R/IntegratedAUC.R

In survAUC: Estimators of Prediction Accuracy for Time-to-Event Data

##############################################################
## Integrated AUC
##############################################################
# AUC	- vector of AUC's
# times	- vector of times
# S		- vector of survival probability
# tmax	- maximum timepoint



IntAUC <- function(AUC, times, S, tmax, auc.type="cumulative")
{
	n_S <- length(S)
	n_AUC <- length(AUC)
	n_times <- length(times)
	if(!((n_S == n_AUC) && (n_AUC == n_times)))
		stop("AUC, times and S must be the same length!")
	auc.type <- charmatch( auc.type, c("cumulative","incident") )
	if (is.na(auc.type))
		stop("auc.type must be one of 'cumulative' or 'incident'")
	maxI <- sum( times <= tmax )
	ind_S <- S[min(maxI+1,length(S))]
	iAUC <- .C(`C_int_auc`,
			   as.numeric(AUC),
			   as.numeric(times),
			   as.numeric(S),
			   as.numeric(tmax),
			   as.integer(n_S),
			   as.integer(maxI),
			   as.numeric(ind_S),
			   as.integer(auc.type-1),
			   as.numeric(0))
	#No longer needed since the symbol is registered in the NAMESPACE
	#          ,PACKAGE="survAUC")
	iAUC[[9]]
}