代码具体实现了simerank的算法实现，适用于小规模的图中计算，大规模的则需要使用分布式算法，第一个算法是基础实现，第二个是使用了平方缓存，加速了算法的收敛速度。(The code realizes the implementation of the algorithm of simerank, which is suitable for computing in small scale. The large scale needs to use distributed algorithm.