[R] Start Model for POLYCLASS

[Xiaogang Su]

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 at mail.ucf.edu
http://pegasus.cc.ucf.edu/~xsu/


>>> Spencer Graves <spencer.graves at 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 at mail.ucf.edu 
> http://pegasus.cc.ucf.edu/~xsu/ 
> 
> ______________________________________________
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> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html