28 lines
676 B
Elixir
28 lines
676 B
Elixir
defmodule Statistics do
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def basic(n) do
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{sum, sum2, hist} = generate(n)
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mean = sum / n
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stddev = :math.sqrt(sum2 / n - mean*mean)
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IO.puts "size: #{n}"
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IO.puts "mean: #{mean}"
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IO.puts "stddev: #{stddev}"
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Enum.each(0..9, fn i ->
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:io.fwrite "~.1f:~s~n", [0.1*i, String.duplicate("=", trunc(500 * hist[i] / n))]
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end)
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IO.puts ""
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end
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defp generate(n) do
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hist = for i <- 0..9, into: %{}, do: {i,0}
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Enum.reduce(1..n, {0, 0, hist}, fn _,{sum, sum2, h} ->
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r = :rand.uniform
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{sum+r, sum2+r*r, Map.update!(h, trunc(10*r), &(&1+1))}
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end)
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end
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end
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Enum.each([100,1000,10000], fn n ->
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Statistics.basic(n)
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end)
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