[R] S.O.S "try" doesnot work in boot?
ctu at bigred.unl.edu
ctu at bigred.unl.edu
Tue Sep 9 09:22:33 CEST 2008
First thanks for Jinsong's suggestions
I would like to do a bootstrap in a nonlinear model. But it fails to
converge in most of time. (it did converge if I just use nls without
boot). Thus, I use "try" function to resolve my problem. This
following code is from Jinsong's suggestion.
h1a.nls<-nls(density~nmf(time, alpha, delta, psi, tau, gamma),data=h1a,
start=c(alpha=0.3, delta=0.08869, psi=1.26523, tau=3.93919,
gamma=-1.41927))
h1a.data<-data.frame(h1a,res=resid(h1a.nls),fitted=fitted(h1a.nls))
h1a.fun<-function(data,i){
d<-data
d$density<-d$fitted+d$res[i]
try(update(h1a.nls,data=d),silent=T)
if(!inherits(h1a.nls,"try-error")) h1a.coef<-coef(h1a.nls)
else h1a.coef<-NA
h1a.coef
}
h1a.boot<-boot(h1a.data, statistic = h1a.fun, R=1000)
> h1a.boot
ORDINARY NONPARAMETRIC BOOTSTRAP
Call:
boot(data = h1a.data, statistic = h1a.fun, R = 1000)
Bootstrap Statistics :
original bias std. error
t1* 0.27892590 0 0
t2* 0.08869433 0 0
t3* 1.26523275 0 0
t4* 3.93919567 0 0
t5* -1.41926966 0 0
all of the values of each column in h1a.boot$t are the same.
Is anyone know to how I can solve this problem?
Appreciate in advance
Chunhao
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