Hi,
No, this is not at all feasible as I tried to explain: the view has (and hence the advisor) has no idea that the view is stored in a view array. Think of it as follows: the view might be stored in different arrays by different propagators. So how could the view and hence the advisor know which array we talk about? Cheers Christian -- Christian Schulte, <http://www.gecode.org/~schulte> www.gecode.org/~schulte Professor of Computer Science, KTH, <mailto:cschu...@kth.se> cschu...@kth.se Expert Researcher, SICS, <mailto:cschu...@sics.se> cschu...@sics.se From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On Behalf Of Valentin Lemière Sent: Tuesday, November 10, 2015 05:20 PM To: cschu...@kth.se Cc: users@gecode.org Subject: Re: [gecode-users] Advisor on a ViewArray and index of assigned variable Hi, I see, thanks for your answer. When an Advisor is used on a BoolView it stores the type of assignment in the delta, which can be accessed with BoolView::one and ::zero. But couldn't an Advisor, when applied to a ViewArray, store the index in the delta and then access it with ViewArray::index? With the index I can get the assigned value but not the other way around. It's not the case right now I understand, but do you think this is something feasible? Regards, Valentin _____ De: "Christian Schulte" <cschu...@kth.se <mailto:cschu...@kth.se> > À: "Valentin Lemière" <valentin.lemi...@unicaen.fr <mailto:valentin.lemi...@unicaen.fr> >, users@gecode.org <mailto:users@gecode.org> Envoyé: Lundi 9 Novembre 2015 20:20:51 Objet: RE: [gecode-users] Advisor on a ViewArray and index of assigned variable Hi, An advisor subscribes to a particular variable implementation through a view hence, the only information that is available by default is which advisor is executed and what is the delta. Additional information – such as the position of an advisor in a view array – must be explicitly stored in the advisor, there is no way around it. Cheers Christian -- Christian Schulte, <http://www.gecode.org/~schulte> www.gecode.org/~schulte Professor of Computer Science, KTH, <mailto:cschu...@kth.se> cschu...@kth.se Expert Researcher, SICS, <mailto:cschu...@sics.se> cschu...@sics.se From: users-boun...@gecode.org <mailto:users-boun...@gecode.org> [mailto:users-boun...@gecode.org] On Behalf Of Valentin Lemière Sent: Monday, November 9, 2015 04:56 PM To: users@gecode.org <mailto:users@gecode.org> Subject: [gecode-users] Advisor on a ViewArray and index of assigned variable Hello everyone, I am a PhD. student and I am currently looking at Gecode to see if it'll fit my needs. I need to implement a global constraint on a large number of boolean variables. So I have extended from NaryPropagator with a view of type BoolView. When a variable is assigned, the propagator infers some knowledge and may assign other variable(s). To get the required information, I added an Advisor to each variable, storing its index; so I can get it in the advise method and provide it to the propagator. But this technique is too slow and creates too much advisors. So I tried adding an Advisor directly to the ViewArray; the advise function is correctly called and I can still get whether the variable was assigned a zero or a one with the delta. But I don't get the index information to find the actual assigned variable. I looked for a static method of ViewArray to convert the delta to this information but couldn't find one. Can an Advisor on a ViewArray get the index of the assigned variable? Or is there another way to deal with a large number of variables other than an Advisor per variable? Regards, Valentin
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