Applied Parallel Research's xHPF system

Abstract

Applied Parallel Research takes a somewhat different approach to High Performance Fortran than do other implementors. APR feels the real power of HPF is in its comment line directives by which the user can drive an automatic parallelization system. Rather than treating HPF as an altemative to automatic parallelization, we believe that it can be a powerful aid for automatic parallelization of existing Fortran 77 programs. W e have arrived at this point of view after a considerable effort to provide source-code global analyzers and parallelizers with extensive capabilities for large, real-world, sequential Fortran 77 programs. For example, our xHPF system will parallelize very complex Fortran 77 DO loops rather than relying on the user to explicitly expose parallel operations by translating to Fortran 90 array syntax. HPF’s data-distribution directives let us provide batch automatic parallelization tools, such as xHPF, in contrast to our interactive Forge 90 Distributed-Memory Parallelizer, which requires the user to explicitly direct the data decomposition of the arrays in the program. xHPF also accepts Fortran 90 array syntax and extends HPF data-distribution rules. APRs approach has been to provide HPF compilation systems that let users more easily port existing sequential Fortran 77 programs to MPP systems. APR feels that the market for tools that port existing Fortran programs to MPP systems far exceeds the market for tools to develop parallel programs from scratch.