Fortran: a modern standard programming language for parallel scalable high performance technical computing

Abstract

Fortran is often thought of as an old, archaic programming language that used to be adequate for technical computing but is rapidly being replaced by more modern languages such as C and, especially, C++. No perception could be less accurate. Fortran has been modernized by the standardization process that lead to Fortran 90, and further enhanced with features developed by the High Performance Fortran Forum, many of which have been incorporated in the Fortran 95 draft standard. This modernization makes Fortran the ideal programming language for the development of new technical computing applications or the modernization of legacy codes written in FORTRAN 77. Indeed, since Fortran 90 provides all of the features of FORTRAN 77, initial conversion of a legacy application typically only requires recompilation. This paper provides a quick overview of "modern" Fortran for the development of numerically intensive technical computing applications and looks at some simple examples. These examples are chosen to be illustrative of a data parallel coding style that is readable and understandable, performs well on a single processor system, and scales well on multiple processor shared memory and distributed memory systems. Compilers supporting this style of programming are available from a number of vendors.