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2025-01-12 00:52:51 +08:00
R Under development (unstable) (2024-04-01 r86255) -- "Unsuffered Consequences"
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Platform: x86_64-pc-linux-gnu
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> library(survival)
> aeq <- function(x, y, ...) all.equal(as.vector(x), as.vector(y), ...)
>
> # test for the "extended KM", where subjects change arms midstream
> # (I don't like it statistically, but some use it).
>
> tdata <- aml
> tdata$id <- 1:nrow(tdata)
> tdata <- survSplit(Surv(time, status) ~ ., tdata, cut= c(9, 17, 30))
> tdata$trt <- rep(c(1,1,2,2,2), length=nrow(tdata))
> # different weights for different rows of the same subject = hardest case
> tdata$wt <- rep(1:6, length= nrow(tdata))
> tdata$status[tdata$time==13] <- 1 # force at least 1 tied event
>
> # not exported, but used in byhand
> if (!exists("survflag")) survflag <- survival:::survflag
>
> byhand <- function(t1, t2, status, grp, id, wt, debug=FALSE) {
+ if (missing(wt)) wt <- rep(1, length(t1))
+ ugrp <- unique(grp)
+ ngrp <- length(ugrp)
+ out <- vector("list", ngrp)
+ names(out) <- ugrp
+ pos <- survflag(Surv(t1, t2, status), id, grp)
+ for (i in ugrp) { # create this curve
+ keep <- (grp ==i)
+ n <- sum(keep)
+ utime <- sort(unique(c(t1[keep], t2[keep])))
+ ntime <- length(utime)
+ nrisk <- ncensor <- nevent <- entry <- double(ntime)
+ surv <- cumhaz <- double(ntime)
+ U <- C <- matrix(0, n, ntime) # influence
+ U2 <- dN <- U # portions of U, useful for debugging the AUC
+ utemp <- ctemp <- double(n)
+ km <- 1.0; chaz <- 0
+ for (j in 1:ntime) {
+ atrisk <- (keep & t1 < utime[j] & t2 >= utime[j])
+ nrisk[j] <- sum(wt[atrisk])
+ nevent[j] <- sum(wt[keep & t2== utime[j] & status ==1])
+ ncensor[j] <- sum(wt[keep & t2==utime[j] & status==0 & pos >1])
+ entry[j] <- sum(wt[keep & t1== utime[j] & pos%%2 ==1])
+ if (nrisk[j] >0) {
+ km <- km * (nrisk[j]- nevent[j])/ nrisk[j]
+ chaz <- chaz + nevent[j]/nrisk[j]
+ }
+ surv[j] =km
+ cumhaz[j] =chaz
+
+ # influence
+ if (nrisk[j] > 0) {
+ haz <- nevent[j]/nrisk[j]
+ death <- (t2[keep]== utime[j] & status[keep] ==1)
+ temp <- double(n)
+ temp[death] <- 1/nrisk[j]
+ temp[atrisk[keep]] <- temp[atrisk[keep]] - haz/nrisk[j]
+ ctemp <- ctemp + temp
+ if (haz <1) utemp <- utemp - temp/(1-haz) else utemp <- 0
+ dN[death,j] <- 1/(nrisk[j]* (1-haz))
+ U2[atrisk[keep],j] <- haz/(nrisk[j] * (1-haz))
+ }
+ U[,j] <- utemp*km
+ C[,j] <- ctemp
+ }
+ out[[i]] <- list(n.id = length(unique(id[keep])), n= n,
+ time= utime, n.enter=entry, n.risk=nrisk,
+ n.event=nevent, n.censor= ncensor, surv= surv,
+ cumhaz = cumhaz, U=U, C=C, U2=U2, dN=dN)
+ }
+ out
+ }
>
> true <- with(tdata, byhand(tstart, time, status, trt, id, wt))
> ekm <- survfit(Surv(tstart, time, status) ~ trt, tdata, id=id, entry=TRUE,
+ influence= TRUE, weights=wt)
>
> aeq(ekm$n.id, unlist(lapply(true, function(x) x$n.id)))
[1] TRUE
> aeq(ekm$n, unlist(lapply(true, function(x) x$n)))
[1] TRUE
