[gecode-users] Taking an n-ary OR of distinct constraints?

[Jay]

Hi,

I am building a model incrementally. I know in advance how many 
variables there will be, but the constraints will be added to the model 
through a graph search. I will have n integer variables, each taking a 
value from an integer domain {1,...,k}. During the graph search, we are 
given a sets of alldifferent (i.e. distinct) constraints. In a set of 
alldiff constraints, at least one has to be satisfied (but not 
necessarily all!).

For example, a constraint to the model could be: (alldifferent(x1,x2,x3) 
OR alldifferent(x2,x4,x6) OR alldifferent(x1,x2,x8)), where x_i's are 
variables. If this 3-ary OR of 3 alldiff constraints is denoted by X, 
the ultimate model could be say: (X AND Y AND Z), where Y and Z are 
similar sets of alldiffs.

As far as I could tell from the documentation, an n-ary OR is not 
supported between constraints. I can do this easily in MiniZinc though 
(just use \/), so I wonder if I am mistaken here. If that is the case, 
what is a convenient way of modeling such an n-ary OR between 
alldifferent constraints?