I do not know how to interpret the result of:
prediction(c(1,1,0,0),
c(1,1,0,0))
prediction() functino comes from prediction {ROCR} it has this site: http://rocr.bioinf.mpi-sb.mpg.de/
The above is a working example. As per the documentation the first parameter is 'predictions' and the second 'labels' (they would be the true values).
The output is this, which I do not fully understand, specially why there is a '2' in "fp". :
An object of class "prediction" Slot "predictions": [[1]] [1] 1 1 0 0
Slot "labels": [[1]] [1] 1 1 0 0 Levels: 0 < 1
Slot "cutoffs": [[1]] [1] Inf 1 0
Slot "fp": [[1]] [1] 0 0 2