[gecode-users] Clockwise constraint

[Guido Tack]

Malcolm Ryan wrote:

> On 02/06/2008, at 5:18 PM, Guido Tack wrote:
>>
>> Oh, I somehow didn't see that it's always ternary!  In that case you
>> might really want to try the extensional constraint.  Just implement
>> a generator that lists all allowed tuples.
>
> Nice idea, but really not viable. In practice the domains are much
> larger than 4 (more like 100), and the table size would be O(n^3).

We just tried it (just for fun ;-), and for domain size 100 it's just  
under 500 000 tuples (which takes about 10M of memory).  For domain  
size 200 it's around 4 000 000 tuples, which is still manageable with  
under 100M of memory.  Generation takes less than a second.

Even if you use more than one of these propagators, you can reuse the  
same table for each one.  So, you might actually want to try this, it  
may work!

Cheers,
	Guido