The initial state SDs are assumed to follow half-Cauchy priors, C+(0,A), where the SDs may be common or distinct among the states.
initEvol0(mu0, commonSD = TRUE)List of relevant components:
the p x 1 evolution error SD sigma_w0,
the p x 1 parameter-expanded RV's px_sigma_w0,
and the corresponding global scale parameters
sigma_00 and px_sigma_00 (ignore if commonSD)
p x 1 vector of initial values (undifferenced)
logical; if TRUE, use common SDs (otherwise distinct)
This function initializes the parameters for a PX-Gibbs sampler.