Re: [eclipse-clp-users] length time of eclipse

From: Marco Gavanelli <marco.gavanelli_at_...17...>
Date: Fri, 13 Aug 2010 09:19:02 +0200
On 12/08/10 16:29, paniz alipour wrote:
> Hi
> I have a university timetabling program,and 20 tuple as input
> when I reuce the number of inputs to 11 it works as fast as posible but when
> it becomes 12 it hangs.

That is what usually happens when dealing with NP-hard problems.

> my search is labeling(Vars)
>
> what shall IDo?

You can do many many things: you can reformulate your problem with a 
better model, add redundant global constraints, switch to another solver 
amongst the many that ECLiPSe features, change your search strategy, 
define new constraints tailored for your problem, ...

Probably, the quickest modification is changing the search strategy.
As a first tep, have a look at predicate search/6 in the manual, it has 
many parameters; you can find which combination is best for your problem.
But if you want to improve further, you have to write your own search 
predicate, tailored for your problem.

Cheers,
Marco

-- 
Marco Gavanelli, Ph.D. in Computer Science
Dept of Engineering
University of Ferrara
Tel/Fax  +39-0532-97-4833
http://www.ing.unife.it/docenti/MarcoGavanelli/
Received on Fri Aug 13 2010 - 07:19:10 CEST

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