Thanks for the info.
The simplest version would be as before by reification: for each array index i
but the last one, post:
rel(*this, (x[i] == 10) >> (x[i+1] == 11));
If that turns out to be not efficient enough (most likely that is the case if
you have arrays with 20000 elements), then you could implement a simple
propagator. This is described in Part P of MPG. You want to make the propagator
incremental by reading about Advisors in that part.
However, first I would make really sure that your model is correct before
indulging in an implementation exercise.
Cheers
Christian
--
Christian Schulte, Professor of Computer Science, KTH, www.ict.kth.se/~cschulte/
From: Richard Portelli [mailto:richard.port...@gmail.com]
Sent: Tuesday, June 10, 2014 11:11 PM
To: cschu...@kth.se
Subject: Re: [gecode-users] Cleaner way for if/then constraint condition
Hello Christian,
Thank you for your quick answer.
The maximum number of numbers I could have in my array would be around 20 000.
I, for example, know that there will be some numbers of these array (determined
by gecode) that will be equal to a certain value(known before gecode
generation). Lets say 10. I don't know where these numbers with value 10 will
be. However, I know that the numbers just after these number with 10 values
should have the value 10+1.
I hope my explanations are clear enough :)
I really appreciate your help.
Cheers,
Richard
2014-06-10 22:25 GMT+02:00 Christian Schulte <cschu...@kth.se>:
Hi,
This depends very much on whether you want to express your condition:
- For each and every element in the array, or
- Just for a particular element at a certain position in the array
which is statically known, or
- Just for a particular element where the index is not yet know, or
- How large the array would be in practice, or
- …
Same more info might help.
Best
Christian
--
Christian Schulte, KTH, web.it.kth.se/~cschulte/
From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On Behalf Of
Richard Portelli
Sent: Tuesday, June 10, 2014 08:21 PM
To: users@gecode.org
Subject: [gecode-users] Cleaner way for if/then constraint condition
Hello,
I am looking for the "best" way to implement if/then type of constraint
propagation.
An example would be : I have an array of 10 integers with sum =100. If one
element is equal to 10, the following one should be 11.
Adding a lot of these constraint is it ressource intensive or not necessary?
Thanks for your help,
Cheers,
Richard
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