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From: Oliver Shycle <oliver.shycle_at_...1...>

Date: Wed, 31 Mar 2010 14:27:35 +0200

Date: Wed, 31 Mar 2010 14:27:35 +0200

Hello, well I think the negation axample was not really good to express what i want. Let me formulate the problem like this: We stick to the variables and their domains as before. I need constraints that express the following: "if any variable has a value greater than eight, there must be at least one variable with a value smaller than eight." ------------------------------- example :- OutputModel = [A, B, C, D], A #:: 1..100, B #:: 1..100, C #:: 1..100, D #:: 1..100, % constraints labeling(OutputModel), writeln(OutputModel). --------------------------------- I dont know how to express such kind of constraints. Thanks for your help. Oliver. On 31 March 2010 11:02, Alexandre Saidi <Alexandre.Saidi_at_...37...> wrote: > Hi Olivier, > I’m not sur i understand what you want to do with the negation. > > Tell me what if : > example :- > > OutputModel = [A, B, C, D], > A #:: 1..100, > B #:: 1..100, > C #:: 1..100, > D #:: 1..100, > > #\+ (A #> 8 #\/ B#> 8 #\/ C #> 8 #\/ D#> 8), > > labeling(OutputModel), > writeln(OutputModel). > > In both cases, constraint propagation will restrict variable domaine. > It’s better not to use Disjunction (like member). > > Alex > > Le 30 mars 2010 à 09:57, Oliver Shycle a écrit : > > Hi all, > > I have a problem to express negated constraints in ECLiPSe. In my programm, > I want to express what value certain interval constraints may NOT have. > Consider the following problem description: the program shall find values > for four variables such that the values are NOT greater than 8. > > Here's the code: > ------------------------------------------------------ > :- lib(ic). > > example :- > > OutputModel = [A, B, C, D], > A #:: 1..100, > B #:: 1..100, > C #:: 1..100, > D #:: 1..100, > > not(wrong_value(OutputModel)), > labeling(OutputModel), > writeln(OutputModel). > > wrong_value(Vars) :- > member(Var, Vars), > greater_eight(Var). > > greater_eight(X) :- > X #> 8. > ------------------------------------------------------ > > I know that I rather could limit the variable's domains to a maximum of 8, > but I want to demonstrate my problem with this snippet. When ECLiPSe comes > along the constraint "X #> 8" with the first variable of the list, the term > evaluates to true. Therefore wrong_value evaluates to true without even > setting up constraints for the other variables. The negation > not(wrong_value(OutputModel)) thus becomes false and ECLiPSe sais it can't > find a solution. If I test the code with a set of integers instead of > variables everything works as expected. > How can I tell ECLiPSe not to evaluate X #> 8 instantly, but keeping the > constraint in mind for later instantiation during labeling/1? > > Many thanks for your help. > > Oliver. > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > > http://p.sf.net/sfu/intel-sw-dev_______________________________________________ > ECLiPSe-CLP-Users mailing list > ECLiPSe-CLP-Users_at_lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/eclipse-clp-users > > > ------------------------------- > Alexandre Saidi > Maitre de Conférences > Ecole Centrale de Lyon-Dép. MI > LIRIS-CNRS UMR 5205 > Tél : 0472186530, Fax : 0472186443 > > > > > > >Received on Wed Mar 31 2010 - 12:27:42 CEST

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