code: public void addUnreplicatedFactor(String factorName, T factor, VariableNumMap vars) {
      parametricFactors.add(factor);
      factorPatterns.add(new WrapperVariablePattern(vars));
      parametricFactorNames.add(factorName);
    }
docs: Adds a parameterized, unreplicated factor to the model being
  constructed. The factor will match only the variables which it is
  defined over.
  
  @param factor