2025-01-12 00:52:51 +08:00

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R Under development (unstable) (2024-04-17 r86441) -- "Unsuffered Consequences"
Copyright (C) 2024 The R Foundation for Statistical Computing
Platform: aarch64-unknown-linux-gnu
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> library(survival)
> aeq <- function(x,y, ...) all.equal(as.vector(x), as.vector(y), ...)
> #
> # Test the multi-state version of the CI curve
> #
> tdata <- data.frame(id=c(1,1,1,1, 2,2,2, 3,3, 4,4,4,4, 5, 6, 6),
+ time1=c(0, 10,20,30, 0, 5, 15, 0, 20, 0, 6,18,34, 0, 0,15),
+ time2=c(10,20,30,40, 5, 15,25, 20, 22, 6,18,34,50,10,15,20),
+ status=c(1,1,1,1, 1,1,1, 1,0, 1,1,1,0,0,1,0),
+ event= letters[c(1,2,3,4, 2,4,3, 2,2, 3,1,2,2,1, 1,1)],
+ wt = c(2,2,2,2, 1,1,1, 3,3, 1,1,1,1, 2, 1,1),
+ stringsAsFactors=TRUE)
> tdata$stat2 <- factor(tdata$status * as.numeric(tdata$event),
+ labels=c("censor", levels(tdata$event)))
>
> fit <- survfit(Surv(time1, time2, stat2) ~1, id=id, weights=wt, tdata,
+ influence=TRUE)
>
> # The exact figures for testci2.
> # The subject data of id, weight, (transition time, transition)
>
> #1: 2 (10, 0->a) (20, a->b) (30, b->c) (40, c->d) no data after 40=censored
> #2: 1 ( 5, 0->b) (15, b->d) (25, d->c) no data after 25 implies censored then
> #3: 3 (20, 0->b) (22, censor)
> #4: 1 ( 6, 0->c) (18, c->a) (34, a->b) (50, censor)
> #5: 2 (10, censor)
> #6: 1 (15, 0->a) (20, censor)
>
> # Each line below follows a subject through time as a (state, rdist weight) pair
> # using the redistribute to the right algorithm.
> # RDR algorithm: at each censoring (or last fu) a subject's weight is put into
> # a "pool" for that state and their weight goes to zero. The pool is
> # dynamically shared between all members of the state proportional to their
> # original case weight, when someone leaves they take their portion of the
> # pool to the new state.
>
> # Table of case weights and state, blank is weight of zero
> # time 5 6 10 15 18 20 25 30 34 40 50
> # -----------------------------------------------------------------------
> # id, wt
> # 1, 2 - - a a a b b c c d
> # 2, 1 b b b d d d c
> # 3, 3 - - - - - b
> # 4, 1 - c c c a a a a b b b
> # 5, 2 - - -
> # 6, 1 - - - a a a
>
> # Pool weights
> # 10 10+ 15 18 20 20+ 22+ 25 25+ 30 34 40 40+
> # - 0 2 3/2 3/2 0
> # a 0 0 1/2 1/2 1/4 5/4 5/4 5/4 5/4 5/4
> # b 0 0 0 0 7/4 7/4 19/4 19/4 19/4 5/4 5/4 5/4
> # c 0 0 0 0 0 1 23/4 23/4
> # d 0 0 0 0 0 23/4 31/4
>
> # fit$pstate for time i and state j = total weight at that time/state in the
> # above table (original weight + redistrib), divided by 10.
>
> # time 5 6 10 15 18 20 25 30 34 40 50
> truth <- matrix(c(0, 0, 2, 3, 4, 2, 1, 1, 0, 0, 0,
+ 1, 1, 1, 0, 0, 5, 2, 0, 1, 1, 1,
+ 0, 1, 1, 1, 0, 0, 1, 2, 2, 0, 0,
+ 0, 0, 0, 1, 1, 1, 0, 0, 0, 2, 0) +
+ c(0, 0, 0, .5, .5, 1/4, 5/4, 5/4, 0, 0, 0,
+ 0, 0, 0, 0, 0, 7/4, 19/4, 0, 5/4, 5/4, 5/4,
+ 0, 0, 0, 0, 0, 0, 0, 23/4, 23/4, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 23/4, 31/4),
+ ncol=4)
> truth <- truth[c(1:6, 6:11),]/10 #the explicit censor at 22
>
> #dimnames(truth) <- list(c(5, 6, 10, 15, 18, 20, 25, 30, 34, 40, 50),
> # c('a', 'b', 'c', 'd')
> aeq(truth, fit$pstate[,2:5])
[1] TRUE
>
> # Test the dfbetas
> # It was a big surprise, but the epsilon where a finite difference approx to
> # the derivative is most accurate is around 1e-7 = approx sqrt(precision).
