[R] package "wavelets" does nor recognize filter "d2"

mauede at alice.it
Fri, 20 Feb 2009 16:23:52 -0000

I take the liberty of pasting the on-line documentation for package
"wavelets", functions "dwt" and  "wt.filter",
pertinent to the wavelet/filter choice.
While I apologize for my verbose messages with huge attachments, I encourage
whoever loads packages to CRAN to take some minutes to reread the attached
documentation.

Usage
dwt(X, filter="la8", n.levels, boundary="periodic",
fast=TRUE)

filter Either a wt.filter object, a character string indicating which wavelet
filter to use in the decomposition, or a numeric vector of wavelet coefficients
(not scaling coefficients). See help(wt.filter) for acceptable filter names

wt.filter(filter="la8", modwt=FALSE)

Arguments
filter A character string indicating which wavelet transform filter to compute
....

Details
The character strings currently supported are derived from one of four classes
of wavelet transform filters: Daubechies, Least Asymetric, Best Localized and
Coiflet. The prefixes for filters of these classes are d, la, bl and c,
respectively. Following the prefix, the filter name consists of an integer
indicating length. Supported lengths are as follows:

Daubechies
2,4,6,8,10,12,14,16,18,20.
Least Asymetric
8,10,12,14,16,18,20.

Now let's try to pick filter "d2" ....

> X1 <- c(.2,-.4,-.6,-.5,-.8,-.4,-.9,0,-.2,.1,-.1,.1,.7,.9,0,.3)
> X2 <- c(.2,-.4,-.6,-.5,-.8,-.4,-.9,0,-.2,.1,-.1,.1,-.7,.9,0,.3)
>
> # combine them and compute DWT
> newX <- cbind(X1,X2)
> wt <- dwt(newX,filter="d2", n.levels=3,
boundary="reflection", fast=FALSE)
Error in wt.filter(filter) : Invalid filter name.

> wt.filter("d2")
Error in wt.filter("d2") : Invalid filter name.

Regards,
Maura





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