private static void readData() {
		try {
			b = new BufferedReader(new FileReader(fileDirectory + dataFile));
			String line;
			while ((line = b.readLine()) != null) {
				String[] s = line.split(":");
				int usr = Integer.parseInt(s[0]);
				int mov = Integer.parseInt(s[2]);
				int rat = Integer.parseInt(s[4]);

				if (UserMovieRatings.containsKey(usr)) {
					UserMovieRatings.get(usr).put(mov, rat);
				} else {
					HashMap<Integer, Integer> ratings = new HashMap<Integer, Integer>();
					ratings.put(mov, rat);
					UserMovieRatings.put(usr, ratings);
				}
				if (ratingsByMovie.containsKey(mov)) {
					ratingsByMovie.get(mov).add((double) rat);
				} else {
					ArrayList<Double> ratings = new ArrayList<Double>();
					ratings.add((double) rat);
					ratingsByMovie.put(mov, ratings);
				}
				if (usersByMovie.containsKey(mov)) {
					usersByMovie.get(mov).add(usr);
				} else {
					HashSet<Integer> raters = new HashSet<Integer>();
					raters.add(usr);
					usersByMovie.put(mov, raters);
				}
			}
			b.close();
		} catch (FileNotFoundException e) {
			System.err.println("Couldn't read the parameter file. Check the file name: " + dataFile);
			e.printStackTrace();
		} catch (IOException ioe) {
			ioe.printStackTrace();
		}

	}