def __init__(self, error_rate, window, lpfm=None):
"""
Implementes a Sliding HyperLogLog
error_rate = abs_err / cardinality
"""
self.window = window
if lpfm is not None:
m = len(lpfm)
p = int(round(math.log(m, 2)))
if (1 << p) != m:
raise ValueError('List length is not power of 2')
self.LPFM = lpfm
else:
if not (0 < error_rate < 1):
raise ValueError("Error_Rate must be between 0 and 1.")
# error_rate = 1.04 / sqrt(m)
# m = 2 ** p
p = int(math.ceil(math.log((1.04 / error_rate)**2, 2)))
m = 1 << p
self.LPFM = [None for i in range(m)]
self.alpha = get_alpha(p)
self.p = p
self.m = m
def __init__(self, error_rate, window, lpfm=None):
"""
Implementes a Sliding HyperLogLog
error_rate = abs_err / cardinality
"""
self.window = window
if lpfm is not None:
m = len(lpfm)
p = int(round(math.log(m, 2)))
if (1 << p) != m:
raise ValueError("List length is not power of 2")
self.LPFM = lpfm
else:
if not (0 < error_rate < 1):
raise ValueError("Error_Rate must be between 0 and 1.")
# error_rate = 1.04 / sqrt(m)
# m = 2 ** p
p = int(math.ceil(math.log((1.04 / error_rate) ** 2, 2)))
m = 1 << p
self.LPFM = [None for i in range(m)]
self.alpha = get_alpha(p)
self.p = p
self.m = m
def test_alpha(self):
alpha = [get_alpha(b) for b in range(4, 10)]
self.assertEqual(alpha, [0.673, 0.697, 0.709, 0.7152704932638152, 0.7182725932495458, 0.7197831133217303])
def test_alpha(self):
alpha = [get_alpha(b) for b in range(4, 10)]
self.assertEqual(alpha, [
0.673, 0.697, 0.709, 0.7152704932638152, 0.7182725932495458,
0.7197831133217303
])