Unable to find forecast.Arima function in forecast package. Error displayed "forecast.Arima" not found. Can forecast function be used in place of 'forecast.Arima' function ? I am using forecast 8.1.
Secondly, the output from ARIMA is flat at mean for the future dates. Is this because I am using 'forecast' function.
library(forecast)
arima.forecast <- forecast(arima1, h=30)
forecast.Arima is not missing, it is just not exported in v8.1+. Use forecast instead, which will call forecast.Arima when required.
Flat forecasts are common. See https://robjhyndman.com/hyndsight/flat-forecasts/
来源：https://stackoverflow.com/questions/45193907/forecast-arima-function-missing-fromforecast-package