[Rd] Re: predict.Arima fails when x is not a time-series
Prof Brian D Ripley
Thu, 4 Apr 2002 06:35:03 +0100 (BST)
On Wed, 3 Apr 2002, David Brahm wrote:
> I'm playing with predict.Arima in the 3/19/02 development snapshot of R-devel.
That's quite old.
> The following produces an error message because x is not of class "ts":
> R> x <- rnorm(20)
> R> obj <- arima(x, c(2,0,0))
> R> predict(obj)
> Error in round(x, digits) : Non-numeric argument to mathematical function
> Granted the documentation for arima says x should be a time-series, but why not
> accommodate simple vectors?
Because it is not possible to specify the time base correctly when
> I think it would suffice to change this line:
> xtsp <- tsp(data)
> in predict.Arima to this:
> xtsp <- tsp(hasTsp(data))
> Also, a minor documentation typo: the help file for predict.Arima refers to the
> function as "predict.arima" at one point.
Not any more it doesn't.
> -- David Brahm (email@example.com)
Brian D. Ripley, firstname.lastname@example.org
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
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