This package provides a Python script to parse and generate bindings for the Message Passing Interface (MPI) standard. The parser analyzes the MPI headers and generates a specification file with the defined macros, functions and types. The specification file is different for each version and implementation of MPI, which can be stored to generate bindings without using the parser.
As case studies, we can currently generate bindings for Java and Go. Java makes use of Foreign Linker API and Foreign Memory Access API so the performance is significantly better than Java Native Interface (JNI) implementations. Go use cgo, so MPI headers are needed to compile. More languages may be added in the future, so feel free to make a pull request.
The goal of the project is to create efficient bindings for MPI automatically. The project will never become an object oriented interface like mpi4py, although an equivalent library could be built using our bindings.
MPI4All has been built in the field of the IgnisHPC project for MPI usage.
I you use MPI4All, please cite:
César Piñeiro, Álvaro Vázquez and Juan C. Pichel. MPI4All: Universal Binding Generation for MPI Parallel Programming. 24th Int. Conference on Computational Science (ICCS). LNCS 14832, pp. 196–208, 2024.
You can install MPI4All using pip:
$ pip install mpi4all
- Python 3.9+
- An MPI Library
Tested with:
MPI4All can generate the bindings for Java and Go with the default MPI library installed in the system:
$ mpi4all --go --java
or using a specification file:
$ mpi4all --load mpich-4.0.json --go --java
Specification files can be generated with --dump or downloaded from the releases section.
External functions cannot use data inside java heap. The example shows how to use ByteBuffer.allocateDirect and Arena to allocate memory outside the java heap.
import java.lang.foreign.*;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import org.mpi.Mpi;
public class Main {
public static void main(String[] args) throws Throwable {
Mpi.MPI_Init(Mpi.C_pointer.NULL.cast(), Mpi.MPI_ARGVS_NULL);
int rank;
int size;
// When the buffer is interpreted by the MPI function, the native order must be used.
// If the MPI function only sends or receives the buffer, the order is indifferent.
ByteBuffer buffer = ByteBuffer.allocateDirect(Mpi.C_int.byteSize()).order(ByteOrder.nativeOrder());
Mpi.MPI_Comm_rank(Mpi.MPI_COMM_WORLD, new Mpi.C_pointer<>(MemorySegment.ofBuffer(buffer)));
rank = buffer.get(0);
try (Arena arena = Arena.ofConfined()) {// Using confined arena
Mpi.C_int c_size = Mpi.C_int.alloc(arena);
Mpi.MPI_Comm_size(Mpi.MPI_COMM_WORLD, c_size.pointer(arena));
size = c_size.get();
}
buffer = ByteBuffer.allocateDirect(Mpi.C_int.byteSize() * size);
Mpi.C_int c_rank = new Mpi.C_int(0); // Using auto gc arena
Mpi.MPI_Allgather(c_rank.pointer().cast(), 1, Mpi.MPI_INT,
new Mpi.C_pointer<>(MemorySegment.ofBuffer(buffer)), 1, Mpi.MPI_INT, Mpi.MPI_COMM_WORLD);
for (int i = 0; i < size; i++) {
if (i != buffer.get(i)) {
throw new RuntimeException("Allgather error");
}
}
Mpi.MPI_Finalize();
}
}C_int and int data types are usually aliases but it is preferable to use C_int to avoid surprises. Functions with void * arguments use usafe.pointer instead, you can use the auxiliary functions mpi.P and mpi.PA to convert variables and array respectively to usafe.pointer. All other pointers are converted to their equivalents in Go, &var or &array[0] is sufficient to send the memory address.
package main
import "mpi"
func main() {
if err := mpi.MPI_Init(nil, nil); err != nil {
panic(err)
}
var rank mpi.C_int
var size mpi.C_int
if err := mpi.MPI_Comm_rank(mpi.MPI_COMM_WORLD, &rank); err != nil {
panic(err)
}
if err := mpi.MPI_Comm_size(mpi.MPI_COMM_WORLD, &size); err != nil {
panic(err)
}
result := make([]mpi.C_int, int(size))
if err := mpi.MPI_Allgather(mpi.P(&rank), 1, mpi.MPI_INT,
mpi.PA(&result), mpi.C_int(len(result)), mpi.MPI_INT, mpi.MPI_COMM_WORLD); err != nil {
panic(err)
}
for i := 0; i < int(size); i++ {
if i != int(result[i]) {
panic("Allgather error")
}
}
if err := mpi.MPI_Finalize(); err != nil {
panic(err)
}
}usage: mpi4all [-h] [--out path] [--log lvl] [--cc path] [--cxx path]
[--exclude str [str ...]] [--enable-fortran] [--dump path]
[--load path] [--cache path] [--go] [--go-no-generic]
[--go-package name] [--go-out name] [--java] [--jdk21]
[--java-package name] [--java-class name] [--java-out name]
[--java-lib-name name] [--java-lib-out name] [--version]
Universal Binding Generation for MPI Parallel Programming
options:
-h, --help show this help message and exit
--out path, -o path Place output in folder, by default is working
directory
--log lvl Log level, default error
--version show program's version number and exit
Parser Arguments:
--cc path MPI C compiler, by default search in PATH
--cxx path MPI C++ compiler, by default search in PATH
--exclude str [str ...]
Exclude functions and macros that match with any
pattern
--enable-fortran Parse MPI Fortran functions, which are disabled by
default, to avoid linking errors if they are not
available
--dump path Save blueprint as json file, - for stdout
--load path Disable parser and load a blueprint, - for stdin
--cache path Make --dump if the blueprint does not exist and --load
otherwise
Go Generator Arguments:
--go Enable Go Generator
--go-no-generic Disable utility functions that require go 1.18+
--go-package name Go package name, default mpi
--go-out name Go output directory, by default <out>
Java Generator Arguments:
--java Enable Java Generator
--jdk21 Use JDK 21 preview instead of Java 22+ Generator
--java-package name Java package name, default org.mpi
--java-class name Java class name, default Mpi
--java-out name Java output directory, default <out>
--java-lib-name name Java native library name without any extension,
default mpi4all
--java-lib-out name Java output directory for C library, default <java-
out>/<java-lib-name>