Class: Flt::Num

Inherits:
Object
  • Object
show all
Includes:
Nio::Formattable
Defined in:
lib/nio/rtnlzr.rb,
lib/nio/rtnlzr.rb,
lib/nio/fmt.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Nio::Formattable

append_features, #nio_round, #nio_write

Class Method Details

.nio_read_neutral(neutral) ⇒ Object 



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# File 'lib/nio/fmt.rb', line 1730

def self.nio_read_neutral(neutral)
  x = nil
  
  if neutral.special?
    case neutral.special
    when :nan
      x = num_class.nan
    when :inf
      x = num_class.infinity(neutral.sign=='-' ? '-1.0' : '+1.0')
    end
  elsif neutral.rep_pos<neutral.digits.length
    
    # uses num_clas.context.precision TODO: ?
    x = num_class.new Rational(*neutral.to_RepDec.getQ)
    
  else
    if neutral.base==num_class.radix
      if neutral.base==10
        str = neutral.sign
        str += neutral.digits
        str += "E#{(neutral.dec_pos-neutral.digits.length)}"
        x = num_class.new(str)
      else
        f = neutral.digits.to_i(neutral.base)
        e = neutral.dec_pos-neutral.digits.length
        s = neutral.sign=='-' ? -1 : +1
        x = num_class.Num(s, f, e)
      end
    else
      # uses num_clas.context.precision TODO: ?
      if num_class.respond_to?(:power)
        x = num_class.Num(neutral.digits.to_i(neutral.base).to_s)
        x *= num_class.Num(neutral.base.to_s)**(neutral.dec_pos-neutral.digits.length)
        x = -x if neutral.sign=='-'
      else
        
        # uses num_clas.context.precision TODO: ?
        x = num_class.new Rational(*neutral.to_RepDec.getQ)
        
      end
    end
  end
  
  return x
end

Instance Method Details

#nio_r(tol = nil) ⇒ Object 



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# File 'lib/nio/rtnlzr.rb', line 132

def nio_r(tol = nil)
  tol ||= Flt.Tolerance(Rational(1,2),:ulps)
  case tol
    when Integer
      Rational(*Nio::Rtnlzr.max_denominator(self,tol,num_class))
    else
      Rational(*Nio::Rtnlzr.new(tol).rationalize(self))
  end
end

#nio_write_neutral(fmt) ⇒ Object 



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# File 'lib/nio/fmt.rb', line 1775

def nio_write_neutral(fmt)
  neutral = Nio::NeutralNum.new
  x = self
  
  if x.nan?
    neutral.set_special(:nan)
  elsif x.infinite?
    neutral.set_special(:inf, x<0 ? '-' : '+')
  else
    converted = false
    if fmt.get_ndig==:exact && fmt.get_approx==:simplify
      
      neutral = x.nio_r(Flt.Tolerance('0.5', :ulps)).nio_write_neutral(fmt)
      # TODO: find better method to accept the conversion
      prc = (fmt.get_base==num_class.radix) ? x.number_of_digits : x.coefficient.to_s(fmt.get_base).length
      prc = [prc, 8].max
      converted = true if neutral.digits.length<prc
      
    elsif fmt.get_approx==:exact && fmt.get_base!=num_class.radix
      # TODO: num_class.context(:precision=>fmt....
      neutral = x.to_r.nio_write_neutral(fmt)
      converted = true
    end
    if !converted
      if fmt.get_base==num_class.radix
        sign = x.sign==-1 ? '-' : '+'
        txt = x.coefficient.to_s(fmt.get_base)  # TODO: can use x.digits directly?
        dec_pos = rep_pos = x.fractional_exponent
        neutral.set sign, txt, dec_pos, nil, fmt.get_base_digits, false ,fmt.get_round
        converted = true
      end
    end
    if !converted
      
      min_exp  =  num_class.context.etiny
      n = x.number_of_digits
      s,f,e = x.split
      b = num_class.radix
      if s < 0
        sign = '-'
      else
        sign = '+'
      end
      prc = x.number_of_digits
      f = num_class.int_mult_radix_power(f, prc-n)
      e -= (prc-n)

      inexact = true

      rounding = case fmt.get_round
      when :even
        :half_even
      when :zero
        :half_down
      when :inf
        :half_up
      when :truncate
        :down
      when :directed_up
        :up
      when :floor
        :floor
      when :ceil
        :ceil
      else
        nil
      end
      

      # TODO: use Num#format instead
      # Note: it is assumed that fmt will be used for for input too, otherwise
      # rounding should be Float.context.rounding (input rounding for Float) rather than fmt.get_round (output)
      formatter = Flt::Support::Formatter.new(num_class.radix, num_class.context.etiny, fmt.get_base)
      formatter.format(x, f, e, rounding, prc, fmt.get_all_digits?)
      inexact = formatter.round_up if formatter.round_up.is_a?(Symbol)
      dec_pos,digits = formatter.digits
      txt = ''
      digits.each{|d| txt << fmt.get_base_digits.digit_char(d)}
      neutral.set sign, txt, dec_pos, nil, fmt.get_base_digits, inexact, fmt.get_round
      
    end
  end
  
  return neutral
end

#nio_xr ⇒ Object 



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# File 'lib/nio/rtnlzr.rb', line 80

def nio_xr
  to_r
end