Discussion

We have described how a collective communication library for HPJava can be used for various parallel applications, and how the library itself can be implemented naturally in terms of the HPJava language primitives, plus some underlying, low-level set of messaging primitives. Some benchmark results are described here. We get reasonable performance for the simple problems like Laplace equation on the initial HPJava implementation. Results for the multigrid solver indicate further optimization for HPJava translation scheme and the Adlib is required. This work is in progress. A subset of the Adlib library has been available as a JNI wrapper to the C++ version for a couple of years. We have now finished the task of converting the whole library to Java. We have also implemented an inital ``reference'' and pure Java multi-threaded implementation of the low-level API mpjdev.