[R] Two repeated warnings when runing gam(mgcv) to analyze my dataset?

From: zhijie zhang <epistat_at_gmail.com>
Date: Fri, 14 Dec 2007 01:46:03 +0800


Dear all,
 I run the GAMs (generalized additive models) in gam(mgcv) using the following codes.

m.gam
<-gam(mark~s(x)+s(y)+s(lstday2004)+s(ndvi2004)+s(slope)+s(elevation)+disbinary,family=binomial(logit),data=point)

 And two repeated warnings appeared.
Warnings:
1: In gam.fit(G, family = G$family, control = control, gamma = gamma, ... :   Algorithm did not converge

2: In gam.fit(G, family = G$family, control = control, gamma = gamma, ... :   fitted probabilities numerically 0 or 1 occurred

Q1: For warning1, could it be solved by changing the value of mgcv.toloptions for
gam.control(mgcv.tol=1e-7)?

Q1: For warning2, is there any impact for the results if the "fitted probabilities numerically 0 or 1 occurred" ? How can i solve it?

 I didn't try the possible solutions for them, because it took such a longer time to run the whole programs.
 Could anybody suggest their solutions?
 Any help or suggestions are greatly appreciated.   Thanks.

-- 
With Kind Regards,

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::\_)::(..):: :::::::)./::: ::::::(_/:::: ::::::::::::: [***********************************************************************] Zhi Jie,Zhang ,PHD Tel:+86-21-54237149 Dept. of Epidemiology,School of Public Health,Fudan University Address:No. 138 Yi Xue Yuan Road,Shanghai,China Postcode:200032 Email:epistat_at_gmail.com Website: www.statABC.com [***********************************************************************] oooO::::::::: (..):::::::::
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Received on Thu 13 Dec 2007 - 17:49:47 GMT

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