Many metrics have been used to solve the problem of analyzing the history of software systems. Lehmann in 1, used a list of metrics and indicators in his project FEAST/1 to describe the size of aversion and specify evolutionary measurements which take into regard variance between sequential version.
Tudor G?rba et al. In 2, proposed matrix a cell in the matrix represents a class version and marked by a square, row in the matrix represents a class history and a column represents a system version.
Gold and Mohan in 3, presented a framework to characterize changes in source code in terms of notion descriptions provided by an automated program comprehension support tool. Also, they supported their framework with experiential proof derived from an analysis of various programs from a commercial system relating the changes observed to the types of maintenance being undertaken.
Michele Lanza proposed in 4, visualization technique called evolution matrix show the evolution of the classes of a software system .Every column of the matrix appears a version of the software, and each row appears the various versions of the same class. Two classes in two different versions are regarded the same if they have the same name.
Burd and Munro 5, by their studies investigating software evolution, defined an initial metric for estimate the software evolution process. It uses the calling structure of the code because it is an important component of the maintainer’s mental model.
Rysselberghe and Demeyer 6, applied simple technique based on information in version control systems to afford a summary of the evolution of systems. From all visualizations, only Ball converge the source code itself 7. He suggested several opinions which visualize different source code evolution measurements.
Holt 8, suggested a tool named Gase to visualize architectural changes between versions. Gall et al. 9, analyzed the history of changes in software systems to adjust the hidden dependencies between modules. Their analysis was at the file level, instead of dealing with the source code.
Filip and Serge 10, applied the technique to Tomcat, an open-source project by chose files as the first dimension in their visualization.The result will be 2-dimensional, where the horizontal axis appears the files in the system and the vertical axis the time of a change.