Class: LinearRegression

Inherits:

Object

• Object
• LinearRegression

show all

Defined in:

lib/plugins/open_flash_chart/lib/open_flash_chart/linear_regression.rb

Overview

Instance Attribute Summary (collapse)

• - (Object) offset

  Returns the value of attribute offset.

• - (Object) slope

  Returns the value of attribute slope.

Instance Method Summary (collapse)

• - (Object) fit
• - (LinearRegression) initialize(dx, dy = nil) constructor

  A new instance of LinearRegression.

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# File 'lib/plugins/open_flash_chart/lib/open_flash_chart/linear_regression.rb', line 7

def initialize dx, dy=nil
  @size = dx.size
  if @size == 1
    @slope, @offset = 1,0
    return
  end
  dy,dx = dx,axis() unless dy  # make 2D if given 1D
  raise "arguments not same length!" unless @size == dy.size
  sxx = sxy = sx = sy = 0
  dx.zip(dy).each do |x,y|
    sxy += x*y
    sxx += x*x
    sx  += x
    sy  += y
  end
  @slope = ( @size * sxy - sx*sy ) / ( @size * sxx - sx * sx )
  @offset = (sy - @slope*sx) / @size
end

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# File 'lib/plugins/open_flash_chart/lib/open_flash_chart/linear_regression.rb', line 5

def offset
  @offset
end

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# File 'lib/plugins/open_flash_chart/lib/open_flash_chart/linear_regression.rb', line 5

def slope
  @slope
end

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# File 'lib/plugins/open_flash_chart/lib/open_flash_chart/linear_regression.rb', line 26

def fit
  return axis.map{|data| predict(data) }
end