Class: LargeBinomials::LargeFloat

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/large_binomials/large_float.rb

Overview

Class modeling floats larger than Ruby’s regular float. They consist of a regular float (the mantissa) plus an additional exponent of 10.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(m, e = 0) ⇒ LargeFloat

Returns a new instance of LargeFloat.



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# File 'lib/large_binomials/large_float.rb', line 29

def initialize(m, e = 0)
  @mantissa = m.to_f
  @exponent = e
end

Instance Attribute Details

#exponent ⇒ Object

Returns the value of attribute exponent.



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# File 'lib/large_binomials/large_float.rb', line 27

def exponent
  @exponent
end

#mantissa ⇒ Object

Returns the value of attribute mantissa.



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# File 'lib/large_binomials/large_float.rb', line 27

def mantissa
  @mantissa
end

Instance Method Details

#*(other) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 46

def *(other)
  if other.instance_of? LargeFloat
    multiply_with_large_float(other)
  else
    multiply_with_numeric(other)
  end
end

#+(other) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 97

def +(other)
  if self < other
    other + self
  else
    LargeFloat.new(new_mantissa_for_addition(other), @exponent)
  end
end

#/(other) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 73

def /(other)
  if other.instance_of? LargeFloat
    divide_by_large_float(other)
  else
    divide_by_numeric(other)
  end
end

#<=>(other) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 117

def <=>(other)
  normalize
  other.normalize
  if @exponent == other.exponent
    @mantissa - other.mantissa
  else
    @exponent - other.exponent
  end
end

#clone ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 34

def clone
  LargeFloat.new(@mantissa, @exponent)
end

#divide_by_large_float(lf) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 81

def divide_by_large_float(lf)
  quotient = self / lf.mantissa
  quotient.exponent -= lf.exponent
  quotient
end

#divide_by_numeric(n) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 87

def divide_by_numeric(n)
  quotient = clone
  quotient.mantissa /= n
  quotient
end

#multiply_with_large_float(lf) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 54

def multiply_with_large_float(lf)
  product = self * lf.mantissa
  product.exponent += lf.exponent
  product
end

#multiply_with_numeric(i) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 60

def multiply_with_numeric(i)
  product = clone
  new_mantissa = product.mantissa * i
  product.normalize if new_mantissa == Float::INFINITY
  new_mantissa = product.mantissa * i
  if new_mantissa == Float::INFINITY
    product.exponent += 1
    i /= 10
  end
  product.mantissa *= i
  product
end

#new_mantissa_for_addition(lf) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 93

def new_mantissa_for_addition(lf)
  @mantissa + lf.mantissa * 10**(lf.exponent - @exponent)
end

#normalize ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 38

def normalize
  unless @mantissa == 0
    normalization = Math.log10(@mantissa.abs).floor
    @mantissa /= 10**normalization
    @exponent += normalization
  end
end

#superscript(i) ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 105

def superscript(i)
  s = i.to_s
  s = s.gsub(/1/, '¹').gsub(/2/, '²').gsub(/3/, '³').gsub(/4/, '⁴')
  s = s.gsub(/5/, '⁵').gsub(/6/, '⁶').gsub(/7/, '⁷').gsub(/8/, '⁸')
  s.gsub(/9/, '⁹').gsub(/0/, '⁰').gsub(/-/, '⁻')
end

#to_s ⇒ Object 



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# File 'lib/large_binomials/large_float.rb', line 112

def to_s
  normalize
  "#{@mantissa}×10#{superscript(@exponent)}"
end