Dear BUGS users,
I am new to WinBUGS and am wondering if anyone can
help me. I am trying to add random spatial effects to a logistic model of
daily nest survival for wetland birds. Currently I am trying to use
spatial.exp to introduce the random effects, but keep getting error messages
that say "undefined real result". I've adjusted the priors and initial
values numerous times, but nothing seems to work. I should say that I am
analyzing 11 discrete wetland patches, and am only interested in within
patch spatial autocorrelation. I have tried analyzing one patch at a
time and that doesn't seem to work either. Does anyone have any
advice on what to do?
Here's the model I am trying to run:
model{
tau ~ dgamma(0.1,0.1)
phi
~ dunif(0,100)
b0 ~ dnorm(0.0,0.1)
b1 ~
dnorm(0.0,0.1)
b2 ~ dnorm(0.0,0.1)
for (i in 1:n){
noise[i] ~
dnorm(0.0, taunoise)
fate[i] ~
dbin(p[i],1)
p[i]<-pow(exp(lp[i])/(1+exp(lp[i])),ed[i])
lp[i]<-b0
+ b1*buffer[i] + b2*predaor[i] + yeareffect[yr[i]] + wetlandeffect[wl[i]] +
s[i]
mu[i]<-0
}
s[1:n] ~
spatial.exp(mu[],x[],y[],tau,phi,1)
for(t in 1:nyears)
{
yeareffect[t] ~ dnorm(0.0,
tauyear)
}
tauyear~dgamma(0.1,
0.1)
sdyears <-
1/sqrt(tauyear)
for(s in
1:nwl){
wetlandeffect[s] ~ dnorm(0.0,
tauwetland)
}
tauwetland ~
dgamma(0.1,0.1)
sdwetland <-
1/sqrt(tauwetland)
}
Note, I only have problems when running the model
with the spatial effects. Otherwise, everything is fine.
Thanks in advance.
Sincerely,
-Max Post van der Burg
_____________________________
Max Post van der
Burg
Graduate Research Assistant
School of Natural Resources
University
of Nebraska- Lincoln
202 Natural Resources Hall
Lincoln, NE
68583-0819
Ph- 402-472-0508
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