[R] Help fix last line of my optimization code

Uwe Ligges ligges at statistik.tu-dortmund.de
Fri Jul 1 14:13:02 CEST 2011


Please

a) read the posting guide
b) really submit reproducible code. Yours is not.
c) read ?optimize and learn to specify the interval
d) you specified an argument init.params, but that is not used in 
optimize() nor can it be usefully passed to llik.

Uwe Ligges



On 01.07.2011 02:46, Edward Bowora wrote:
> Hi
>
> I need help figure out how to fix my code.
>
> When I call into R
>> optimize(llik,init.params=F)
>   I get this error message
> ####Error in optimize(llik, init.params = F) : element 1 is empty;
>     the part of the args list of 'min' being evaluated was:
>     (interval)####
>
>
> My data and my code looks like below.
>
>
> R_j		R_m
> 0.002		0.026567296
> 0.01		0.003194435
> .		.
> .		.
> .		.
> .		.
> 0.0006	0.010281122
>
> a=read.table("D:/ff.txt",header=T)
> attach(a)
> llik=function(R_j,R_m)
> #The parameters al_j, au_j, b_j ,
> and sigma_j need to be estimated and there are no initial estimates to
> them.
> if(R_j<  0)
> {
>   LF=sum[log(1/(2*pi*(sigma_j^2)))-(1/(2*(sigma_j^2))*(R_j+al_j-b_j*R_m))^2]
> }else if(R_j>0)
> {
>   LF=sum[log(1/(2*pi*(sigma_j^2)))-(1/(2*(sigma_j^2))*(R_j+au_j-b_j*R_m))^2]
> }else
> {
>   LF=sum[(log(pnorm((au_j-b_j*R_m)/sigma_j)-pnorm((al_j-b_j*R_m)/sigma_j)))]
> }
> optimize(llik,init.params=F)
> Error in optimize(llik, init.params = F) : element 1 is empty;
>     the part of the args list of 'min' being evaluated was:
>     (interval)
>
> Thank you
>
> Edward
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



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