2015-11-18 06:14:39 +00:00
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defmodule RC do
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def entropy(str) do
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leng = String.length(str)
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2016-12-05 22:15:40 +01:00
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String.graphemes(str)
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2015-11-18 06:14:39 +00:00
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|> Enum.group_by(&(&1))
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|> Enum.map(fn{_,value} -> length(value) end)
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|> Enum.reduce(0, fn count, entropy ->
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freq = count / leng
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entropy - freq * :math.log2(freq)
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end)
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end
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end
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IO.inspect RC.entropy("1223334444")
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