NL: A parallel programming visual language

The dataflow programming model provides a simple way of expressing an algorithm which exploits all the parallelism available in a program. The challenge is to provide a sufficiently powerful programming system which exploits the low level parallelism while allowing the programmer to work at a high level of abstraction. This paper describes NL. a visual dataflow language designed for parallel applications. NL retains the dataflow firing rule, which is the key to low level parallelism, but adds a set of high level constructs which enable a programmer to work at appropriate levels of abstraction. Some of the key advantages of NL are: maximum parallelism is exposed by providing eager arrays (structures which can be processed before their computation is complete) and allowing inter-iteration parallelism: programmers do not need to explicitly add synchronisation points as they are a natural by product of the dataflow model and a parallel program can be debugged in the same form in which it was originally written.