[Rd] kernapply.ts
Prof Brian Ripley
ripley at stats.ox.ac.uk
Wed Nov 2 17:20:48 CET 2011
On Wed, 2 Nov 2011, Pierre Chausse wrote:
> I have a suggestion for kernapply for ts objects. When we choose the
> option circular=F, the returned series don't have the correct dates. The
That's a matter of opinion. A kernel is applied in the same way as an
MA filter, to historical data.
> removed dates are all at the beginning instead of half at the beginning
> and half at the end. It is particularly useful when we need to smooth
> the series (or remove a trend using a filter) before estimating a model
> (like in macroeconomics) or simply to plot the original series with the
> smoothed one. Of course, there is always the option of doing it by hand
> of the use circular=T and trim the series but I thought it would be
> nicer that way.
>
> Here is my suggestion (maybe not the nicest way to do it but it works)
>
>
> kernapply.ts <- function (x, k, circular = FALSE, ...)
> {
> if (!is.matrix(x))
> {
> y <- kernapply.vector(as.vector(x), k, circular=circular)
> ts (y, end=end(x), frequency=frequency(x))
> }
> else
> y <- apply(x, MARGIN=2L, FUN=kernapply, k, circular=circular)
>
> if(circular)
> ts (y, end=end(x), frequency=frequency(x))
> else
> {
> y <- as.ts(y)
> t1 <- tsp(x)[1]+(length(k[[1]])-1)/tsp(x)[3]
> t2 <- tsp(x)[2]-(length(k[[1]])-1)/tsp(x)[3]
> tsp(y) <- c(t1,t2,tsp(x)[3])
> return(y)
> }
> }
>
> --
> *Pierre Chauss?*
> Assistant Professor
> Department of Economics
> University of Waterloo
>
> [[alternative HTML version deleted]]
>
>
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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