Невычисляются греки опционов

var bs = new BlackScholes(_options, trader, trader) {
RiskFree =0,
Dividend =0,
RoundDecimals =2
};

DateTimeOffset currentTime = DateTimeOffset.Now;

var delta = bs.Delta(currentTime);
var gamma = bs.Gamma(currentTime);
var vega = bs.Vega(currentTime);
var theta = bs.Theta(currentTime);
var rho = bs.Rho(currentTime);