Verify distribution uniformity/Naive: Difference between revisions
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(Update Factor implementation: some functions were simplified thanks to John Benediktsson.) |
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{{task|Probability and statistics}} |
{{task|Probability and statistics}} |
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<small>This task is an adjunct to [[Seven-dice from |
<small>This task is an adjunct to [[Seven-sided dice from five-sided dice]].</small> |
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Create a function to check that the random integers returned from a small-integer generator function have uniform distribution. |
Create a function to check that the random integers returned from a small-integer generator function have uniform distribution. |
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* An 'error' if the distribution is not flat enough. |
* An 'error' if the distribution is not flat enough. |
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Show the distribution checker working when the produced distribution is flat enough and when it is not. (Use a generator from [[Seven-dice from |
Show the distribution checker working when the produced distribution is flat enough and when it is not. (Use a generator from [[Seven-sided dice from five-sided dice]]). |
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See also: |
See also: |
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4 200016 |
4 200016 |
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5 200424</pre> |
5 200424</pre> |
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=={{header|Elixir}}== |
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{{trans|Erlang}} |
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<lang elixir>defmodule VerifyDistribution do |
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def naive( generator, times, delta_percent \\ 3 ) do |
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dict = Enum.reduce( List.duplicate(generator, times), Map.new, fn f,d -> update_counter(f,d) end ) |
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values = for x <- Dict.keys(dict), do: Dict.get(dict, x) |
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average = Enum.sum( values ) / Dict.size( dict ) |
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delta = average * (delta_percent / 100) |
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fun = fn {_key, value} -> abs(value - average) > delta end |
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too_large_dict = Enum.filter( dict, fun ) |
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return( Dict.size(too_large_dict), too_large_dict, average, delta_percent ) |
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end |
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def return( 0, _too_large_dict, _average, _delta ), do: :ok |
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def return( _n, too_large_dict, average, delta ) do |
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{:error, {Dict.to_list(too_large_dict), :failed_expected_average, average, 'with_delta_%', delta}} |
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end |
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def update_counter( fun, dict ), do: Dict.update( dict, fun.(), 1, fn(val) -> val+1 end ) |
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end |
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:random.seed(:erlang.now) |
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fun = fn -> Dice.dice7 end |
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IO.inspect VerifyDistribution.naive( fun, 100000, 3 ) |
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IO.inspect VerifyDistribution.naive( fun, 100, 3 )</lang> |
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{{out}} |
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<pre> |
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:ok |
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{:error, |
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{[{1, 16}, {2, 10}, {4, 15}, {5, 8}, {6, 20}, {7, 17}], |
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:failed_expected_average, 14.285714285714286, 'with_delta_%', 3}} |
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</pre> |
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=={{header|Erlang}}== |
=={{header|Erlang}}== |
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