public class MeanAbsError implements OnlineUpdate.Function{
private static final double TETTA = 0.01;
private DoubleVector zeroVector = null;
@Override
public OutputStructure compute(InputStructure e) {
OutputStructure res = new OutputStructure();
int rank = e.user.getVector().getLength();
if (zeroVector == null) {
zeroVector = new DenseDoubleVector(rank, 0);
}