calibrate_survival: Calibrate a Weibull survival curve to target points

In simulab: Simulates a Wide Variety of Data Shapes, Sizes and Distributions

Calibrate a Weibull survival curve to target points

Description

Finds the formula and shape whose simstudy Weibull curve, S(t) = exp(-exp(formula) * t^(1 / shape)) with scale fixed at 1, passes as closely as possible through the supplied points. The fit is a least-squares fit of log(time) on log(-log(survival)), run with L-BFGS-B, and the returned formula and shape can be handed straight to define_survival() or survival_curve().

Usage

calibrate_survival(time, survival)

Arguments

time	Increasing positive times. A finite numeric vector of at least two strictly increasing values, the same length as survival.
survival	Survival probabilities at those times. A finite numeric vector strictly inside ⁠(0, 1)⁠ and strictly decreasing.

Value

A one-row base data.frame with the calibrated numeric formula and shape, the optim() convergence code (always 0, since a non-converged fit raises an error), and rmse, the root mean squared residual on the log-time scale.

Examples

calibrate_survival(time = c(50, 100, 150), survival = c(0.9, 0.7, 0.4))

simulab documentation built on Oct. 15, 2026, 5:08 p.m.