lik_pois: Likelihood object for Poisson error distribution
Description
Creates a likelihood object for ash for use with Poisson error distribution
Usage
lik_pois(y, scale = 1, link = c("identity", "log"))
Arguments
y
Poisson observations.
scale
Scale factor for Poisson observations: y~Pois(scale*lambda).
link
Link function. The "identity" link directly puts unimodal prior on Poisson
intensities lambda, and "log" link puts unimodal prior on log(lambda).
Details
Suppose we have Poisson observations y where \(y_i\sim Poisson(c_i\lambda_i)\).
We either put an unimodal prior g on the (scaled) intensities \(\lambda_i\sim g\)
(by specifying link="identity") or on the log intensities
\(log(\lambda_i)\sim g\) (by specifying link="log"). Either way,
ASH with this Poisson likelihood function will compute the posterior mean of the
intensities \(\lambda_i\).