Use np.int8 for HLL array because its values will never exceed 64

Author: svpcom

hyperloglog/hll.py

@@ -97,7 +97,7 @@ def __init__(self, error_rate):
         self.alpha = get_alpha(p)
         self.p = p
         self.m = 1 << p
-        self.M = np.zeros(self.m, int)
+        self.M = np.zeros(self.m, np.int8)
 
     def __getstate__(self):
         return dict([x, getattr(self, x)] for x in self.__slots__)