Grouping People On Preference

The need of solver is to optimize the solution - there maybe (likely are) ways to do this sub-optimal using more by hand methods or through VBA programming but solver is your easiest bet. The weights add to complexity but not significantly (from my understanding of linear programming).

With the number down to 120 campers and 12 cabins you have 1440 variable cells so the paid version of solver should work (depending on how many times this needs to be done the 15 day trial may be enough). However, the solver paid version is $1,000 so it is likely cost prohibitive for just this exercise.

Currently you could set the weights all to one and have campers choose preference from 0-3 so if you only have one or two preferences you only enter one or two preferences and essentially remove weighting. The real limitations you are facing is the number of campers that need to be assigned. With actually camper preferences, you could make smaller problems that only handle groups of campers who have requests that are tied to each other but the free version limits you to 20 campers and 10 cabins at a time (200 variables) which is fairly small and could likely be done by hand.

I have attached the smaller version assuming half male and half female (you would copy and run twice for each set) - I also removed the weighting. However, the problem still exists with the 1440 decision variables. If you have real data I would be happy to setup my solver trial and try and run it to check results.

Sorry for the rambling post and happy to help.

- melk