```
# NOT RUN {
library(xts)
data(sample_matrix)
sample.xts <- as.xts(sample_matrix)
calcReturns <- function(price, method = c("discrete", "log")){
px <- try.xts(price)
method <- match.arg(method)[1L]
returns <- switch(method,
simple = ,
discrete = px / lag(px) - 1,
compound = ,
log = diff(log(px)))
reclass(returns, px)
}
# plot the Close
plot(sample.xts[,"Close"])
# calculate returns
addPanel(calcReturns, method="discrete", type="h")
# Add simple moving average to panel 1
addPanel(rollmean, k=20, on=1)
addPanel(rollmean, k=40, col="blue", on=1)
# }
```

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