code: @Override
      public double getValue(int idx) {
          int vSize = MVecArray.count(varBeliefs);
          if (idx < vSize) {
              return MVecArray.getValue(idx, varBeliefs);
          } else {
              return MVecArray.getValue(idx - vSize, facBeliefs);
          }
      }
docs: Gets a particular value by treating this object as a vector.
  
  NOTE: This implementation is O(n).
  
  @param idx The index of the value to get.
  @return The value at that index.