code: public void learn(RNNSearch<double[], double[]> range, double[][] samples, double radius, int Nz) {
          learn(range, samples, radius, Nz, 0.2);
      }
docs: Train the posteriori multiple probe algorithm.
  @param range the neighborhood search data structure.
  @param radius the radius for range search.
  @param Nz the number of quantized values.