Re: [R] Start Model for POLYCLASS

From: Xiaogang Su <xiaosu_at_mail.ucf.edu>
Date: Tue 11 Jul 2006 - 05:41:30 EST


Dear Dr. Graves,

Thanks for your information and kindness! I really appreciate it. According to my findings so far, POLYCLASS doesnot seem to allow for variables being forced into the model. Even the commercialized MARS doesnot have this function either. However, one ad hoc approach that they suggested is to fit linear (or logistic) model and form rediduals first and then run MARS with the residuals.

Best regards,
-XG Su



Xiaogang Su, Assistant Professor
Department of Statistics and Actuarial Science University of Central Florida
Orlando, FL 32816
(407) 823-2940 [O]
xiaosu@mail.ucf.edu
http://pegasus.cc.ucf.edu/~xsu/

>>> Spencer Graves <spencer.graves@pdf.com> 7/7/2006 5:49:05 AM >>>

          I have not seen a reply, so I will offer a few suggestions, even
though I've never used the 'polspline' package. I scanned several of the help pages and looked in "~\library\polspline' where R is installed

on my hard drive and found no further documentation, and I found nothing
new from RSiteSearch("polyclass"). Googling for 'polyclass' led me to

"http://bear.fhcrc.org/~clk/soft.html", the home page for Charles Kooperberg, the author and maintainer. If it were my problem, I might

try writing him directly at the email address given in help(package="polyclass"); I'm including him as a "cc" on this reply.

          I spent time looking at this, because 'polyclass', 'polymars' and
'polspline' seem potentially related related to one of my secondary interests. Unfortunately, I couldn't find sufficient documentation to

allow me to proceed with the time I felt I could afford to invest in this right now.

          If it were my problem, before I wrote another email about this, I'd
first list the function 'polyclass', make a local copy, then work through an example line by line using 'debug(polyclass)'. This 'debug'

facility is remarkably powerful and easy to use. I've solved many problems like this using 'debug' in this way.

          If that failed to provide the necessary enlightenment, I'd submit
another post including a self-contained example based on a modification

of the 'iris' example featured in the 'polyclass' help page. Your example is NOT self contained, so I would NOT use that. Using the 'iris' example would make it much easier to explain clearly what you want. It also makes it much easier for someone like me to experiment with alternatives and describe what I did in terms of a tested example.

          Hope this helps.
p.s. I suggest you also review the posting guide! "www.R-project.org/posting-guide.html".

Xiaogang Su wrote:
> Dear all,
>
> I have a question on how to set up the starting model in POLYCLASS
and
> make sure the terms in the starting model retained in the final
> POLYCLASS model.
>
> In the function POLYMARS, this can be done using the STARTMODEL
option.
> See below for example, I started with model
> y= b0 + b1*X1 + b2*X2 + b3*X4 + b4*X5 + b5*X2*X5 + e
>

>> m00 <- matrix(c(

> 1, NA, 0, NA, 1,
> 2, NA, 0, NA, 1,
> 4, NA, 0, NA, 1,
> 5, NA, 0, NA, 1,
> 2, NA, 5, NA, 1),nrow = 5, ncol=5, byrow=TRUE);
>
>> m2 <- polymars(response=PID2$y, predictors=PID2[,1:7], 

> startmodel=m00)
>> summary(m2)  

>
> But I could not figure out how this works for POLYCLASS. There is an
> option FIT in POLYCLASS, which needs to be a POLYCLASS object though.

>
> Any suggestion or information is greatly appreciated.
>
> Sincerely,
> Xiaogang Su
>
>
> ================================
> Xiaogang Su, Assistant Professor
> Department of Statistics and Actuarial Science
> University of Central Florida
> Orlando, FL 32816
> (407) 823-2940 [O]
> xiaosu@mail.ucf.edu
> http://pegasus.cc.ucf.edu/~xsu/
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jul 11 05:47:05 2006

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