Class: Graphite::Tools::Regression

Inherits:
Object
  • Object
show all
Defined in:
lib/graphite/tools/regression.rb

Overview

Regression analysis of graphite data

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Regression

Returns a new instance of Regression.



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# File 'lib/graphite/tools/regression.rb', line 9

def initialize(data)
  @data = data
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/graphite/tools/regression.rb', line 7

def data
  @data
end

Instance Method Details

#datapoints ⇒ Object 



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# File 'lib/graphite/tools/regression.rb', line 13

def datapoints
  d = @data['datapoints'].map    { |(v, t)| [t, v] }
                         .reject { |_k, v| v.nil? }
  Hash[*d.flatten]
end

#forecast(*args) ⇒ Object 



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# File 'lib/graphite/tools/regression.rb', line 27

def forecast(*args)
  linefit.forecast(*args)
end

#linefit ⇒ Object 



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# File 'lib/graphite/tools/regression.rb', line 19

def linefit
  @linefit ||= begin
    f = LineFit.new
    f.setData(datapoints.keys, datapoints.values)
    f
  end
end

#x_intercept(y_val = 0) ⇒ Object 



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# File 'lib/graphite/tools/regression.rb', line 31

def x_intercept(y_val = 0)
  intercept, slope = linefit.coefficients
  Time.at((y_val - intercept) / slope) if slope && slope < 0
end