问caret:使用RFE时出现"Some row.names duplicated“警告

EN

library(caret)

################
# 1. Building dataset
################
set.seed(1)
n.samples <- 500
y <- round(runif(n = n.samples, min=0, max=1))
data <- matrix(nrow=n.samples, ncol=202)

for(i in 1:n.samples){
  toss <- runif(n=1, min=0, max=1)
  if(toss <= 0.7) {
    for(j in 1:3){
      data[i,j] <- y[i]*rnorm(n = 1, mean = i, sd = 1)
    }

    for(j in 4:6){
      data[i,j] <- rnorm(n = 1, mean = 0, sd = 1)
    }
  } else {
    for(j in 1:3){
      data[i,j] <- rnorm(n=1, mean=0, sd=1)
    }

    for(j in 4:6){
      data[i,j] <- y[i]*rnorm(n=1, mean=i-3, sd = 1) 
    }
  }

  for(j in 7:202){
    data[i,j] <- rnorm(n = 1, mean = 0, sd = 20)
  }
}

colnames(data) <- c(paste("s", 1:6, sep = ""), paste('ns', 7:202, sep=''))
rownames(data) <- paste('sample', 1:n.samples, sep='')

################
# 2. Perform SVM - RFE
################
set.seed(1)

rfe.control.settings <- rfeControl(functions = caretFuncs,
                                   method = 'boot',
                                   number = 30,
                                   verbose = TRUE)

svm.fit <- rfe(x=data, 
               y=y,
               sizes=c(1,2,3,4),
               rfeControl = rfe.control.settings,
               method = 'svmRadial') #passing options to train / caretFuncs