Re: [eclipse-clp-users] negate constraints

Dear all,

thanks to all your help and advices I successfully set up my user defined
reified constraints which no behave as I expect. The Constraint Library
Manual however left some unanswered questions.
On page 22 the manual says:
- Enforcing constraints: It seems to be better to unify the truth reified
values to variables to get active constraints. Is this correct? What are
advantages and disadvantages of passive and active constraints?
- "In the event that the reified variable becomes bound to 0 then the
constraint should actively propagate its negation." How is this active
propagation ensured by my constraints? What do I have to regard?
- same for "actively propagate its normal semantics"

Best regards,
Oliver.


On 1 April 2010 14:29, Alexandre Saidi <Alexandre.Saidi_at_...37...> wrote:

> Dear Oliver,
> (back to my office) ..
> Your sentence may have 2 meanings :
> 1- any var (One or more) greater than 8 then at least one less than 8
> 2- one per one (if one var greater than 8 then one smaller than 8)
>
>
> In the  case-1, take just what I sent but change the ‘OR’ to an ‘AND’   as
> follows :
> :- lib(fd).
> example  :-
>     OutputModel = [A, B, C, D],
>     A #:: 1..10,
>     B #:: 1..10,
>     C #:: 1..10,
>     D #:: 1..10,
>
> % NOT ALL  can have value greater or equal to 8 (i.e. A <8 or B<8 or C<8 or
> D<8)
>    #\+ (A #>= 8 #/\ B#>= 8  #/\  C #>= 2 #/\ D#>= 2),  % NOT ALL can have
> value>8
>   labeling(OutputModel),
> writeln(OutputModel).
>
> N.B. : this means that you must always have one of the vars [A,B,C,D] less
> that 8. So we can also have the following solution (just change the
> constraint line) :
> …
> A #< 8 #\/ B#< 8 #\/  C #< 8 #\/ D#< 8,
> ...
>
> OR :
>
> lib(fd). lib(ic_global).
> % the constraint part (the rest dose not change) :
> V #:: 1..10, N#:: 0..4, occurrences(V,[A,B,C,D],N), V #< 8, N #>=1,
> ….
>
>
> For the case-2 : "if one has a value greater, then one must have a value
> less than 8,   if 2 have values  > 8 then 2 must have value less than 8 (no
> more case) : you can change the last solution to that case.
>
>
> Alex.
>
> Le 31 mars 2010 à 14:27, Oliver Shycle a écrit :
>
> if any variable has a value greater than eight, there must be at least one
> variable with a value smaller than eight."
>
>
>  -------------------------------
> Alexandre Saidi
> Maitre de Conférences
> Ecole Centrale de Lyon-Dép. MI
> LIRIS-CNRS UMR 5205
> Tél : 0472186530, Fax : 0472186443
>
>
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>