[gecode-users] Gecode 3.5.0 faster than Gecode 3.7.0?

[Christian Schulte]

Okay, you got me red-handed here: before 3.7.0 count was in fact not domain
consistent for the case
	count(x,y,=,z)
where y is a variable. The pruning for y was actually missing (the values
for y can only be the values in x provided z >= 1).

So, a bug fix if you wish ;-)

Cheers
Christian

--
Christian Schulte, KTH, web.it.kth.se/~cschulte/


-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
Of Kish Shen
Sent: Wednesday, September 14, 2011 2:12 PM
To: users at gecode.org
Subject: Re: [gecode-users] Gecode 3.5.0 faster than Gecode 3.7.0?

Hi Christian,

Thanks for your reply!

The documentation for both 3.7.0 and 3.5.0 say that the single value count
constraint achieves domain consistency. I thought you can't really do better
(more pruning) than domain consistency for single constraints, or am I
mistaken?

Cheers,

Kish

On 14/09/2011 09:35, Christian Schulte wrote:
> This is most likely due to the count constraint. In Gecode 3.7.0 it 
> tries to do more pruning and that might cause the slow down (and your 
> examples might not necessarily profit from the additional pruning).
>
> Cheers
> Christian
>
> --
> Christian Schulte, KTH, web.it.kth.se/~cschulte/
>
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On 
> Behalf Of Kish Shen
> Sent: Tuesday, September 13, 2011 6:41 PM
> To: users at gecode.org
> Subject: [gecode-users] Gecode 3.5.0 faster than Gecode 3.7.0?
>
> Hi,
>
> I have just upgrade the ECLiPSe interface to Gecode from Gecode 3.5.0 
> to 3.7.0. As I am currently doing some work on improving the 
> performance of the interface, I have been doing some timings with 
> example programs, and to my surprise, one of the example is running 
> consistently faster with 3.5.0. The run-times are:
>
> 3.5.0:        16.34s
> 3.7.0:        19.99s
>
> The only change between these two is the version of Gecode used (plus 
> the changes in the C++ code needed for the upgrade, i.e. the #include 
> for the graph and scheduling modules).
>
> As the program is written in ECLiPSe, there is no direct record of the 
> actual Gecode API calls made. The problem is the "roster" example from 
> the ECLiPSe website, modified for use with the Gecode interface. This 
> example is solving a simple rostering problem, and there are a lot of 
> relational constraints posted, plus some boolean expressions, all 
> posted via the MiniModel, and there are also some count contraints 
> (occurrences of one value variant). The search is done in ECLiPSe, 
> i.e. not using the search-engines of Gecode.
>
> Is the above information sufficient for even guessing what the slow 
> down might be due to? If not, what additional information might be needed?
>
> Cheers,
>
> Kish
>
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