def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def init(num_players):
	global MAP_WIDTH,MAP_HEIGHT,N_ITERATIONS,H_RATIO,W_RATIO,MIN_ROOM_SIDE,CENTER_HUB_HOLE,CENTER_HUB_RADIO,MAP_NAME
	MAP_WIDTH=int(500*sqrt(num_players))
	MAP_HEIGHT=MAP_WIDTH
	N_ITERATIONS=log(MAP_WIDTH*100,2)
	H_RATIO=0.49
	W_RATIO=H_RATIO
	MIN_ROOM_SIDE = 32
	CENTER_HUB_HOLE = 32
	CENTER_HUB_RADIO = CENTER_HUB_HOLE-MIN_ROOM_SIDE/2
	MAP_NAME="result%s.png"%MAP_WIDTH