====== Class: SocialNetwork ======

====== Description ======
Class SocialNetwork calculates basic features of social network. For example, each college is a component. We calculate the component basic features such as density, diameter, average path length, number of nodes, average degree, average degree centrality, average people PageRank, average closeness and average betweenness. 

====== Parameter ======
  - Graph G
====== Return ======
  - Matrix SN with row denotes different college, columns denote basic feature value.
====== Detail Information ======
  - related python modules: networkx, MySQLdb
  - networkx:[[https://pypi.python.org/pypi/networkx/]]
  - MySQLdb:[[https://pypi.python.org/pypi/MySQL-python]]

====== Functions ======
  - SocialNetwork(G):construction function.
  - ShowInformation(): Return basic features of graph.
  - GetDensity(): Return density of graph.
  - GetAPL(): Return average shortest path length of graph.
  - GetPeopleRank(): Calculate average page rank of people as graph's rank.Return page rank value of graph.
  - GetBetweenness(): Return average betweenness of each nodes in graph.
  - GetCloseness(): Return average closeness of each nodes in graph.
  - GetDegree(): Return degree distribution of graph.
  - GetDegreeCentrality(): Return degree centrality of graph.