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alldifferent(+Vars)

All members of Vars are different
Vars
A collection (a la collection_to_list/2) of variables or integers

Description

Constrains all elements of a collection to be pairwise different (and integral). This is an implementation with the same semantics as the standard alldifferent/1 constraint, but with stronger propagation behaviour. It checks for exhaustion of all sub-ranges of possible values.

Any input variables which do not already have finite bounds will be given default bounds of -10000000 to 10000000.

Examples

    ?- length(Xs,5), Xs::1..4, alldifferent(Xs).
    no (more) solution.


    ?- [X1,X2]::1..2, [X3,X4,X5]::1..5, alldifferent([X1,X2,X3,X4,X5]).

    X1 = X1{[1, 2]}
    X2 = X2{[1, 2]}
    X3 = X3{[3..5]}
    X4 = X4{[3..5]}
    X5 = X5{[3..5]}

    Delayed goals:
        alldifferent([X1{[1, 2]}, X2{[1, 2]}], 1)
        alldifferent([X3{[3..5]}, X4{[3..5]}, X5{[3..5]}], 1)
    

See Also

ic_symbolic : alldifferent / 1, ic_global : alldifferent / 1, fd : alldifferent / 1, ic : alldifferent / 1, sd : alldifferent / 1, alldifferent / 2, lists : collection_to_list / 2