[R] AUC calculated from Epi package

[array chip]

Hi, I have a dataset (see attached) with 2 variables "Y" is binary, "x" is a 
continuous variable. I want to calculate area under the curve (AUC) for the ROC 
curve, but I got different AUC values using ROC() from Epi package vs. 
rcorr.cens() from rms package:

test<-read.table("test.txt",sep='\t',header=T,row.names=NULL)
y<-test$y
x<-test$x
library(Epi)
ROC(form=y~x,plot="ROC")

library(rms)
rcorr.cens(x,y)
lrm(y~x)

As you can see, ROC() gave an AUC 0.782, while both rcorr.cens() and lrm() 
(C-index) gave AUC 0.813. That's a big difference. And I believe rms package 
gave me correct answer. But anyone have any clue about the difference?

Thanks

John
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