Disassortativity and degree distribution of software coupling networks in object-oriented software systems

In this paper, empirical investigation results on degree distribution and disassortativity of four open software systems have been presented with the view of reasonable description of software structure. We make use of a directed software coupling network to characterize and describe the macroscopic properties of four open software systems. Implement reviewing of the degree distribution of four open source software and find that the in-degree distribution is of scale-free property but the out-degree distribution can be well described by stretched exponential distribution. And then we examine disassortativity of the software coupling network, and draw a conclusion that software coupling network is disassortative mixing in undirected versions, and negative correlation between two classes of directed SCNs has existed.