[gecode-users] Problems using Stop object with search engines

[Kish Shen]

Hi,

I am trying to use a Stop object with my existing search engine code, 
but the program seem to crash when I try to run the code.

The code that set up the search engine is as follows:

Search::TimeStop timeout(500);
o.stop = &timeout;

DFS<GecodeSpace>* sengine = new DFS<GecodeSpace>(solver, o);

later on (but certainly much less than 500ms of the timeout), in a
different C++ procedure (these are called from ECLiPSe, so I first set 
up the search engine, return to ECLiPSe, and then call the C++ procedure 
to do the search), I get the search engine, and call the next() method:

     DFS<GecodeSpace*> sengine;
     < get the sengine >
     *solverp = sengine->next();

as far as I can tell, the program crashes when next() is called above.

The main change from the existing code (which does not crash) is the 
addition of the option when sengine is created, i.e.

instead of new DFS<GecodeSpace>(solver, o); the old code was new 
DFS<GeCodeSpace>(solver);

when I changed the code back to this version without passing o (but 
still with o declared), the code worked as before (i.e. without timing out).

I am using Gecode 3.0.2 on Linux, if that is a factor.

Is this because the Stop Object was destroyed when I returned from the 
procedure that created it? I thought everything is copied in Gecode?

The Stop object is passed via the stop member of search options. Does 
this mean that only one stop object can be passed to the search engine?
Is it possible to set more than one limit (e.g. for both node and time)?

Thanks in advance for any help!

Cheers,

Kish

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