Hello,
Is this bias expected from the drawing method, say because it is
approximated and the approximation is weak at some points, or is there
an issue with its implementation, says some shift which gets smoothed
down for higher indexes?
I have checked paper where such implementation was proposed and there
theta allowed only on range between 0 and 1. It seems like it is not
guaranteed that it should work well when theta is more than 1.
Ok.
I see a significant issue with having a random_zipfian function which does
not really return a zipfian distribution under some parameter values. If
there is no better alternative, I would suggest to restrict the parameter
for values between 0 and 1, or to find a better approximation for theta >=
0.
I am attaching paper, see page 23.
Thanks for the paper. It reminds me that I intended to propose a
parametric pseudo-random permutation for pgbench, some day.
--
Fabien.
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