english_punctuations = [',', '.', ':', ';', '?', '(', ')', '[', ']', '&', '!', '*', '@', '#', '$', '%']
re_han_default = re.compile("([\u4E00-\u9FD5a-zA-Z0-9+#&._]+)", re.U)
re_skip_default = re.compile("(\r\n|\s)", re.U)
泊松分布
def poisson(L):
"""
poisson distribution
return a integer random number, L is the mean value
"""
p = 1.0
k = 0
e = math.exp(-L)
while p >= e:
u = random.random() #generate a random floating point number in the range [0.0, 1.0)
p *= u
k += 1
return k-1
负指数分布
def expntl(L):
"""
negative exponential distribution
return a double random number, L is the mean value
"""
u = random.random()
return -L * math.log(u)