code: private void updateSetsLabeled(int i1, final double a1, final double C)
      {
          final double y_i = label[i1];
          I1[i1] = a1 == 0 && y_i == 1;
          I2[i1] = a1 == C && y_i == -1;
          I3[i1] = a1 == C && y_i == 1;
          I4[i1] = a1 == 0 && y_i == -1;
      }
docs: Updates the index sets
  @param i1 the index to update for
  @param a1 the alphas value for the index
  @param C the regularization value to use for this datum