Re: Social Golfers

Hi Warwick,

    Once again. Thanks for your help. Yes this works just fine. My 
attempt at C4 was:

    % C4: All pairs of golfers must play each other at most once
    (for(X,1,NumGolfers-1), param(Groups,Weeks,NumGolfers) do
        (for(Y,X+1,NumGolfers), param(X,Groups,Weeks) do
        (for(W,1,Weeks),
         foreach(U,List), param(Y,X,Groups) do
            (Groups[X,W] == Groups[Y,W] ->
            U is 1
            ;
            U is 0
            )
         sum(List) #=< 1
        )
        )
    ).

I did now know to create this constraint correctly.

#=(Groups[X, W], Groups[Y, W], Bool)

Also, I realised that what I really want here is sum(List)  #= 1 since 
I'm interested in maximum socialization.

I'm not clear on how the sorted constraint you suggested, instead of G 
occurrence constraints on each Groups column, can enforce
Group size?

Thanks,
Mark.