public AbstractConfirmatoryFactorAnalysisEstimator(
     ConfirmatoryFactorAnalysisModel model, RealMatrix varcov, double numberOfExaminees) {
   this.model = model;
   this.varcov = varcov;
   this.numberOfExaminees = numberOfExaminees;
   this.nItems = model.getNumberOfItems();
   LUDecomposition CVLUD = new LUDecomposition(varcov);
   VCinv = CVLUD.getSolver().getInverse();
 }