docs: public static double quantile(double x, double location, double shape) {
      return (x == .5) ? location : (x <= .5) //
          ? x <= 0. ? x < 0. ? Double.NaN : Double.NEGATIVE_INFINITY //
              : location - shape / FastMath.tan(Math.PI * x) //
          : x >= 1. ? x > 1. ? Double.NaN : Double.POSITIVE_INFINITY //
              : location + shape / FastMath.tan(Math.PI * (1 - x));
    }