# Saddlepoint approximation of the density function of the # GAL distribution # # Author: Francois Pelletier # # LGPL 3.0 ############################################################################### #' Saddlepoint approximation of the density function of the #' GAL distribution #' @param x vector of quantiles #' @param param Parameter vector #' @param eval.time Time of the process #' @param type Choose between "mu" or "kappa" parametrization #' @param log Logical for log-parameters #' @export dsaddleapproxGAL #' @return Saddlepoint approximation of the density function #' @author Francois Pelletier dsaddleapproxGAL <- function(x,param,eval.time=1,type="mu",log=FALSE) { s <- saddlepointGAL(x,param,eval.time,type,log) 1/sqrt(2*pi*diffcgfGAL(s,2,param,eval.time,type,log)) * exp(cgfGAL(s,param,type,log)-s*x) }