stddev pct contrib / rollapply / performanceanalytics / R / subscript out of bounds

Question

我正在尝试使用PerformanceAnalytics包为每个安全性构建滚动风险贡献。一旦我能够克服这个错误，我想绘制一段时间的结果。我一直收到下标超出范围的错误，我不知道从哪里开始解决它。具体是这个错误：

Error in `[.xts`(x, i, which.i = TRUE) : subscript out of bounds

对R不是很有经验感谢您的任何指导！这是代码。

library(PerformanceAnalytics)

symbols <- c("SPY","EEM","BND","BIL")

prices <- 
  getSymbols(symbols, src = 'yahoo', from = "2016-01-01", 
             auto.assign = TRUE, warnings = FALSE) %>% 
  map(~Cl(get(.))) %>% 
  reduce(merge) %>%
  `colnames<-`(symbols)

portfolioComponentReturns <- na.omit(Return.calculate(prices, method = "log"))

w = c(.25,.25,.25,.25)

rollingvolpct <- na.omit(rollapply(portfolioComponentReturns,

                                   width=252,
                                   FUN = function(Z)
                                   {
                                     t = StdDev(portfolioComponentReturns,weights = w, portfolio_method = "components", data = as.data.frame(Z), na.rm=T);
                                     return(t$pct_contrib)
                                   },
                                   by.column=FALSE, align="right"))