Returns the area under the curve ("AUC") of a receiver-operating characteristic curve for the given predicted and actual values.
auc(actual, pred)Logical vector: TRUE for positive class.
If not a logical vector, the result is interpreted as one if safe to do so,
viz. if actual contains precisely two unique values and is either a numeric vector,
an ordered factor, or the unique values are FALSE and TRUE (case-insensitively).
Anything else is an error.
Numeric (double) vector the same length as actual giving the predicted probability of TRUE. Must be a numeric vector the same length as actual.