Measuring the Entropy of Large Software Systems

Snider, Greg

HP Development Company

关键词: entropy;    software systems;    structure;    metric;   

RP-ID  :  HPL-2001-221

学科分类：计算机科学（综合）

美国|英语

来源: HP Labs

【 摘 要 】

How does one measure a large software system to determine if it is "well-structured"? This report proposes a metric for doing just that, based on the concept of entropy from information theory. A tool that automatically extracts the metric from source code was built and used to compare two large software systems (each about 500,00 lines of source code): a commercial application that has existed and been heavily modified for several decades; and a recent rewrite of the same system that aimed at producing a well-structured system. The rewritten system was shown to have much lower entropy in each of its subsystems, compared to the legacy system, as well as much lower entropy overall. 12 Pages