Ruby BigDecimal Method Error : Using Ruby v2.2.1  with following code, i am getting  Error 

- r56.rb:6:in `<module:BigMath>': undefined method `log_slow' for module `BigMath' (NameError)
	from r56.rb:5:in `<main>'

i have created log_slow alias and it is not working



    require 'bigdecimal'  
    require 'bigdecimal/math'  
    require 'bigdecimal/util'

    module BigMath
	    alias :log :log_slow
	    def log(x, prec)
		if x <= 0 || prec <= 0
			raise ArgumentError, "Zero or negative argument for log"
		end
		return x if x.infinite? || x.nan?
		sign, fraction, power, exponent = x.split
		fraction = BigDecimal(".#{fraction}")
		power = power.to_s.to_d
		log_slow(fraction, prec) + (log_slow(power, prec) * exponent)
	end
    end

    include BigMath
    number = BigDecimal("1234.5678")
    Math.log(number)
    prec = 50
    puts BigMath.log_slow(number, prec).round(prec).to_s("F")
    puts BigMath.log(number, prec).round(prec).to_s("F")
    puts BigMath.log(number ** 1000, prec).round(prec).to_s("F")


  
