A Modern Fortran Interface in OpenSHMEM Need for Interoperability with Parallel Fortran Using Coarrays

Abstract

Languages and libraries based on Partitioned Global Address Space (PGAS) programming models are convenient for exploiting scalable parallelism on large applications across different domains with irregular memory access patterns. OpenSHMEM is a PGAS-based library interface specification. As a result of using legacy non-standard Fortran features, support for Fortran language bindings is deprecated in OpenSHMEM specification version 1.4. In this work, we propose a new OpenSHMEM interface using the Fortran-C interoperability bind(C) feature introduced in Fortran 2003 language standard. This new interface is implemented over the existing C-language bindings in the OpenSHMEM specification. Through this work, we intend to showcase the expressiveness of the new proposed interface, along with its productivity and performance benefits that can be extracted in applications with irregular memory access patterns.