def test_simple_estimate_smaller(self):
hll = HyperLogLogPlusPlus(length=self.vector_length,
random_seed=42,
num_integer_bits=self.num_integer_bits)
one_vector = np.ones(self.vector_length)
hll.buckets = one_vector
alpha_16 = 0.673
hll_should_estimate = alpha_16 * self.vector_length**2 * 2 / self.vector_length
self.assertEqual(alpha_16, hll.alpha)
self.assertEqual(hll.estimate_cardinality(), hll_should_estimate)
def test_simple_estimate_larger(self):
m = 2**14
hll = HyperLogLogPlusPlus(length=m,
random_seed=42,
num_integer_bits=self.num_integer_bits)
thirty_vector = 30 * np.ones(m)
hll.buckets = thirty_vector
alpha_m = 0.7213 / (1 + 1.079 / m)
hll_should_estimate = alpha_m * m**2 * 2**30 / m
self.assertEqual(alpha_m, hll.alpha)
self.assertEqual(hll.estimate_cardinality(), hll_should_estimate)