I have wrote a function that forecasts a time series object using different forecast methods like forecast::nnetar, forecast::tbats, forecast::Arima and forecast::ets.
I know that forecastHybrid::hybridModel function is doing this, I just wanted to create something more customized. So I am now returning a list with result$mean, result$error and result$fit. I want to use accuracy or plot function like forecast object. Is there a easy way to do that? or is it too complicated?
EDIT: About the function, it takes a ts object, an arima model-that I found by taking differences and checking ACF-PACF graphs- and a horizon to be forecasted. It applies nnetar, ets, tbats and my arima model.
It combines their fits and forecasts and create a new fit values and forecast values.
It returns a list object with forecasted values as result$mean (this is also same in forecast objects), fitted values as result$fit and errors as result$error.
Now with that returned object, I cant automate some series of works like having accuracy, making plots etc. So I want to return a forecast object if it is possible. that is what it is.
A forecast object is just a list containing a few items, and given a class "forecast". Look at any of the existing functions to see how to do it. Here is a very simple template:
myfun <- function(x, h, ...)
{
# Compute some forecasts
fc <- ....
# Construct output list
output <- list(mean=fc, x=x, ...)
# Return with forecasting class
return(structure(output, class='forecast'))
}