s_gompertz: Factory of SURVIVAL objects with Gompertz distributions

In survobj: Simulate Parametric and Semi-Parametric Survival Times with Object-Oriented Design

Factory of SURVIVAL objects with Gompertz distributions

Description

Creates a SURVIVAL object with a Gompertz distribution.

Usage

s_gompertz(...)

Arguments

...	Parameters to define the distribution. See the Parameters for details

Value

a SURVIVAL object of the Gompertz distribution family. See the documentation of s_factory for the methods available for SURVIVAL objects

Parameters

To create a Gompertz survival object the following options are available:

scale and shape to specify the canonical parameters of the distribution, or

surv, t and shape for the proportion surviving (no events) at time t and shape, or

fail and t and shape for the proportion failing (events) at time t and shape.

scale = -log(surv)·shape/(exp(shape·t))

scale = -log(1-fail)·shape/(exp(shape·t))

The parameters should be spelled correctly as partial matching is not available

Negative shape

A negative shape produces a decreasing hazard whose cumulative hazard is bounded above by scale / abs(shape) (following Bender, Augustin & Blettner 2005). This makes the distribution improper: a cure fraction of exp(-scale / abs(shape)) of the subjects never experience the event, so their simulated survival time (rsurv, rsurvhr, rsurvaft, rsurveh) and invCum_Hfx() are returned as Inf.

Examples

s_gompertz(scale = 1, shape = 1.5)
s_gompertz(surv = 0.4, t = 2, shape = 1.5)
s_gompertz(fail = 0.6, t = 2, shape = 1.5)

survobj documentation built on Sept. 21, 2026, 1:07 a.m.