code: public void adjustBias(List<List<IN>> develData, Function<Double,Double> evalFunction, double low, double high) {
      LineSearcher ls = new GoldenSectionLineSearch(true,1e-2,low,high);
      CRFBiasedClassifierOptimizer optimizer = new CRFBiasedClassifierOptimizer(this, evalFunction);
      double optVal = ls.minimize(optimizer);
      int bi = featureIndex.indexOf(BIAS);
      System.err.println("Class bias of "+weights[bi][0]+" reaches optimial value "+optVal);
    }
docs: /*
  Adjust the bias parameter to optimize some objective function.
  Note that this function only tunes the bias parameter of one class
  (class of index 0), and is thus only useful for binary classification
  problems.