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coxme: model simplification using LR-test?

3 messages · Terry Therneau, Simon Tragust, David Winsemius

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Summary of the query: "update" does not work on a coxme object

 I ran into this bug myself 2 days ago -- I rarely use update() so
hadn't encountered it before.  The problem is that coxme breaks the
formula into fixed and random portions, and this confuses the default
method for formula.

Solution: add the following function:
  formula.coxme <- function(x, ...) x$call$formula

 This method will be included in my next update of coxme.

Terry Therneau
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Many thanks for the suggestion.

I tried it already, but as I've never wrote a function, I had no luck. 
If it's not asked too much, maybe you or somebody else could help me 
getting the code for the function right.

Regards
Simon


Am 20/02/2012 14:52, schrieb Terry Therneau:

  
    
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On Feb 20, 2012, at 11:41 AM, Simon Tragust wrote:

            
"it" means .. what exactly?
"no luck" means ... what?
He gave you a perfectly formed function. Were you thinking you had to  
fill in some blanks? Not so. That "..." is a meaningful construct in  
R. It says to take whatever arguments follow and pass them on to the  
next function.  So when you enter this at the console:

  m<-coxme(Surv(day,status) ~ condition*infection +
                             (1|infection/population), data=all)
  formula.coxme<- function(x, ...) x$call$formula
  m1<-update(m, ~.-condition:infection)

.... what happens?