Java FFI based binding for MPI
- java 22
The MPI4J uses Java's Foreign Function Inferface. To run access it the application must be started with a corresponding command line options:
$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib64/openmpi/lib
$ $JAVA_HOME/bin/java --enable-native-access=ALL-UNNAMED -cp ... App
public static void main(String[] args) throws Throwable {
System.out.println("=== MPI4J ===");
MPI.mpiInit(args);
int myRank = MPI.world().mpiCommRank();
int size = MPI.world().mpiCommSize();
double[] out = new double[0];
if (myRank == 0) {
System.out.println("size: " + size);
out = new double[size];
}
MPI.world().mpiGather(ThreadLocalRandom.current().nextDouble(), out);
MPI.world().mpiBarrier();
if (myRank == 0) {
for (int i = 0; i < out.length; i++) {
System.out.println("out[" + i + "] = " + out[i]);
}
}
mpiFinalize();
}This project is a proof of concept and not expected to be used (at least now) for real application. Nevertheless, pull-requests are welcome!
With the provided stable automatic module name de.desy.mpi4j, mpi4j can be used in modular java9 application:
module com.foo.bar {
requires de.desy.mpi4j;
}MPI4J uses the linux kernel model where git is not only source repository, but also the way to track contributions and copyrights.
Each submitted patch must have a "Signed-off-by" line. Patches without this line will not be accepted.
The sign-off is a simple line at the end of the explanation for the patch, which certifies that you wrote it or otherwise have the right to pass it on as an open-source patch. The rules are pretty simple: if you can certify the below:
Developer's Certificate of Origin 1.1
By making a contribution to this project, I certify that:
(a) The contribution was created in whole or in part by me and I
have the right to submit it under the open source license
indicated in the file; or
(b) The contribution is based upon previous work that, to the best
of my knowledge, is covered under an appropriate open source
license and I have the right under that license to submit that
work with modifications, whether created in whole or in part
by me, under the same open source license (unless I am
permitted to submit under a different license), as indicated
in the file; or
(c) The contribution was provided directly to me by some other
person who certified (a), (b) or (c) and I have not modified
it.
(d) I understand and agree that this project and the contribution
are public and that a record of the contribution (including all
personal information I submit with it, including my sign-off) is
maintained indefinitely and may be redistributed consistent with
this project or the open source license(s) involved.
then you just add a line saying ( git commit -s )
Signed-off-by: Random J Developer <[email protected]>
using your real name (sorry, no pseudonyms or anonymous contributions.)
This work is published under MIT License