1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
//! Integration test for `CustomDatatype::create_struct`.
//!
//! Exercises:
//! - Successful construction of a `{ f64, i32 }` struct type (8-byte f64 at
//! offset 0, i32 at offset 8) and `raw_handle() >= 0`
//! - Indexed-basetype rejection returns `Error::InvalidOp` before any FFI call
//! - Empty `fields` slice returns an MPI error (implementation-defined class:
//! `MpiErrorClass::Arg` or `MpiErrorClass::Count` are both accepted)
//! - Drop frees the underlying MPI handle (no double-free on exit)
//!
//! All assertions are protected by a sentinel allreduce(Min) before any
//! `process::exit` call so that no rank exits while others are still inside MPI.
//!
//! Run with: mpiexec -n 2 ./target/debug/examples/test_custom_dt_struct
use ferrompi::{CustomDatatype, DatatypeTag, Error, Mpi, MpiErrorClass, ReduceOp, StructField};
fn main() {
let mpi = Mpi::init().expect("MPI init failed");
let world = mpi.world();
let rank = world.rank();
// local_ok tracks whether this rank passed all its assertions.
let mut local_ok = true;
// ========================================================================
// Test 1: create_struct for a { f64, i32 } layout returns Ok with
// raw_handle() >= 0
// ========================================================================
{
let fields = [
StructField {
blocklength: 1,
displacement: 0,
basetype: DatatypeTag::F64,
},
StructField {
blocklength: 1,
displacement: 8,
basetype: DatatypeTag::I32,
},
];
match CustomDatatype::create_struct(&fields) {
Ok(s) => {
let h = s.raw_handle();
if h >= 0 {
if rank == 0 {
println!("PASS: Test 1 — create_struct({{f64,i32}}) raw_handle = {h}");
}
} else {
eprintln!("rank {rank}: FAIL Test 1 — raw_handle = {h}, expected >= 0");
local_ok = false;
}
// s drops here, freeing the MPI handle
}
Err(e) => {
eprintln!(
"rank {rank}: FAIL Test 1 — create_struct({{f64,i32}}) returned Err: {e}"
);
local_ok = false;
}
}
}
// ========================================================================
// Test 2: create_struct with a FloatInt field returns Err(Error::InvalidOp)
// without calling into MPI (pre-FFI validation in the Rust wrapper)
// ========================================================================
{
let fields = [StructField {
blocklength: 1,
displacement: 0,
basetype: DatatypeTag::FloatInt,
}];
match CustomDatatype::create_struct(&fields) {
Err(Error::InvalidOp) => {
if rank == 0 {
println!(
"PASS: Test 2 — create_struct(FloatInt field) returned Err(InvalidOp)"
);
}
}
other => {
eprintln!(
"rank {rank}: FAIL Test 2 — expected Err(InvalidOp), got: {:?}",
other.err()
);
local_ok = false;
}
}
}
// ========================================================================
// Test 3: create_struct(&[]) returns an Err or a zero-size type.
//
// MPI_Type_create_struct with count=0 is rejected by most implementations
// with MPI_ERR_ARG or MPI_ERR_COUNT (both accepted). However, some
// implementations (e.g. Open MPI >= 5.0) accept count=0 and produce a
// valid zero-size datatype — this is also accepted as conforming.
// The C shim forwards count=0 directly to MPI (no early return) so the
// exact outcome is implementation-defined.
// ========================================================================
{
match CustomDatatype::create_struct(&[]) {
Err(Error::Mpi { class, .. }) => {
let accepted = matches!(class, MpiErrorClass::Arg | MpiErrorClass::Count);
if accepted {
if rank == 0 {
println!(
"PASS: Test 3 — create_struct(&[]) returned Err({class:?}) \
(implementation-defined Arg or Count)"
);
}
} else {
// Some MPI implementations may return other error classes
// for count=0. Accept any MPI error as conforming.
if rank == 0 {
println!(
"NOTE: Test 3 — create_struct(&[]) returned Err({class:?}) \
(non-standard class, still an error — accepted)"
);
}
}
}
Err(e) => {
// Any error is acceptable for an empty slice.
if rank == 0 {
println!("PASS: Test 3 — create_struct(&[]) returned Err: {e}");
}
}
Ok(s) => {
// Some MPI implementations accept count=0 and produce a valid
// zero-size datatype. This is conforming; accept it with a note.
if rank == 0 {
println!(
"NOTE: Test 3 — create_struct(&[]) succeeded (raw_handle={}) — \
MPI implementation accepts count=0 (conforming)",
s.raw_handle()
);
}
}
}
}
// ========================================================================
// Sentinel allreduce: every rank must reach this point.
// Reduces local_ok across all ranks so that any per-rank failure causes
// the whole job to exit non-zero.
// ========================================================================
let local_flag: i32 = if local_ok { 1 } else { 0 };
let global_flag = match world.allreduce_scalar(local_flag, ReduceOp::Min) {
Ok(v) => v,
Err(e) => {
eprintln!("rank {rank}: sentinel allreduce failed: {e}");
std::process::exit(1);
}
};
if global_flag == 0 {
if rank == 0 {
eprintln!("FAIL: one or more ranks reported a test failure");
}
std::process::exit(1);
}
if rank == 0 {
println!("\n========================================");
println!("All custom datatype struct tests passed!");
println!("========================================");
}
}