[gecode-users] Dynamic Branching Support?

[Christian Schulte]

Uuups, I would have no idea how to wrap these branchers inside branchers. And honestly, that does not sound like a really good deal. It might be much easier to do your own branchers that store more than one array of views. So, no hint here ;-)

I think you have to read again about AFC and play a little with it... Try it!

Cheers
Christian

--
Christian Schulte, www.gecode.org/~schulte
Professor of Computer Science, KTH, cschulte at kth.se
Expert Researcher, SICS, cschulte at sics.se


-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf Of Matthias Goldhoorn
Sent: Tuesday, April 14, 2015 8:30 AM
To: cschulte at kth.se; users at gecode.org
Subject: Re: [gecode-users] Dynamic Branching Support?

Good morning and thanks for your Answer first,

I already read the Section B, my problem is that i still want to use the variable-based branchers within my own brancher.
My question therefore is how can i add a local instance of a brancher in my self-written brancher?
As i understood i cannot call branch(...) inside my own brancher. 
Because this would register the brancher on the Space.
I need a way to instanciate the brancher and then call the 'child' 
brancher in choice/commit/(status) function from my brancher.
Can you give me a hint howto create a brancher for this?

I tried to change the brancher for my space, but unfortunately the
brancher(id) function are pure private to space. Therefore it seems to forbidden to do this on the space directly.

Regarding AFC, as i understood it does not change the layout of the search tree (which on the other hand would be the case if i write a own brancher). It only searches for another node to continue the search. I Still want all solution for my 'problem'. Therefore AFC might (from my
understanding) not the way to go?

Best,
Matthias

On 13.04.2015 21:32, Christian Schulte wrote:
> Hi Matthias,
>
> Well there is a very simple answer which might be not very satisfying, though: the variable-value based branchings are just some pre-defined abstractions that come with Gecode. In principle you can implement whatever you like, the entire Part B of MPG is devoted to this.
>
> I do not know how much you have been exploring with the pre-defined variable selection strategies. But maybe you want to try ideas such as AFC and using restarts for search first. They sometimes can be remarkably effective.
>
> Cheers
> Christian
>
> --
> Christian Schulte, www.gecode.org/~schulte Professor of Computer 
> Science, KTH, cschulte at kth.se Expert Researcher, SICS, 
> cschulte at sics.se
>
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On 
> Behalf Of Matthias Goldhoorn
> Sent: Monday, April 13, 2015 04:04 PM
> To: users at gecode.org
> Subject: [gecode-users] Dynamic Branching Support?
>
> Hi to everyone on the ML,
> i'm new to gecode and have already a kind of bug problem .
>
> My Search will not Terminate within days. I have several SetVarArrays, BoolArrays and so on on my Space.
> The Solutions they are found are valid for me, but the search is simply to slow (and sometimes to memory exhaustive).
> I used already gist for introspection, my problem is that i first branch on a BoolVarArrays which reduces the search space quite well until a spefici point. At this point i would like to keep Post prune the BoolVarArray and Continue branching on a SetVarArray. This wold faster reduce my search space than continue the branching on the Bool one.
>
> My question therefore is: is there a way to select dynamically the branching set?. I found on the documentation that it is possible to select a variable INSIDE a structure for branching. But that i need is a dynamic selection of the Set/Array where the branching should be done.
> Is this possible in gecode. Or (@dev's) is the extension possible?
>
> Best,
> Matthias
>
> (P.S. Since i do open-source development i could provide my 
> application if this helps the understanding.)
>
> --
>    Dipl.-Inf. Matthias Goldhoorn
>    Space and Underwater Robotic
>
>    Universität Bremen
>    FB 3 - Mathematik und Informatik
>    AG Robotik
>    Robert-Hooke-Straße 5
>    28359 Bremen, Germany
>
>    Tel.:     +49 421 178 45-4193
>    Zentrale: +49 421 178 45-6550
>    Fax:      +49 421 178 45-4150
>    E-Mail:   matthias.goldhoorn at uni-bremen.de
>
>    Weitere Informationen: http://www.informatik.uni-bremen.de/robotik
>
>
> _______________________________________________
> Gecode users mailing list
> users at gecode.org
> https://www.gecode.org/mailman/listinfo/gecode-users
>


--
  Dipl.-Inf. Matthias Goldhoorn
  Space and Underwater Robotic

  Universität Bremen
  FB 3 - Mathematik und Informatik
  AG Robotik
  Robert-Hooke-Straße 5
  28359 Bremen, Germany

  Tel.:     +49 421 178 45-4193
  Zentrale: +49 421 178 45-6550
  Fax:      +49 421 178 45-4150
  E-Mail:   matthias.goldhoorn at uni-bremen.de

  Weitere Informationen: http://www.informatik.uni-bremen.de/robotik


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