Tuesday, December 25, 2012

No error message

I have posted regularly about poor error messages from software. In general I find that the importance of formulating meaningful  error messages is underestimated by developers, leading to some level of frustration by users. Of course, issuing no error message at all is even easier for a developer (and even more difficult for users to deal with).

               S O L V E      S U M M A R Y

     MODEL   LANDfeas            OBJECTIVE  totallow
     TYPE    LP                  DIRECTION  MINIMIZE
     SOLVER  MOSEK               FROM LINE  165233

**** SOLVER STATUS     4 Terminated By Solver     
**** MODEL STATUS      14 No Solution Returned    
**** OBJECTIVE VALUE                0.0000

RESOURCE USAGE, LIMIT         20.311    900000.000
ITERATION COUNT, LIMIT         0        900000

    Copyright (C)   MOSEK ApS, Fruebjergvej 3, Box 16
                    DK-2100 Copenhagen, Denmark
GAMS/MOSEK Extended license detected

No solution returned

I received a listing file with this fragment. I have no idea how I can help the user as I have no idea what went wrong. Now I need to get the model and data files and see if I can reproduce the problem. We see some strange trade-offs at work here: the developers saved some time by not providing code to print a readable message, and as a result (multiple) users have to spent extra time and effort in supporting and maintaining an application.