Co-change visualization applied to PostgreSQL and ArgoUML: (MSR challenge report)

Co-change visualization is a method to recover the subsystem structure of a software system from the version history, based on common changes and visual clustering. This paper presents the results of applying the tool CCVisu which implements co-change visualization, to the two open-source software systems PostgreSQL and ArgoUML The input of the method is the co-change graph, which can be easily extracted by CCVisu from a Cvs version repository. The output is a graph layout that places software artifacts that were often commonly changed at close positions, and artifacts that were rarely co-changed at distant positions. This property of the layout is due to the clustering property of the underlying energy model,which evaluates the quality of a produced layout. The layout can be displayed on the screen, or saved to a file in SVG or VRML format.