Receiver operating characteristic of all descriptor combinations. Receiver operating characteristic (ROC) for all descriptor combinations. Corresponding AUC is given in brackets. ROC curves were computed by a 5-fold cross-validation on the training data set using plotroc.py of the libsvm 2.8 package  after an optimal SVM parameter set was chosen by grid.py. True positive and false positive rates are calculated by interpreting the SVM decision values. Prediction accuracies as plotted here are larger compared to accuracies in Table 1 as even though cross-validation ensures that training and testing is done on different alignments some sequences may occur in the training as well as in the test alignments. In contrast, accuracies in Table 1 are based on test alignments which do not contain any sequence attending at a training alignment.