world();
let rank = world.rank();
let size = world.size();
assert!(
size >= 2,
"test_rma_win_create requires at least 2 processes, got {size}"
);
// ========================================================================
// Probe: Win::create and Win::allocate require MPI >= 3.
// Check the MPI version and skip gracefully on older implementations.
// ========================================================================
let version_str = Mpi::version().unwrap_or_default();
// version_str is like "MPI 3.1" or "MPI 4.0"
let major: u32 = version_str
.split_whitespace()
.nth(1)
.and_then(|v| v.split('.').next())
.and_then(|m| m.parse().ok())
.unwrap_or(0);
if major < 3 {
if rank == 0 {
println!("SKIP: Win::create and Win::allocate require MPI >= 3 (got {version_str})");
}
return;
}
// ========================================================================
// Test 1: Win::create with a caller-supplied i32 buffer
//
// OpenMPI 4.x with `--btl=self,tcp` (the configuration used in CI when
// UCX/rdma is not available) does not provide a one-sided communication
// transport that supports `MPI_Win_create` over caller-owned memory.
// The call returns `MPI_ERR_WIN` ("invalid window") on those builds,
// even though the arguments are valid by the MPI standard.
// `MPI_Win_allocate` (Test 2 below) uses MPI-managed memory and is
// supported. Skip Test 1 gracefully when this OpenMPI-CI quirk fires.
// ========================================================================
let mut buf = vec![0i32; 16];
let test1_skipped = {
match Win::create(&world, &mut buf) {
Ok(win) => {
let handle = win.raw_handle();
assert!(
handle >= 0,
"Win::create raw_handle() = {handle}, expected >= 0"
);
let cs = win.comm_size();
assert_eq!(cs, size, "Win::create comm_size() mismatch");
// Verify local_slice / local_slice_mut round-trip
let slice = win.local_slice();
assert_eq!(slice.len(), 16, "Win::create local_slice len mismatch");
// Win dropped at end of arm — exercises MPI_Win_free for
// WinKind::Created.
drop(win);
false
}
Err(ferrompi::Error::Mpi {
class: ferrompi::MpiErrorClass::Win,
..
}) => {
if rank == 0 {
println!(
"SKIP: Win::create returned MPI_ERR_WIN — likely OpenMPI 4.x \
with a BTL that does not support one-sided over caller-owned \
memory (e.g., --btl=self,tcp in CI). Win::allocate (Test 2) \
still tested."
);
}
true
}
Err(e) => panic!("Win::create failed: {e}"),
}
};
world.barrier().expect("barrier after test 1 failed");
if rank == 0 && !test1_skipped {
println!("PASS: Win::create (i32, 16 elements, raw_handle, comm_size, local_slice)");
}
// ========================================================================
// Test 2: Win::allocate with MPI-managed memory
// ========================================================================
{
let local_count: usize = 32;
let mut win = Win::<f64>::allocate(&world, local_count).expect("Win::allocate failed");
let handle = win.raw_handle();
assert!(
handle >= 0,
"Win::allocate raw_handle() = {handle}, expected >= 0"
);
let cs = win.comm_size();
assert_eq!(cs, size, "Win::allocate comm_size() mismatch");
// Verify local_slice_mut write-then-read round-trip
{
let slice = win.local_slice_mut();
assert_eq!(
slice.len(),
local_count,
"Win::allocate local_slice_mut len mismatch"
);
for (i, x) in slice.iter_mut().enumerate() {
*x = (rank as f64) * 100.0 + i as f64;
}
}
// Read back via local_slice
{
let slice = win.local_slice();
for (i, &x) in slice.iter().enumerate() {
let expected = (rank as f64) * 100.0 + i as f64;
assert!(
(x - expected).abs() < f64::EPSILON,
"Win::allocate local_slice[{i}] = {x}, expected {expected}"
);
}
}
// Win dropped here — exercises MPI_Win_free for WinKind::Allocated
}
world.barrier().expect("barrier after test 2 failed");
if rank == 0 {
println!("PASS: Win::allocate (f64, 32 elements, raw_handle, comm_size, local_slice_mut, local_slice)");
}
world.barrier().expect("final barrier failed");
if rank == 0 {
println!("\n========================================");
println!("All Win create/allocate tests passed! (2 tests)");
println!("========================================");
}
}