> aeq(ekm$time, unlist(lapply(true, function(x) x$time)))
[1] TRUE
> aeq(ekm$n.risk, unlist(lapply(true, function(x) x$n.risk)))
[1] TRUE
> aeq(ekm$n.enter, unlist(lapply(true, function(x) x$n.enter)))
[1] TRUE
> aeq(ekm$n.event, unlist(lapply(true, function(x) x$n.event)))
[1] TRUE
> aeq(ekm$n.censor,unlist(lapply(true, function(x) x$n.censor)))
[1] TRUE
> aeq(ekm$surv ,unlist(lapply(true, function(x) x$surv)))
[1] TRUE
>
> # The byhand function gives per-observation influence, ekm has per-subject,
> # residuals can do either, but will fail with an error for this data when
> # collapse=TRUE with a message "same id appears in multiple curves "
> rr <- residuals(ekm, times= c(9, 17, 30, 45), type="cumhaz")
> aeq(rr[tdata$trt==1,], true[[1]]$C[, match(c(9,17,30,45), true[[1]]$time)])
[1] TRUE
> aeq(rr[tdata$trt==2,], true[[2]]$C[, match(c(9,17,30,45), true[[2]]$time)])
[1] TRUE
>
> rr <- residuals(ekm, times= c(9, 17, 30, 45), type= "pstate")
> aeq(rr[tdata$trt==1,], true[[1]]$U[, match(c(9,17,30,45), true[[1]]$time)])
[1] TRUE
> aeq(rr[tdata$trt==2,], true[[2]]$U[, match(c(9,17,30,45), true[[2]]$time)])
[1] TRUE
>
> # Check influence returned by survfit
> tdata1 <- subset(tdata, trt==1)
> tdata2 <- subset(tdata, trt==2)
> inf1 <- rowsum(tdata1$wt* true[[1]]$U, tdata1$id, reorder=FALSE)
> inf2 <- rowsum(tdata2$wt* true[[2]]$U, tdata2$id, reorder=FALSE)
> aeq(inf1, ekm$influence.surv[[1]])
[1] TRUE
> aeq(inf2, ekm$influence.surv[[2]])
[1] TRUE
>
> c1 <- rowsum(tdata1$wt* true[[1]]$C, tdata$id[tdata$trt==1], reorder=FALSE)
> c2 <- rowsum(tdata2$wt* true[[2]]$C, tdata$id[tdata$trt==2], reorder=FALSE)
> aeq(c1, ekm$influence.chaz[[1]])
[1] TRUE
> aeq(c2, ekm$influence.chaz[[2]])
[1] TRUE
>
> # Look at the AUC
> t1 <- true[[1]]
> width <- diff(c(t1$time, 50))
> aucr <- width* t1$surv # the rectangles that make up auc(50)
> ainf <- t1$U %*% diag(width) # row i= influence of obs i on each rectangle
> aucinf <- t(apply(ainf,1,cumsum))
>
> rr <- residuals(ekm, times= c(t1$time[-1], 50), type= "auc")
> aeq(rr[tdata$trt==1,], aucinf)
[1] TRUE
>
> # use factor(status) to force the multi-state code
> ekm2 <- survfit(Surv(tstart, time, factor(status)) ~ trt, tdata, id=id,
+ entry=TRUE, influence= TRUE, weights=wt)
>
> aeq(ekm$n, ekm2$n)
[1] TRUE
> aeq(ekm$time, ekm2$time)
[1] TRUE
> aeq(ekm$n.risk, ekm2$n.risk[,1])
[1] TRUE
> aeq(ekm$n.event, ekm2$n.event[,2])
[1] TRUE
> aeq(ekm$n.censor, ekm2$n.censor[,1])
[1] TRUE
> aeq(ekm$n.enter, ekm2$n.enter[,1])
[1] TRUE
> aeq(ekm$surv, ekm2$pstate[,1])
[1] TRUE
> aeq(ekm$std.err, ekm2$std.err[,1])
[1] TRUE
> aeq(ekm$cumhaz, ekm2$cumhaz[,1])
[1] TRUE
> aeq(ekm$std.chaz, ekm2$std.chaz[,1])
[1] TRUE
> aeq(ekm$strata, ekm2$strata)
[1] TRUE
> aeq(ekm$n.id, ekm2$n.id)
[1] TRUE
> aeq(ekm$counts,
+ ekm2$counts[,c("nrisk:1", "ntrans:1.2", "ncensor:1", "nenter:1")])
[1] TRUE
> aeq(ekm$influence.surv[[1]], ekm2$influence.pstate[[1]][,,1])
[1] TRUE
> aeq(ekm$influence.surv[[2]], ekm2$influence.pstate[[2]][,,1])
[1] TRUE
>
>
> proc.time()
user system elapsed
0.971 0.071 1.034