//根据BAW模型计算美式期权隐含波动率
return Black_Scholes_America_IV(1,0,4986,5300,1.5,0.07,0.028373,1.5);
//结果为12.7518803996707
//为了避免没有收敛到最优解,此时可以考虑更改初值再迭代一次
return Black_Scholes_America_IV(1,0,4986,5300,1.5,0.07,0.028373,1.5,12.75);
//结果为12.7083837771018
//或者可以考虑增加迭代的次数,此时也可达到最优解
return Black_Scholes_America_IV(1,0,4986,5300,1.5,0.07,0.028373,1.5,50,1E-6,2000);
//结果为12.7083838542107
//可以考虑参考欧式期权BS模型的隐含波动率结果来设置初值
sigma_s:=OptionImpliedVolatilitylu(1,0,4986,5300,1.5,0.07,0.028373,1.5,0,500);
return Black_Scholes_America_IV(1,0,4986,5300,1.5,0.07,0.028373,1.5,sigma_s,1E-6,2000);