Solving the Linda multiple rd problem

Abstract

Linda is a co-ordination language that has been used for many years. From our recent work on the model we have found a simple operation that is widely used in many different algorithms which the Linda model is unable to express in a viable fashion. We examine a function which performs the composition of two binary relations. By examining how to implement this in parallel using Linda we demonstrate that the current methods are unacceptable. A more detailed explanation of the problem, which we call the multiple rd problem is then presented, together with some other algorithms which have the same problem. We then show how the addition of a primitive to the Linda model, copy-collect, extends the expressibility of the model to overcome this problem. This work builds on previous work on the addition of another primitive called collect[1]. The parallel composition of two binary relations is then reconsidered using copy-collect and is shown to be more efficient.