Assigning people to beds - approaches to automate

I help with a youth camp every year. Assigning attendees to bedrooms is a massive task - there are 92 bedrooms and the event runs for a week, with attendees staying for varying lengths of time, and beds needing to be reused.

It currently takes a volunteer ~a week to assign people to rooms. There are lots of rules to follow, and as not all attendees stay for the full week assignment is done on a night by night basis.

I want to automate the task. The programming language and computational cost are implementation details, and I can format the input data/rules however needed (inc code generation). Anything that saves hours of tedium...

Available techniques

I have no domain expertise, so first I have to understand possible approaches.

Constraint programming seemed the obvious approach as there are rules to follow. However the rules aren't binary, and a previous thread introduced me to soft constraints and cost functions.

When I read up on cost functions it pointed me to machine learning and neural networks. These are popular but I believe need sets of data to train them, which is something I don't have - I could create, but that'd take more time overall than doing assignment manually. And I know the constraints already: I don't have to deduce them from data.

Q: Is a cost function in Prolog different to in machine learning?
Q: Is machine learning a 'fit' for this problem?
Q: Are there other approaches I've overlooked?

I can't find room assignment problems being discussed on the web, in journals etc; It must be common so I am missing some domain-specific terminology. With hospitals and hotels needing it, I'm sure it is well researched.

Q: What is a bed-assignment problem called in the literature?

Time-based assignments

I also have a conceptual problem. I can see how I solve for one night, but how do I think of modelling multiple nights?

The constraint solver (or other technique) is unaware of time (and won't know 2016-09-05 comes before 2016-09-06), but I need to input the nights people stay and see the assignments per-night.

Q: How should I consider time series?

Conceptually grasping the output

The second is: How would the system output which bedrooms people are assigned to? In a Prolog sudoku solver (for example) there can be multiple solutions, but that's with hard constraints. With fuzzy constraints, would I end up with a probability that person X is in Room Y, and a probability they're also in Room Z (a quantum superposition if you like)?

Q: What will the output be like?

Partial solutions are OK

A first-pass assignment which has to be manually adjusted would save time. As would manually assigning the 'complicated' attendees (like night security, who sleep in a particular room) and letting the computer do the rest.

Q: Does this make the problem easier to solve?

My attempt

Originally I thought of resurrecting my one-semester of Prolog knowledge from 13 years ago, and setting constraints for all criteria. This worked for a very simple cases, but I failed once I moved beyond "must" criteria to grey-rules and compromises.

Sample Rules (constraints)

All rules have different priorities. To simplify I've grouped by must, should and nice.

must Same gender in room
- Unless over-ridden by "Must share with" option e.g. couples
must People who need disabled-friendly rooms get them
must If the attendee needs a room with a cot for their baby, they must get it
must Attendees who specify "Must Share with X" or "Must Share with Y & Z" must be assigned the same room
- They may not be staying for the same number of nights (e.g. A stays for Mon-Thu, B for Tue-Fri). Blocking out beds for the entire period is OK)
- the "Must Share With" relationship can be unidirectional or bidirectional - I can implement either
must/should If an attendee needs a single room, they must get it unless there's no possible solution
should Group attendees in rooms by roles, e.g. "Youth", "Youth leaders", "Cooks", "Leaders". Some roles are more suitable to mix than others.
should Minimise room-hopping: once you have a bed, stay in it for all nights. Unless there's no possible solution
should Couples are prioritised rooms with double beds
- (I haven't figured out how to make a rule for this, which doesn't assume all "Must Share With" relations are couples. At the moment it's done with human knowledge)
nice Group attendees in rooms by university they attend (where applicable)
nice Prioritise rooms with en-suite facilities to non-youth roles

There are more rules (e.g people with dietary requirements must stay in a particular building) but this provides enough examples.

The venue charges per-bed not per-room, so minimising the number of rooms used is NOT important - this year at least.

Similar assignment has to be done for attendees to dining rooms & washing-up rotas, but both are much simpler.

Sample data set

rooms:
    room1:
        building: Building1
        capacity: 2
        is_ensuite: yes
        has_cot: yes
    room2:
        building: Building2
        capacity: 4
        is_ensuite: no
        has_cot: yes
    room3:
        building: Building1
        capacity: 2
        is_ensuite: no
        has_cot: yes
    room4:
        building: Building1
        capacity: 4
        is_ensuite: no
        has_cot: no
    room5:
        building: Building1
        capacity: 4
        is_ensuite: no
        has_cot: no
---
people:
    albert:
        must_share_with: @brenda
        needs_cot: yes
        role: leader
        gender: m
        arrive: 2016-09-05
        depart: 2016-09-10
    brenda:
        role: no role
        gender: f
        arrive: 2016-09-06
        depart: 2016-09-09
    steve:
        role: student
        university: Cambridge
        gender: m
        arrive: 2016-09-07
        depart: 2016-09-09
    jason:
        role: student
        university: Bristol
        gender: m
        arrive: 2016-09-07
        depart: 2016-09-09
    brian:
        role: tech
        gender: m
        arrive: 2016-09-05
        depart: 2016-09-10
    clare:
        role: speaker
        gender: f
        arrive: 2016-09-08
        depart: 2016-09-09
    george:
        role: band/after hours
        gender: m
        arrive: 2016-09-07
        depart: 2016-09-08
    sarah:
        role: band/after hours
        gender: f
        arrive: 2016-09-07
        depart: 2016-09-08
    john:
        role: band/after hours
        gender: m
        arrive: 2016-09-08
        depart: 2016-09-09
    janet:
        role: band/after hours
        gender: f
        arrive: 2016-09-08
        depart: 2016-09-09

Sample outcomes

| Room  | Capacity | 2016-09-05 | 2016-09-06     | 2016-09-07     | 2016-09-08     | 2016-09-09     | 2016-09-10 | 
|-------|----------|------------|----------------|----------------|----------------|----------------|------------| 
| room1 | 2        | albert     | albert, brenda | albert, brenda | albert, brenda | albert, brenda | albert     | 
| room2 | 4        |            |                | jason, steve   | jason, steve   | jason, steve   |            | 
| room3 | 2        | brian      | brian          | brian          | brian          | brian          | brian      | 
| room4 | 4        |            |                | george         | john           |                |            | 
| room5 | 4        |            |                | sarah          | janet          |                |            |

Or (whether this is acceptable depends which roles can share rooms, e.g. band members go to bed at 3am, tech gets up at 6am):

| Room  | Capacity | 2016-09-05 | 2016-09-06     | 2016-09-07     | 2016-09-08     | 2016-09-09     | 2016-09-10 | 
|-------|----------|------------|----------------|----------------|----------------|----------------|------------| 
| room1 | 2        | albert     | albert, brenda | albert, brenda | albert, brenda | albert, brenda | albert     | 
| room2 | 4        |            |                | jason, steve   | jason, steve   | jason, steve   |            | 
| room3 | 2        | brian      | brian          | brian, george  | brian, john    | brian          | brian      | 
| room4 | 4        |            |                | sarah          | janet          |                |            | 
| room5 | 4        |            |                |                |                |                |            |