docs: private double computeExplainedVariance(double[] eigenValues, int filteredEigenPairs) {
      double strongsum = 0., weaksum = 0.;
      for(int i = 0; i < filteredEigenPairs; i++) {
        strongsum += eigenValues[i];
      }
      for(int i = filteredEigenPairs; i < eigenValues.length; i++) {
        weaksum += eigenValues[i];
      }
      return strongsum / (strongsum + weaksum);
    }