Program Composition Notation
(PCN) A specification language for parallelism between C and Fortran modules. PCN provides a simple language for specifying concurrent algorithms, interfaces to Fortran and C, a portable toolkit that allows applications to be developed on a workstation or small parallel computer and run unchanged on supercomputers and integrated debugging and performance analysis tools. PCN was developed at Argonne National Laboratory and the California Institute of Technology. It has been used to develop a wide variety of applications, in areas such as climate modelling, fluid dynamics, computational biology, chemistry, and circuit simulation.