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From: "Jerry " <mricad@yahoo.no000spppam.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: coxphfit in Statistics toolbox
Date: Mon, 5 May 2008 19:00:20 +0000 (UTC)
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"Tom Lane" <tlane@mathworks.com> wrote in message 
<fvfjlp$9jp$1@fred.mathworks.com>...
> > Since the source code is not accessible for this 
function,
> > can you provide more specific reference on the 
algorithm
> > used? I know two books are listed in the Matlab 
documents,
> > is there a particular chapter describing an algorithm 
that
> > Matlab implemented exactly?
> 
> Jerry, as Steve pointed out you can type "edit coxphfit" 
to see the code.
> 
> The books "Analysis of Survival Data" by Cox and Oakes 
(chapter 7), and 
> "Statistical Models and Methods for Lifetime Data" by 
Lawless (also chapter 
> 7), are two good references for this material.  The code 
might not exactly 
> follow either one step-by-step, but either should be 
helpful.
> 
> -- Tom 
> 

Thanks very much, Tom. I didn't say it clearly last time --
 there is an optimization function (statsfminbx) being 
called in coxphfit which sometimes generates some warning 
messages that I don't know how to deal with. Is this 
function described somewhere? Also, when there is 
censoring in the response data, does coxphfit require that 
the number of events (ie, exact observations) to be larger 
than the number of covariates?

Thanks again for your help.