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 <random@developer.example.org> using your real name (sorry, no pseudonyms or anonymous contributions.)
This work is published under MIT License