R/dfoldedt.R

In foldedt: The Folded t Family of Distributions

dfoldedt <- function(y, mu, s2, v, logged = FALSE) {
   con <- gamma(0.5 * (v + 1) ) / gamma(0.5 * v) / sqrt(v * pi * s2)
   a1 <- 1 + (y - mu)^2 / (v * s2)
   a2 <- 1 + (y + mu)^2 / (v * s2)
   f <- con * ( a1^( -0.5 * (v+1) ) + a2^( -0.5 * (v+1) ) )
   if ( logged )  f <- log(f)
}