Class: Rational

Inherits:
Numeric show all
Defined in:
opal/opal/corelib/rational.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Numeric

#%, #+@, #-@, #[], #__coerced__, #abs2, #angle, #clone, #conj, #div, #divmod, #dup, #fdiv, #i, #imag, #integer?, #negative?, #nonzero?, #polar, #positive?, #real, #real?, #rect, #to_c, #to_int, #zero?

Methods included from Comparable

#<, #<=, #>, #>=, #between?, normalize

Constructor Details

#initialize(num, den) ⇒ Rational

Returns a new instance of Rational

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# File 'opal/opal/corelib/rational.rb', line 50

def initialize(num, den)
  @num = num
  @den = den
end

Instance Attribute Details

#denominator ⇒ Object (readonly)

Returns the value of attribute denominator


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# File 'opal/opal/corelib/rational.rb', line 48

def denominator
  @denominator
end

#numerator ⇒ Object (readonly)

Returns the value of attribute numerator


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# File 'opal/opal/corelib/rational.rb', line 48

def numerator
  @numerator
end

Class Method Details

.convert(num, den) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 22

def self.convert(num, den)
  if num.nil? || den.nil?
    raise TypeError, "cannot convert nil into Rational"
  end

  if Integer === num && Integer === den
    return reduce(num, den)
  end

  if Float === num || String === num || Complex === num
    num = num.to_r
  end

  if Float === den || String === den || Complex === den
    den = den.to_r
  end

  if den.equal?(1) && !(Integer === num)
    Opal.coerce_to!(num, Rational, :to_r)
  elsif Numeric === num && Numeric === den
    num / den
  else
    reduce(num, den)
  end
end

.reduce(num, den) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 4

def self.reduce(num, den)
  num = num.to_i
  den = den.to_i

  if den == 0
    raise ZeroDivisionError, "divided by 0"
  elsif den < 0
    num = -num
    den = -den
  elsif den == 1
    return new(num, den)
  end

  gcd = num.gcd(den)

  new(num / gcd, den / gcd)
end

Instance Method Details

#*(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 146

def *(other)
  case other
  when Rational
    num = @num * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num * other, @den)

  when Float
    to_f * other

  else
    __coerced__ :*, other
  end
end

#**(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 188

def **(other)
  case other
  when Integer
    if self == 0 && other < 0
      return Float::INFINITY
    elsif other > 0
      Rational(@num ** other, @den ** other)
    elsif other < 0
      Rational(@den ** -other, @num ** -other)
    else
      Rational(1, 1)
    end

  when Float
    to_f ** other

  when Rational
    if other == 0
      Rational(1, 1)
    elsif other.denominator == 1
      if other < 0
        Rational(@den ** other.numerator.abs, @num ** other.numerator.abs)
      else
        Rational(@num ** other.numerator, @den ** other.numerator)
      end
    elsif self == 0 && other < 0
      raise ZeroDivisionError, "divided by 0"
    else
      to_f ** other
    end

  else
    __coerced__ :**, other
  end
end

#+(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 108

def +(other)
  case other
  when Rational
    num = @num * other.denominator + @den * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num + other * @den, @den)

  when Float
    to_f + other

  else
    __coerced__ :+, other
  end
end

#-(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 127

def -(other)
  case other
  when Rational
    num = @num * other.denominator - @den * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num - other * @den, @den)

  when Float
    to_f - other

  else
    __coerced__ :-, other
  end
end

#/(other) ⇒ Object Also known as: divide, quo

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# File 'opal/opal/corelib/rational.rb', line 165

def /(other)
  case other
  when Rational
    num = @num * other.denominator
    den = @den * other.numerator

    Rational(num, den)

  when Integer
    if other == 0
      to_f / 0.0
    else
      Rational(@num, @den * other)
    end

  when Float
    to_f / other

  else
    __coerced__ :/, other
  end
end

#<=>(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 92

def <=>(other)
  case other
  when Rational
    @num * other.denominator - @den * other.numerator <=> 0

  when Integer
    @num - @den * other <=> 0

  when Float
    to_f <=> other

  else
    __coerced__ :<=>, other
  end
end

#==(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 76

def ==(other)
  case other
  when Rational
    @num == other.numerator && @den == other.denominator

  when Integer
    @num == other && @den == 1

  when Float
    to_f == other

  else
    other == self
  end
end

#abs ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 224

def abs
  Rational(@num.abs, @den.abs)
end

#ceil(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 228

def ceil(precision = 0)
  if precision == 0
    (-(-@num / @den)).ceil
  else
    with_precision(:ceil, precision)
  end
end

#coerce(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 63

def coerce(other)
  case other
  when Rational
    [other, self]

  when Integer
    [other.to_r, self]

  when Float
    [other, to_f]
  end
end

#floor(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 238

def floor(precision = 0)
  if precision == 0
    (-(-@num / @den)).floor
  else
    with_precision(:floor, precision)
  end
end

#hash ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 246

def hash
  "Rational:#@num:#@den"
end

#inspect ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 250

def inspect
  "(#{to_s})"
end

#rationalize(eps = undefined) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 256

def rationalize(eps = undefined)
  %x{
    if (arguments.length > 1) {
      #{raise ArgumentError, "wrong number of arguments (#{`arguments.length`} for 0..1)"};
    }

    if (eps == null) {
      return self;
    }

    var e = #{eps.abs},
        a = #{self - `e`},
        b = #{self + `e`};

    var p0 = 0,
        p1 = 1,
        q0 = 1,
        q1 = 0,
        p2, q2;

    var c, k, t;

    while (true) {
      c = #{`a`.ceil};

      if (#{`c` <= `b`}) {
        break;
      }

      k  = c - 1;
      p2 = k * p1 + p0;
      q2 = k * q1 + q0;
      t  = #{1 / (`b` - `k`)};
      b  = #{1 / (`a` - `k`)};
      a  = t;

      p0 = p1;
      q0 = q1;
      p1 = p2;
      q1 = q2;
    }

    return #{Rational(`c * p1 + p0`, `c * q1 + q0`)};
  }
end

#round(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 302

def round(precision = 0)
  return with_precision(:round, precision) unless precision == 0
  return 0 if @num == 0
  return @num if @den == 1

  num = @num.abs * 2 + @den
  den = @den * 2

  approx = (num / den).truncate

  if @num < 0
    -approx
  else
    approx
  end
end

#to_f ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 319

def to_f
  @num / @den
end

#to_i ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 323

def to_i
  truncate
end

#to_r ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 327

def to_r
  self
end

#to_s ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 331

def to_s
  "#@num/#@den"
end

#truncate(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 335

def truncate(precision = 0)
  if precision == 0
    @num < 0 ? ceil : floor
  else
    with_precision(:truncate, precision)
  end
end

#with_precision(method, precision) ⇒ Object

Raises:

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# File 'opal/opal/corelib/rational.rb', line 343

def with_precision(method, precision)
  raise TypeError, "not an Integer" unless Integer === precision

  p = 10 ** precision
  s = self * p

  if precision < 1
    (s.send(method) / p).to_i
  else
    Rational(s.send(method), p)
  end
end