R “/.default”（残差，sigma）中出错：不一致数组

我试图运行一个garch模型，预测方差，然后使用自举法计算指数的价格。因此，我得到：

garchspec1 <- ugarchspec( mean.model = list(armaOrder = c(0,0)),
                     variance.model = list(model = "sGARCH"),
                     distribution.model = "norm")
garchfit1 <- ugarchfit(data = SP500returns , spec = garchspec)
garchforecast1 <- ugarchforecast(fitORspec = garchfit, n.ahead = 20)

sigmas = sigma(garchforecast1)
residuals  = residuals(garchfit1)


nus = residuals/sigmas

garchspec1