public void normalizeProbabilities() {
        double sum = 0.0;
        for (Children c : childTrees) {
            sum += c.getProbability();
        }
        double coeff = 1.0 / sum;

        for (Children childTree : childTrees) {
            double newProb = childTree.getProbability() * coeff;
            childTree.setProbability(newProb);
        }
    }
Normalizes all probabilities between 0.0 (inclusive) and 1.0 (exclusive).
document/src/main/java/com/yahoo/document/annotation/AlternateSpanList.java