docs: private void updateMinMax(NumberVector featureVector, double[] minima, double[] maxima) {
      assert (minima.length == featureVector.getDimensionality());
      for(int d = 0; d < featureVector.getDimensionality(); d++) {
        double v = featureVector.doubleValue(d);
        if(v == v) { // Avoid NaN.
          maxima[d] = MathUtil.max(v, maxima[d]);
          minima[d] = MathUtil.min(v, minima[d]);
        }
      }
    }