
Hello all. 

I have been working on a (fairly simple) function for way too long. I’ve really hit a wall and I was hoping someone might be able to point me in the right direction. 

 

I have (attempted) to create a function that has an embedded while loop. The while loop works fine by itself, however, when the while loop is embedded in the function, the function fails. I’m not sure why this happens as the function really doesn’t add much above and beyond the while loop. I believe it might have something to do with the list I define in the while loop as ‘nlme.control.parms.’ Because I included print(nlme.control.parms) when the while loop runs by itself the paramers of nlme.control.parms can be seen to be fine. However, when I run the function print(nlme.control.parms) is full of NAs. I’m not sure if the function fails because the list nlme.control.parms is full of NAs or if nlme.control.parms is full of NAs because the function failed. 

 

I should mention that the function is (supposed to be!) used with nlme so that multiple sets of parameters can be defined (each next set being less restrictive than the previous), and nlme runs until it outputs results given the particular set of parameters. The values I used in the simplified example that follows would never be used in a real situation, but for purposes of this illustrative example, the parameters are fine. The result should be a list of the nlme object and 'OK' (which should be 5 for the example). I'm using R version 1.9.1 on Windows XP.

 

Thanks for any thoughts, Ken

 

################

library(nlme)

data(Loblolly)

 

maxIter <- c(1, 1, 1, 1, 1)

returnObject <- c(FALSE, FALSE, FALSE, FALSE, TRUE)

 

nlsList.Object <- nlsList(SSasymp, Loblolly)

 

M1 <- function(maxIter, returnObject)

{

 

ok <- FALSE

OK <- 0

 

while(ok==FALSE)

{

OK <- OK + 1  

 

nlme.control.parms <- list("maxIter"=maxIter[OK], "returnObject"=returnObject[OK])

 

fm1 <- try(nlme(nlsList.Object,

    fixed = Asym + R0 + lrc ~ 1,

    random = Asym ~ 1,

    control = nlme.control.parms), silent=TRUE)

              

ok <- is.numeric(fm1$numIter)

print(OK)

print(nlme.control.parms)

}

return(list(fm1, OK))

}

 

Test <- M1(maxIter=maxIter, returnObject=returnObject)


		
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