/** * Returns an explanation for the normalized term frequency. * * <p>The default normalization methods use the field length of the document and the average field * length to compute the normalized term frequency. This method provides a generic explanation for * such methods. Subclasses that use other statistics must override this method. */ public Explanation explain(BasicStats stats, float tf, float len) { Explanation result = new Explanation(); result.setDescription(getClass().getSimpleName() + ", computed from: "); result.setValue(tfn(stats, tf, len)); result.addDetail(new Explanation(tf, "tf")); result.addDetail(new Explanation(stats.getAvgFieldLength(), "avgFieldLength")); result.addDetail(new Explanation(len, "len")); return result; }