Class: Malge::ErrorFittedFunction::AExpBX32

Inherits:
Malge::ErrorFittedFunction show all
Defined in:
lib/malge/errorfittedfunction/aexpbx32.rb

Overview

Assumed y = a * exp(a * (x **3/2))

NOTE: @coefficients might become negative value. Need discussion for dealing?

Instance Attribute Summary

Attributes inherited from Malge::ErrorFittedFunction

#coefficients, #diff_abs_pairs, #raw_pairs

Instance Method Summary collapse

Methods inherited from Malge::ErrorFittedFunction

#count_equal_under_over, #initialize, #summary, #variance

Constructor Details

This class inherits a constructor from Malge::ErrorFittedFunction

Instance Method Details

#equation ⇒ Object 



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# File 'lib/malge/errorfittedfunction/aexpbx32.rb', line 21

def equation
  sprintf("%f \* exp(%f \* x**(3.0/2.0))", * @coefficients)
end

#expected_error(x) ⇒ Object 



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# File 'lib/malge/errorfittedfunction/aexpbx32.rb', line 25

def expected_error(x)
  @coefficients[0] * Math::exp( @coefficients[1] * x **(3.0/2.0))
end

#fit ⇒ Object 



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# File 'lib/malge/errorfittedfunction/aexpbx32.rb', line 10

def fit
  inv_pairs =  @diff_abs_pairs.map {|pair|
    x = pair[0] ** (3.0/2.0)
    y = Math::log(pair[1])
    [x,y]
  }
  inv_pairs.delete_if {|pair| ! pair[1].finite?} 
  @coefficients = Malge::LeastSquare.least_square_1st_degree(inv_pairs)
  @coefficients[0] = Math::exp @coefficients[0]
end

#most_strict_pair ⇒ Object 



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# File 'lib/malge/errorfittedfunction/aexpbx32.rb', line 39

def most_strict_pair
  @raw_pairs.max_by{ |pair| pair[0] }
end

#x(y) ⇒ Object

y = a * exp(a x*(3/2)) a * exp(a x*(3/2)) = y exp(a x*(3/2)) = y/a a x*(3/2) = log( y/a) x**(3/2) = log( y/a)/a x = (log( y/a)/a)**(2/3)



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# File 'lib/malge/errorfittedfunction/aexpbx32.rb', line 35

def x(y)
  return (Math::log( y / @coefficients[0])/@coefficients[1]) **(2.0/3.0)
end