# File lib/matrix.rb, line 638
  def ** (other)
    if other.kind_of?(Integer)
      x = self
      if other <= 0
        x = self.inverse
        return Matrix.identity(self.column_size) if other == 0
        other = -other
      end
      z = x
      n = other  - 1
      while n != 0
        while (div, mod = n.divmod(2)
               mod == 0)
          x = x * x
          n = div
        end
        z *= x
        n -= 1
      end
      z
    elsif other.kind_of?(Float) || defined?(Rational) && other.kind_of?(Rational)
      Matrix.Raise ErrOperationNotDefined, "**"
    else
      Matrix.Raise ErrOperationNotDefined, "**"
    end
  end