code: @Override
      public double hedge(double x) {
          return Op.isLE(x, 0.5)
                  ? Math.sqrt(x / 2.0)
                  : 1.0 - Math.sqrt((1.0 - x) / 2.0);
      }
docs: Computes the hedge for the membership function value `x`
  
  @param x is a membership function value
  @return ` \begin{cases} \sqrt{0.5x} & \mbox{if $x \le 0.5$} \cr
  1-\sqrt{0.5(1-x)} & \mbox{otherwise}\cr \end{cases}
  `