method

sqrt

v2_1_10 - Show latest stable - 0 notes - Class: Math

1_8_6_287 (0)
1_8_7_72 (0)
1_8_7_330 (0)
1_9_1_378 (-7)
1_9_2_180 (0)
1_9_3_125 (38)
1_9_3_392 (0)
2_1_10 (0)
2_2_9 (0)
2_4_6 (0)
2_5_5
2_6_3
What's this?

sqrt(a) private

Computes the square root of a. It makes use of Complex and Rational to have no rounding errors if possible.

Math.sqrt(4/9)      # => 2/3
Math.sqrt(- 4/9)    # => Complex(0, 2/3)
Math.sqrt(4.0/9.0)  # => 0.666666666666667

Show source

# File lib/mathn.rb, line 226
  def sqrt(a)
    if a.kind_of?(Complex)
      abs = sqrt(a.real*a.real + a.imag*a.imag)
#      if not abs.kind_of?(Rational)
#        return a**Rational(1,2)
#      end
      x = sqrt((a.real + abs)/Rational(2))
      y = sqrt((-a.real + abs)/Rational(2))
#      if !(x.kind_of?(Rational) and y.kind_of?(Rational))
#        return a**Rational(1,2)
#      end
      if a.imag >= 0
        Complex(x, y)
      else
        Complex(x, -y)
      end
    elsif a.respond_to?(:nan?) and a.nan?
      a
    elsif a >= 0
      rsqrt(a)
    else
      Complex(0,rsqrt(-a))
    end
  end

sqrt

Related methods