public static /*@Real*/ double blackFormulaImpliedStdDevApproximation(
            final PlainVanillaPayoff payoff,
            @Real final double strike,
            @Real final double forward,
            @Real final double blackPrice,
            @DiscountFactor final double discount) {
        // TODO : complete
        return blackFormulaImpliedStdDevApproximation(payoff, strike, forward, blackPrice, discount, 0.0);
    }
public static double blackFormulaImpliedStdDevApproximation(
            final PlainVanillaPayoff payoff,
            @Real final double strike,
            @Real final double forward,
            @Real final double blackPrice,
            @DiscountFactor final double discount) {
       
        return blackFormulaImpliedStdDevApproximation(payoff, strike, forward, blackPrice, discount, 0.0);
    }
public static double blackformulaimpliedstddevapproximation( final plainvanillapayoff payoff, @real final double strike, @real final double forward, @real final double blackprice, @discountfactor final double discount) { return blackformulaimpliedstddevapproximation(payoff, strike, forward, blackprice, discount, 0.0); }