public:

     virtual void _messageLevel(MessageLevel level);

     void _applyMessageLevel();

     ///Enum for \c messageLevel() parameter

     int _message_level;

     enum MessageLevel {

       /// no output (default value)

       MESSAGE_NO_OUTPUT = 0,

       /// error messages only

       MESSAGE_ERROR_MESSAGE = 1,

       /// normal output

       MESSAGE_NORMAL_OUTPUT = 2,

       /// full output (includes informational messages)

       MESSAGE_FULL_OUTPUT = 3

     };

   private:

     MessageLevel _message_level;

   public:

     ///Set the verbosity of the messages

     ///Set the verbosity of the messages

     ///

     ///\param m is the level of the messages output by the solver routines.

     void messageLevel(MessageLevel m);