surv {Countr}

R Documentation

Wrapper to built in survival functions

Description

Wrapper to built in survival functions

Usage

surv(t, distPars, dist)

Arguments

t	double, time point where the survival is to be evaluated at.
distPars	Rcpp::List with distribution specific slots, see details.
dist	character name of the built-in distribution, see details.

Details

The function wraps all builtin-survival distributions. User can choose between the weibull, gamma, gengamma(generalized gamma) and burr (Burr type XII distribution). It is the user responsibility to pass the appropriate list of parameters as follows:

weibull

scale (the scale) and shape (the shape) parameters.

burr

scale (the scale) and shape1 (the shape1) and shape2 (the shape2) parameters.

gamma

scale (the scale) and shape (the shape) parameter.

gengamma

mu (location), sigma (scale) and Q (shape) parameters.

Value

a double giving the value of the survival function at time point t at the parameters' values.

Examples

tt <- 2.5
## weibull

distP <- list(scale = 1.2, shape = 1.16)
alpha <- exp(-log(distP[["scale"]]) / distP[["shape"]])
pweibull(q = tt, scale = alpha, shape = distP[["shape"]],
                      lower.tail = FALSE)
surv(tt, distP, "weibull") ## (almost) same

## gamma
distP <- list(shape = 0.5, rate = 1.0 / 0.7)
pgamma(q = tt, rate = distP[["rate"]], shape = distP[["shape"]],
                    lower.tail = FALSE)
surv(tt, distP, "gamma")  ## (almost) same

## generalized gamma
distP <- list(mu = 0.5, sigma = 0.7, Q = 0.7)
flexsurv::pgengamma(q = tt, mu = distP[["mu"]],
                    sigma = distP[["sigma"]],
                    Q = distP[["Q"]],
                    lower.tail = FALSE)
surv(tt, distP, "gengamma")  ## (almost) same

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