valkey/utils/hyperloglog/hll-err.rb

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# hll-err.rb - Copyright (C) 2014 Salvatore Sanfilippo
# BSD license, See the COPYING file for more information.
#
# Check error of HyperLogLog Redis implementation for different set sizes.
require 'rubygems'
require 'redis'
require 'digest/sha1'
r = Redis.new
r.del('hll')
(1..1000000000).each{|i|
ele = Digest::SHA1.hexdigest(i.to_s)
r.hlladd('hll',ele)
if i != 0 && (i%10000) == 0
approx = r.hllcount('hll')
abs_err = (approx-i).abs
rel_err = 100.to_f*abs_err/i
puts "#{i} vs #{approx}: #{rel_err}%"
end
}