Class: Bmg::Summarizer::Percentile

Inherits:
Bmg::Summarizer show all
Defined in:
lib/bmg/summarizer/percentile.rb

Overview

Percentile summarizer.

Example:

# direct ruby usage
Bmg::Summarizer.percentile(:qty, 50).summarize(...)

Instance Attribute Summary

Attributes inherited from Bmg::Summarizer

#functor, #options

Instance Method Summary collapse

Methods inherited from Bmg::Summarizer

avg, by_proc, collect, concat, count, distinct, #happens, max, min, multiple, percentile, stddev, sum, summarization, #summarize, #to_summarizer_name, variance

Constructor Details

#initialize(attribute = nil, nth = 50, &bl) ⇒ Percentile

Returns a new instance of Percentile.



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# File 'lib/bmg/summarizer/percentile.rb', line 13

def initialize(attribute = nil, nth = 50, &bl)
  attribute, nth = nil, attribute if attribute.is_a?(Integer)
  super(*[attribute].compact, &bl)
  @nth = nth
end

Instance Method Details

#_happens(memo, val) ⇒ Object

Collects the value



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# File 'lib/bmg/summarizer/percentile.rb', line 25

def _happens(memo, val)
  memo << val
end

#finalize(memo) ⇒ Object

Finalizes the computation.



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# File 'lib/bmg/summarizer/percentile.rb', line 30

def finalize(memo)
  return nil if memo.empty?
  index = memo.size * (@nth / 100.0)
  above = [[index.ceil - 1, memo.size - 1].min, 0].max
  below = [index.floor - 1, 0].max
  sorted = memo.sort
  (sorted[above] + sorted[below]) / 2
end

#least ⇒ Object

Returns [] as least value.



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# File 'lib/bmg/summarizer/percentile.rb', line 20

def least()
  []
end