code: public PlateFactor getFactorByName(String name) {
      int index = factorNames.indexOf(name);
      if (index == -1) {
        return null;
      } else {
        return plateFactors.get(index);
      }
    }
docs: Gets the factor in this factor graph with the given {@code name}.
  Returns {@code null} if no factor is called {@code name}.
  
  @param name
  @return