Right now I have a single choice predicate that defines my search space.
#const nRounds = 3.
#const nPlayers = 17.
#const nSeats = nRounds * nPlayers.
#const nRooms = 3.
#const nDecks = 6.
nSeats { seat(1..nPlayers, 1..nRooms, 1..nDecks) } nSeats.
I would like to restrict this search space as I'm starting to run into performance problems. In my set up each each player can only appear in 4 "seat" predicates so I would like something along the lines of:
#for i in 1..nPlayers
nRounds { seat(i, 1..nRooms, 1..nDecks) } nRounds.
#endfor
which would basically turn into something like this internally:
nRounds { seat(1, 1..nRooms, 1..nDecks) } nRounds.
nRounds { seat(2, 1..nRooms, 1..nDecks) } nRounds.
nRounds { seat(3, 1..nRooms, 1..nDecks) } nRounds.
...
I could, of course, "spell this out myself" i.e. use another language to generate these lines but I don't see why this wouldn't exist in clingo.
The reason I am looking for a way to do this in the first place is because I expect that (nRooms*nDecks choose nRounds) * nPlayers is going to be much smaller than (nRooms*nDecks*nPlayers) choose nRounds*nPlayers which is in turn much better than {seat(P, R, D)} with its 2^(nRooms*nDecks*nPlayers) which is what I started with.
Even with constraints in my code that restrict the actual possible sets I can end up with so that all three of these representations are equivalent, there are still performance benefits to gain from such manual search space pruning right?
The "for loop" you are looking for is a straight forward rule:
nRounds { seat(S, 1..nRooms, 1..nDecks) } nRounds :- S = 1..nPlayers.
Check the difference to your code with clingo --text
I would also advise you to seperate the seat(P,R,D) predicate into several smaller ones (depending on your problem.
Like each player is assigned a room p2r(P,R) and every room is assigned to a deck r2d(R,D). This way you save a lot of unecessary combinations in your constraints later on. Of course my two predicate may not make sense for your problem but I'm sure you will find a combination to split your seat predicate.