[Gecode] Propgator copy

[Guido Tack]

Actually, if the tree doesn't change during propagation (that is, if 
it's only created during initialization of the propagator and not 
touched afterwards), shouldn't it rather be handled like a SharedArray 
in e.g. int/element/int.icc?

Christian Schulte wrote:
> The first issue is that of course your propagator is in charge of copying,
> if needed.
> 
> Secondly, consider whether you really want to always copy! Have a look to
> int/distinct/dom.icc. There the propagator also needs a graph only during
> propagation. It maintains this graph as follows: when the propagator is
> created or copied set the graph to empty. If the propagate function is
> invoked, check whether the graph exists. If not, create it. If yes, update
> it accordingly. Upon destruction delete it, if it exists. Make sure that the
> destructor is called! This you have to do by giving a special flag to the
> propagator. Again see the above mentioned example.
> 
> All the best
> Christian 

-- 
Guido Tack
http://www.ps.uni-sb.de/~tack