28 lines
637 B
Ruby
28 lines
637 B
Ruby
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# hll-err.rb - Copyright (C) 2014 Salvatore Sanfilippo
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# BSD license, See the COPYING file for more information.
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#
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# Check error of HyperLogLog Redis implementation for different set sizes.
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require 'rubygems'
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require 'redis'
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require 'digest/sha1'
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r = Redis.new
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r.del('hll')
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i = 0
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while true do
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100.times {
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elements = []
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1000.times {
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ele = Digest::SHA1.hexdigest(i.to_s)
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elements << ele
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i += 1
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}
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r.pfadd('hll',elements)
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}
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approx = r.pfcount('hll')
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abs_err = (approx-i).abs
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rel_err = 100.to_f*abs_err/i
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puts "#{i} vs #{approx}: #{rel_err}%"
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end
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