coxinterval (version 1.2)

maximalint: Find maximal intersections from an interval-type survival object

Description

A utility function that returns the "maximal intersections" from a set of censoring intervals in a given type = "interval" or type = "interval2" Surv object.

Usage

maximalint(x, eps = 1e-7)

Arguments

x

a two-column matrix or data frame giving the left- and right-endpoints of the censoring intervals or, alternatively, a type = "interval" or type = "interval2" Surv object. Following the type = "interval2" format, any NA-valued right endpoints are considered the same as Inf.

eps

a small value used to break ties in maximal intersection endpoints. Note that a large time scale requires a larger epsilon in order to ensure that t != t + eps for a given time value t.

Value

int

a two-column matrix whose rows give the maximal intersections (Wong and Yu, 1999) of the censoring intervals represented in x

ind

a nrow(x) by nrow(int) matrix that indicates overlap between each maximal intersection and censoring interval

Details

Each censoring interval is assumed to exclude its left endpoint. Analogous to Maathuis (2005, Section 2.1) ties between the unique (open) left and (closed) right endpoints among the censoring intervals are broken by subtracting a small value from the right endpoint value before constructing the maximal intersections.

References

Maathuis, MH (2005) Reduction algorithm for the NPMLE for the distribution function of bivariate interval-censored data. Journal of Computational and Graphical Statistics 14, 352--362.

Wong, GYC. and Yu, Q. (1999) Generalized MLE of a joint distribution function with multivariate interval-censored data. Journal of Multivariate Analysis 69, 155--166.

Examples

s <- with(cosmesis[1:10, ], Surv(left, right, type = "interval2"))
s
maximalint(s)