Class: Fit::ScientificDouble

Inherits:
Object
  • Object
show all
Defined in:
lib/fit/scientific_double.rb

Overview

Warning: not (yet) a general number usable in all calculations

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value) ⇒ ScientificDouble

Returns a new instance of ScientificDouble.



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# File 'lib/fit/scientific_double.rb', line 11

def initialize value
  @value = Float(value)
  @precision = 0
end

Instance Attribute Details

#precision ⇒ Object

Returns the value of attribute precision.



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# File 'lib/fit/scientific_double.rb', line 9

def precision
  @precision
end

Class Method Details

.precision(s) ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 26

def ScientificDouble.precision s
  value = s.to_f
  bound = tweak(s.strip).to_f
  (bound - value).abs
end

.tweak(s) ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 32

def ScientificDouble.tweak s
  pos = s.downcase.index('e')
  unless pos.nil?
    return tweak(s[0..(pos - 1)]) + s[pos..-1]
  end
  unless s.index('.').nil?
    return s + "5"
  end
  return s + ".5"
end

.value_of(s) ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 16

def ScientificDouble.value_of s
  if s.downcase.index('infinity')
    new (1.0/0.0) # Infinity
  else
    result = new s.to_f
    result.precision = precision s
    result
  end
end

Instance Method Details

#<=>(obj) ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 48

def <=> obj
  other = obj.to_f
  diff = @value - other

  # workaround the much more precise way of Ruby doing floats than Java
  return 0 if @precision.zero? and diff.abs < 1.0e-5

  precision = @precision > obj.precision ? @precision : obj.precision      
  return -1 if diff < -precision
  return 1 if diff > precision
  return 0 if @value.nan? and other.nan?
  return 1 if @value.nan?
  return -1 if other.nan?
  0
end

#==(obj) ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 43

def == obj
  sd = ScientificDouble.value_of obj.to_s
  self.<=>(sd) == 0
end

#nan? ⇒ Boolean

unused?

Returns:

  • (Boolean) 


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# File 'lib/fit/scientific_double.rb', line 64

def nan?; @value.nan?; end

#to_f ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 65

def to_f; @value; end

#to_s ⇒ Object 



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# File 'lib/fit/scientific_double.rb', line 66

def to_s; @value.to_s; end