inst/examples/Ex_rGamma_reg.R

In glmbayes: Bayesian Generalized Linear Models (IID Samples)

############################### Start of rGamma_reg examples ####################
## During CRAN checks, run examples sequentially.
use_parallel <- identical(Sys.getenv("NOT_CRAN"), "true")

## Annette Dobson (1990) "An Introduction to Generalized Linear Models".
## Page 9: Plant Weight Data.
ctl <- c(4.17, 5.58, 5.18, 6.11, 4.50, 4.61, 5.17, 4.53, 5.33, 5.14)
trt <- c(4.81, 4.17, 4.41, 3.59, 5.87, 3.83, 6.03, 4.89, 4.32, 4.69)
group <- gl(2, 10, 20, labels = c("Ctl", "Trt"))
weight <- c(ctl, trt)

## Set up prior hyperparameters (shape/rate) and model matrix via Prior_Setup
ps <- Prior_Setup(weight ~ group, family = gaussian())
y <- ps$y
x <- as.matrix(ps$x)

## rGamma_reg uses a dGamma-style prior on dispersion with fixed beta.
## Use coefficients from Prior_Setup (full-model GLM MLE by default).
prior_list <- list(beta = ps$coefficients, shape = ps$shape, rate = ps$rate)

out <- rGamma_reg(n = 1000, y = y, x = x, prior_list = prior_list,
  family = gaussian(), use_parallel = use_parallel)
summary(out)