[R] Splines under tension
dwinsemius at comcast.net
Wed May 12 20:41:55 CEST 2010
On May 12, 2010, at 2:37 PM, Greg Snow wrote:
> I think this last line is a fortune candidate:
> It's not just that different disciplines rediscover the same ideas,
> they also relabel them.
With apologies to Aretha: I second that emotion.
> Gregory (Greg) L. Snow Ph.D.
> Statistical Data Center
> Intermountain Healthcare
> greg.snow at imail.org
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Terry Therneau
>> Sent: Wednesday, May 12, 2010 6:49 AM
>> To: sam.e
>> Cc: r-help at r-project.org
>> Subject: Re: [R] Splines under tension
>> ---begin included message ---
>> Does anyone know if R has a function for splines under tension. I
>> there are numerous packages for spline interpolation within R i just
>> can't find one that lets you determine the tension factor.
>> In the statistics literature these are called "smoothing splines".
>> instance the s(x) construct in gam or pspline(x) in a coxph formula.
>> There are multiple ways to specify the 'tension factor', many in the
>> statistics community prefer the 'equivalent degrees of freedom' so
>> will often see df=___ in the examples. You can also directly enter a
>> penalty mulitplier.
>> To get a clearer answer you would need to give the explicit
>> definition of "tension factor" from the literature you are quoting.
>> It's not just that different disciplines rediscover the same ideas,
>> also relabel them.
>> Terry Therneau
>> R-help at r-project.org mailing list
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> and provide commented, minimal, self-contained, reproducible code.
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
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