RM Item Sim

        if (method == Method.ITEM_SIMILARITY) {
            SimilarityTable ISim = itemNeighbors.get(item);
            int detail = numItemNeighbors;
            for (SimilarityTable.Similarity s : ISim.similarities){
                Rating r = raterData.get(rater).getRatingFor(s.key);
                if (r == null) continue;
                numer += s.predict(r.rawScore) * s.value;
                denom += s.value;
                ct++;
                if (ct >= detail) break;
            }
            if (denom != 0)
                score = numer / denom;
            else
                score = geometricMeanBaseline(rater, item);
        }