[R] logistic regression - using polys and products of features

From: Stephen Choularton <mail_at_bymouth.com>
Date: Fri 17 Jun 2005 - 07:39:30 EST


Hi  

I can get all my features by doing this:  

> logistic.model = glm(similarity ~ ., family=binomial, data =
cData[3001:3800,])    

I can get the product of all my features by this:  

logistic.model = glm(similarity ~ . ^ 2, family=binomial, data = cData[3001:3800,])  

I don't seem to be able to get polys by doing this:  

logistic.model = glm(similarity ~ poly(.,2), family=binomial, data = cData[3001:3800,])
Error in poly(., 2) : Object "." not found
>
 

How can I get polys?  

What do the warnings mean when I do this:  

> logistic.model = glm(similarity ~ . + . ^ 2, family=binomial, data =
cData[3001:3800,])
Warning messages:
1: Algorithm did not converge in: glm.fit(x = X, y = Y, weights = weights, start = start, etastart = etastart, 2: fitted probabilities numerically 0 or 1 occurred in: glm.fit(x = X, y = Y, weights = weights, start = start, etastart = etastart,
>
 

How can I do this?  

logistic.model = glm(similarity ~ . + . ^ 2 + poly(.,2), family=binomial, data = cData[3001:3800,])  

Thanks  

Stephen      

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Received on Fri Jun 17 07:43:40 2005

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