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genrocdata <- function(inputFile, classLabels)
{
noRuns = 100 ;
data = read.table(inputFile, header=T) ;
colBegin = which(colnames(data) == classLabels[1]) ;
colEnd = colBegin + length(classLabels) - 1 ;
sensitivity <- array(dim=c(noRuns, length(classLabels))) ;
specificity <- array(dim=c(noRuns, length(classLabels))) ;
for ( i in 1:noRuns )
{
classificationMatrix = as.matrix(data[(3*i - 2):(3*i), colBegin:colEnd]) ;
for ( j in 1:nrow(classificationMatrix) )
{
truePositive = classificationMatrix[j,j] ;
falsePositive = sum(classificationMatrix[j,]) - truePositive ;
falseNegative = sum(classificationMatrix[,j]) - truePositive ;
trueNegative = sum(classificationMatrix) - (truePositive + falsePositive + falseNegative) ;
sensitivity[i, j] = truePositive / ( truePositive + falseNegative) ;
specificity[i, j] = trueNegative / ( falsePositive + trueNegative) ;
}
}
ret = data.frame(sens=sensitivity, spec=specificity) ;
fileName = strsplit(inputFile, "\\.dat") ;
output = paste(fileName[[1]], ".roc.dat", sep="") ;
write.table(ret, output, row.names=F) ;
}
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