[R] function return

[David Winsemius]

On Jul 22, 2010, at 5:27 PM, Daniel Hocking wrote:

> I am sorry if this question is vague or uninformed.  I am just
> learning R and struggling.  I am using the book Hierarchical Modeling
> and Inference in Ecology and they provide examples of R code.  I have
> the following code from the book but when I run it I don't get any
> output.  I cannot get the values of 'out' to show up.  Basically, I
> just want to see my estimates for b0, b1, b2, and b3.  Any time that I
> have used or see function( ) there have been arguments and I just call
> for the value of the function.  In this case there doesn't seem to be
> a value for the function.  Any help would be appreciated.

You have defined a function that has no arguments. You should be  
typing  this at the console:

panel3pt1.fn()

I get an error because there is no such file on my machine and you  
have not provided a link to an accessible copy.

-- 
David.


>
> Thanks,
> Dan
>
>
> `panel3pt1.fn` <-
> function(){
>
> source("utilfns.Rd")
>
> data<- read.table("wtmatrix.txt",header=T,na.strings=T)
> elev<-data[,"elev"]
> forest<-data[,"forest"]
> elev<-scale(elev,center=TRUE)
> forest<-scale(forest,center=TRUE)
> pamat<-data[,c("y.1","y.2","y.3")]
> z<-pamat[,1]
> M<-length(z)
>
>
> lik<-function(parms){
>     b0<-parms[1]
>     b1<-parms[2]
>     b2<-parms[3]
>     b3<-parms[4]
>     ones<-rep(1,M)
>     ### Compute binomial success probabilities
>     probs<-expit(b0*ones+b1*elev+b2*(elev^2)+b3*forest)
>     lik<-rep(0,length(z))
>     ### evaluate log of binomial pmf
>     tmp<-log(dbinom(z,1,probs))
>     ### substitute 0 for missing values
>     lik[!is.na(z)]  <-  tmp[!is.na(z)]
>     lik<-  -1*sum(lik)
>     return(lik)
> }
>
>  out <- nlm(lik,c(0,0,0,0),hessian=TRUE)
>
>  return(out)
>
>
> }
>
> ------------------------------------------------------------------------------------
> Daniel J. Hocking
> 122 James  Hall
> Department of Natural Resources & the Environment
> University of New Hampshire
> Durham, NH 03824
>
> dhocking at unh.edu
> http://sites.google.com/site/danieljhocking/
> www.hockingphotography.smugmug.com
>
> "Without data, all you are is just another person with an opinion."
> -------------------------------------------------------------------------------------
>
>
>
>
>
>
>
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>
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David Winsemius, MD
West Hartford, CT