class MoreMath::Histogram

A histogram gives an overview of a sequence’s elements.

def compute

Computes the histogram and returns it as an array of tuples (l, c, r). 
def compute
  @sequence.empty? and return []
  last_r = -Infinity
  min = @sequence.min
  max = @sequence.max
  step = (max - min) / bins.to_f
  Array.new(bins) do |i|
    l = min + i  * step
    r = min + (i + 1) * step
    c = 0
    @sequence.each do |x|
      x > last_r and (x <= r || i == bins - 1) and c += 1
    end
    last_r = r
    [ l, c, r ]
  end
end

def display(output = $stdout, width = 50)

+prepare_display+
Display this histogram to +output+, +width+ is the parameter for 
def display(output = $stdout, width = 50)
  d = prepare_display(width)
  for l, bar, r in d
    output << "%11.5f -|%s\n" % [ (l + r) / 2.0, "*" * bar ]
  end
  self
end

def initialize(sequence, bins = 10)

Create a Histogram for the elements of +sequence+ with +bins+ bins. 
def initialize(sequence, bins = 10)
  @sequence = sequence
  @bins = bins
  @result = compute
end

def prepare_display(width)

histogram bar.
edge. +width+ is usually an integer number representing the width of a
the +width+-normalized frequence count value, and +r+ the right bin
Returns an array of tuples (l, c, r) where +l+ is the left bin edge, +c+ 
def prepare_display(width)
  r = @result.reverse
  factor = width.to_f / (r.transpose[1].max)
  r.map { |l, c, r| [ l, (c * factor).round, r ] }
end

def to_a

Return the computed histogram as an array of arrays. 
def to_a
  @result
end