Hi everyone,
I'm trying to estimate the scale parameter of a gamma distribution considering a link function with covariables as the shape parameter, but I have a problem with the logGamma function, apparently the obtained values for this function are negative, I have tried changing the initial values of the parameters and the values of the prior distributions but the problem is still the same
I would really appreciate if there is any suggestion to make this work
Here is the code with the data
model{
for(i in 1:n)
{
for(j in 1:m)
{
x[i,j] ~ dgamma(alpha.1[i,j], beta)
alpha.1[i,j]<-beta1*exp(beta2*T[j])*exp(beta3*Vi[j])
}
}
beta ~ dgamma(0.01, 0.01)
beta1 ~ dnorm(0.0, 0.0000001)
beta2 ~ dnorm(0.0, 0.0000001)
beta3 ~ dnorm(0.0, 0.0000001)
}
#Inits
inits=list(beta= 1, beta1=1, beta2=1, beta3=1)
#Data
list(T=c(0.364,0.545,0.727,0.773,0.909,1,0.818),
Vi=c(1,1,1,1,1,1,1), n=15, m=7,
x= structure(
.Data = c(
0.0141, 0.0182, 0.0016, 0.0021, 0.0089, 0.009, 0.002,
0.0031, 0.0172, 0.0075, 0.0011, 0.0024, 0.0025, 0.008,
0.11, 0.0069, 0.007, 0.03, 0.0001, 0.0001, 0.0001,
0.003, 0.002, 0.008, 0.003, 0.0005, 0.0006, 0.009,
0.001, 0.0121, 0.0008, 0.0031, 0.0005, 0.0005, 0.001,
0.011, 0.005, 0.0009, 0.0261, 0.0084, 0.0085, 0.0022,
0.017, 0.0012, 0.0007, 0.0001, 0.0015, 0.0016, 0.001,
0.0259, 0.0161, 0.0104, 0.0105, 0.012, 0.0001, 0.0001,
0.003, 0.008, 0.0051, 0.0719, 0.0009, 0.0009, 0.0003,
0.008, 0.0012, 0.0159, 0.0319, 0.0105, 0.0106, 0.002,
0.014, 0.0043, 0.0728, 0.0549, 0.0015, 0.0016, 0.003,
0.006, 0.001, 0.012, 0.002, 0.0035, 0.0036, 0.0099,
0.021, 0.0008, 0.0013, 0.0163, 0.0033, 0.0034, 0.008,
0.005, 0.001, 0.002, 0.005, 0.004, 0.004, 0.008,
0.0004, 0.001, 0.0011, 0.0012, 0.0004, 0.0005, 0.0039),
.Dim = c(15, 7)))
Thanks in advance & have a great day
Luis Rodriguez
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