High Performance Applications: State-of-the-Art and Future Requirements*

In the past, most high performance applications dealt with numerical simulation, and parallel machines were essentially used only by a relatively small group of dedicated professionals which had to cope with the idiosyncrasies of the machine at a low level of abstraction. This situation is changing quickly, driven by enhanced hardware and software support offered by a new generation of parallel computers, and the rapid expansion of global networks that lead to the feasibility of applications distributed over geographically widely distant areas. In this paper, we discuss the language support required for the efficient handling of advanced applications. We will outline the major features of Vienna Fortran and compare the language to High Performance Fortran (HPF), a de-facto standard in this area. A significant weakness of HPF is its lack of support for many advanced applications, which require irregular data distributions and dynamic load balancing. We introduce HPF+, an extension of HPF based on Vienna Fortran, that provides the required functionality.