[R] extend.series not zero padding
spencer.graves at pdf.com
Sat Dec 10 03:12:38 CET 2005
The documentation for "extend.series" indicates that "zero" is an
option for "method". However, consider the followining:
> extend.series(c(0, pi), method="zero")
Error in extend.series(c(0, pi), method = "zero") :
Invalid argument value for 'method'
If you replace "zero" with "zeros" in the documentation, it will be
consistent with the actual function behavior:
> extend.series(c(0, pi), method="zeros")
 0.000000 3.141593 0.000000 0.000000
Permit me to outline for your general edification how I found this.
First, I installed "wavelets" and replicated your error. I noticed
that your sample series was named "c". Since that's also a function
name, I replaced "c" with "c.". That did not fix the error. However, I
generally avoid using the names of standard functions for other
purposes. In most but not all cases, R can tell from the context
whether the function or the non-function object 'c' should be used. To
avoid being trapped by this in the occasionally cases where R can NOT
tell the difference, I routine type a variabile name at a command prompt
before using it: If I get 'object not found', I feel more comfortable
using it. If R returns something, I tend to avoid that name.
Next, I tried to simplify your example. I determined from the
documnetation that we should be able to delete the last two arguments
and still get the same thing. I therefore tried the following:
When I got the same error message, I then listed the function by
typing "extend.series" at a command prompt and copied the text into a
script file so I could look at it.
Then I invoked "debug(extend.series)" and tried the
'dew0<-extend.series(...)" command again. From this, I found it failed
on the following:
if (is.na(match(method, c("periodic", "reflection", "zeros",
I then tried it with "method='zeros'", and it worked.
Then, in preparing an email to Eric Aldrich, I simplified the example
still further to make it easier for him to understand the issue.
hope this helps.
Keith Chamberlain wrote:
> Dear List,
> I was trying to verify that I could use extend.series in the wavelets
> package and kept getting an error when trying to use method="zero". I'm not
> seeing where my syntax has gone awry.
> According to the documentation, [see ?extend.series]
> " method: A character string indicating which extension method to use.
> Possible values are '"periodic"', '"reflection"', '"zero"',
> '"mean"', and '"reflection.inverse"'."
> c<-cbind(0:60, 60:0) # setup a series, length will be 61
>  122
>>Error in extend.series(c, method = "zero", length = "powerof2", j =
> log(length(c), :
> Invalid argument value for 'method'
> Other methods work great, such as method="mean".
>  128
> Has this come up in anyone else's experience? If so, what's the workaround
> so that I can use "zero" as a method?
> R-help at stat.math.ethz.ch mailing list
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Spencer Graves, PhD
Senior Development Engineer
PDF Solutions, Inc.
333 West San Carlos Street Suite 700
San Jose, CA 95110, USA
spencer.graves at pdf.com
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