> # Smaller eps makes the approximate derivative worse.
> # There is a now a formal test in mstate.R, not approximate.
>
> # compute the per observation influence first
> n <- nrow(tdata)
> U <- array(0, dim=c(n, dim(fit$pstate)))
> eps <- sqrt(.Machine$double.eps)
> n <- nrow(tdata)
> for (i in 1:n) {
+ twt <- tdata$wt
+ twt[i] <- twt[i] + eps
+ tfit <- survfit(Surv(time1, time2, stat2) ~ 1, id=id, tdata,
+ weights=twt)
+ U[i,,] <- (tfit$pstate - fit$pstate)/eps #finite difference approx
+ }
> dfbeta <- rowsum(tdata$wt*matrix(U,nrow=n), tdata$id) # per subject
> dfbeta <- array(dfbeta, dim=c(6,12,5))
> aeq(dfbeta, fit$influence, tolerance= eps*10)
[1] TRUE
>
> aeq(fit$std.err, sqrt(apply(fit$influence.pstate^2, 2:3, sum)))
[1] TRUE
>
> if (FALSE) {
+ # a plot of the data that helped during creation of the example
+ plot(c(0,50), c(1,6), type='n', xlab='time', ylab='subject')
+ with(tdata, segments(time1, id, time2, id))
+ with(tdata, text(time2, id, as.numeric(stat2)-1, cex=1.5, col=2))
+ }
>
> if (FALSE) {
+ # The following lines test out 4 error messages in the routine
+ #
+ # Gap in follow-up time, id 2
+ survfit(Surv(c(0,5,9,0,5,0), c(5,9,12, 4, 6, 3), factor(c(0,0,1,1,0,2))) ~1,
+ id=c(1,1,1,2,2,3))
+ # mismatched weights
+ survfit(Surv(c(0,5,9,0,5,0), c(5,9,12, 5, 6, 3), factor(c(0,0,1,1,0,2))) ~1,
+ id=c(1,1,1,2,2,3), weights=c(1,1,2,1,1,4))
+ # in two groups at once
+ survfit(Surv(c(0,5,9,0,5,0), c(5,9,12, 5, 6, 3), factor(c(0,0,1,1,0,2))) ~
+ c(1,1,2,1,1,2), id=c(1,1,1,2,2,3))
+ # state change that isn't a state change (went from 1 to 1)
+ survfit(Surv(c(0,5,9,0,5,0), c(5,9,12, 5, 6, 3), factor(c(0,1,1,1,0,2))) ~1,
+ id=c(1,1,1,2,2,3))
+ }
>
> # Check the start.time option
> #
> # Later work showed this test has to be false. At time 0 everyone starts in
> # state (s0), but by time 20 many have shifted to another. fit2 picks up at
> # the right place, but because there is no istate varaible, fit2x starts
> # everyone in (s0) at time 20. There is no way for survfit to know.
> if (FALSE) {
+ fit2 <- survfit(Surv(time1, time2, stat2) ~1, id=id, weights=wt, tdata,
+ start.time=20)
+ data2 <- subset(tdata, time2>= 20)
+ fit2x <- survfit(Surv(time1, time2, stat2) ~1, id=id, weights=wt, data2)
+
+ ii <- names(fit2)[!(names(fit2) %in% c("call", "start.time"))]
+ all.equal(unclass(fit2)[ii], unclass(fit2x)[ii])
+ }
>
> proc.time()
user system elapsed
0.423 0.024 0.444