  bioUInt config = 1 + (gradient)?1:0 + (hessian)?1:0 ;
  if (recycle == config && theDerivatives != NULL) {
    if (gradient || hessian) {
      if (theDerivatives->getSize() == literalIds.size()) {
	return theDerivatives ;
      }
    }
    else {
      //    DEBUG_MESSAGE("Plus - Recycled: " << str.length() << " = " << theDerivatives->f) ;
      return theDerivatives ;
    }
  }
  recycle = config ; 
