[gecode-users] Retrieval of status and elimination of the SS_BRANCH case

[Guido Tack]

Hi.

> I am using the status method to get the status of my space. In case the
> status returns SS_BRANCH I would like to branch the search tree and find
> out if the status is SS_SOLVED or SS_FAILED. In other words I want to
> eliminate the case where the status returns SS_BRANCH [only solved or
> failed spaces are accepted]. I am doing something like:
>
> QSpace* qs=new QSpace;   //this is a subclass of Space where my problem is
> defined
>   qs->getStatus();                //this is where I print the status of my
> space. In my case this returns SS_BRANCH
>   DFS<QSpace> e(qs,25,200);  //this is where I am using the Depth First
> Engine to search through the tree
>   qs->getStatus();                //this is where I would expect to see
> either SS_SOLVED or SS_FAILED but not SS_BRANCH
>
> The problem is that after the second retrieval of the status I get again
> SS_BRANCH. What am I doing wrong?

You only construct the search engine, but don't actually perform any search. 
To do that, call e.next(). It either returns you a new QSpace that is a 
solution, or NULL if there was no solution. Note that, as Gecode's search is 
based on copying, the search engine really returns a copy of your original 
space.

Cheers,
	Guido

-- 
Guido Tack
Programming Systems Lab, Saarland University, Germany
http://www.ps.uni-sb.de/~tack