/** * return a new feature vector for a + b * * @param a * @param b * @return */ public static FeatureVector plus(FeatureVector a, FeatureVector b) { FeatureVector fv = null; List<FeatureItem> af = convert2SortedFeatureNodeArray(a); List<FeatureItem> bf = convert2SortedFeatureNodeArray(b); Pair<int[], double[]> p = plus(af, bf); fv = new FeatureVector(p.getFirst(), p.getSecond()); return fv; }