About using opf to do cpf

[asd6418]

Dear all,

     I am wondering if it is possible to use opf's user-define variable to 
calculate lambda in cpf?
     Such as 

                 max lambda
                 F(x, lambda) = 0

     And where can I find the example of user-define function? It's not that
helpful by reading the manual. 

                                                  Regards,
                                                         LarryHo