Crate mpi 

mpi-rs — a pure-Rust Message Passing Interface

This crate (published as mpi-rs, imported as mpi) is a from-scratch, pure-Rust implementation of MPI whose public API mirrors rsmpi (the mpi crate) so that existing rsmpi programs compile and run against it with little or no change. Unlike rsmpi, it does not link against a C MPI library (Open MPI / MPICH): the runtime — process bootstrap, the byte transport, and every collective algorithm — is implemented here in safe Rust on top of the standard library only (the default build has zero external dependencies).

Quick start

use mpi::traits::*;

let universe = mpi::initialize().unwrap();
let world = universe.world();
let size = world.size();
let rank = world.rank();

if rank == 0 {
    let msg = [1.0f64, 2.0, 3.0];
    world.process_at_rank(1).send(&msg[..]);
} else if rank == 1 {
    let (msg, status) = world.process_at_rank(0).receive_vec::<f64>();
    println!("rank 1 received {:?} (status {:?})", msg, status);
}

Run it with the bundled launcher:

mpiexec -n 4 ./target/debug/examples/hello

A program that is not launched under mpiexec runs as a singleton job (world size 1, rank 0), exactly like a C MPI singleton MPI_Init.

Re-exports

pub use environment::initialize;

pub use environment::initialize_with_threading;

pub use environment::library_version;

pub use environment::processor_name;

pub use environment::threading_support;

pub use environment::time;

pub use environment::time_resolution;

pub use environment::version;

pub use environment::Threading;

pub use environment::Universe;

Modules

attribute

Attribute caching on communicators. Mirrors rsmpi’s attribute module: a keyval identifies a slot, and arbitrary typed values can be cached on a communicator and retrieved later.

collective

Collective communication and reduction operations. Mirrors mpi::collective in rsmpi: the CommunicatorCollectives trait (rootless collectives, blanket-implemented for every Communicator), the Root trait (rooted collectives, implemented for Process), the Operation trait, and SystemOperation / UserOperation.

datatype

Datatypes and buffers.

environment

Process-wide MPI environment: initialization, finalization and the Universe handle. Mirrors mpi::environment in rsmpi.

error

Error classes and error handlers (MPI_Errhandler, MPI_ERR_*).

io

Parallel file I/O (File), corresponding to MPI’s I/O chapter (MPI_File_*), which released rsmpi does not currently expose.

launcher

The pure-Rust MPI process launcher, shared by the mpiexec and mpirun binaries.

point_to_point

Point-to-point communication. Mirrors mpi::point_to_point in rsmpi: the Source (receive) and Destination (send) traits, Status, Message (matched probe) and the send_receive free functions.

raw

Bridge between Rust types and their underlying raw handles. Mirrors mpi::raw in rsmpi. In a C-backed MPI these expose the opaque MPI_* handles; here the “raw” form of a handle is the pure-Rust identifier the runtime uses internally (e.g. a communicator context id).

request

Non-blocking request handling. Mirrors mpi::request in rsmpi: Request borrows the buffer involved in an in-flight operation for the lifetime of the request, Scope bounds that borrow, and WaitGuard / CancelGuard complete a request when they go out of scope.

topology

Groups and communicators. Mirrors mpi::topology in rsmpi (0.8.x), where the former SystemCommunicator/UserCommunicator split is unified into a single SimpleCommunicator. Backwards-compatible aliases for the old names are provided.

traits

Convenient re-export of every public trait, mirroring mpi::traits in rsmpi. The idiomatic import is:

window

One-sided (RMA) communication: Windows of memory that remote ranks can put into, get from, and accumulate into without the target making a matching call. This corresponds to MPI’s one-sided chapter (MPI_Win_*), which released rsmpi does not currently expose.

Enums

MpiError

Errors that can occur while managing the MPI environment.

Constants

ANY_SOURCE

A convenience re-export of the wildcard constants. Wildcard matching any source rank (MPI_ANY_SOURCE).

ANY_TAG

A convenience re-export of the wildcard constants. Wildcard matching any tag (MPI_ANY_TAG).

Type Aliases

Address

A byte displacement / absolute address (MPI_Aint).

Count

The integer type counting elements in a buffer (int in the C API).

Rank

The integer type used to identify a process within a communicator (MPI_Comm_rank).

Tag

The integer type used to tag point-to-point messages.

Derive Macros

Equivalence

Derive macro for datatype::Equivalence (enabled by the derive feature).