[gecode-users] Gecode 4.0.0

Fri Nov 4 14:55:21 CET 2011

Hi,

As Christian said, I am interested in having FloatVar in Gecode. I  
contacted him last Spring and started work during Summer.
I try to follow Gecode standards as close as possible. All interval'  
stuff are based on boost intervals.
Up to now, I designed FloatVar and views (FloatView, MinusView and  
OffSetView) and a bunch of propagators :
- Linear (Lg, Gq, Eq)
- Arithmetic (Square, Sqrt, Abs, Pow, NthRoot, Mult, Div, Min, Max)
- Trigonometric (Sin, Cos, Tan, ASin, ACos, ATan)
- Transcendental (Exp, Log)
- Channel (to int)

For a first release it may be enough, so I concentrate on tests to  
remove bugs. I plan to add tools for modeling (like other Gecode  
Variables and constraints), but I must first solve an issue about the  
rounding for trigonometric and transcendental functions. Indeed, boost  
doesn't provide full rounding functions for trigonometric and  
transcendental functions. To achieve correct rounding, it relies on  
other libraries like MPFR. If I can't rely on standard C maths  
functions to get a correct rounding, I have to investigate on other  
alternatives. MPFR is not a good choice for Windows users, so maybe  
another library (CRLibm ? others ?). I'd appreciate any advice on  
this. Does someone known a good "light" maths library which gives  
exact rounding ?

If you have any questions or remarks, don't hesitate to contact me!

Cheers,
Vincent

Christian Schulte <cschulte at kth.se> a écrit :

> Hi Filip,
>
> I started some time ago to look into the FloatVar stuff but then I got
> contacted by Vincent Barichard about that. Vincent expressed his interest
> and has already arrived at a second prototype. I am quite positive that this
> will lead to a good module for 4.*.
>
> Vincent, maybe you can describe the status so far.
>
> Best
> Christian
>
>
> --
> Christian Schulte, www.ict.kth.se/~cschulte/
>
>
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> Of Filip Konvicka
> Sent: Thursday, November 03, 2011 7:11 PM
> To: users at gecode.org
> Subject: Re: [gecode-users] Gecode 4.0.0
>
> Christian,
>
> Sorry to reply so late...
>
> The list of features sounds great, especially the symmetry breaking (though
> I admit that I haven't looked at the propagator groups yet).
>
> Gonzalo from the AVISPA team contacted me in May regarding the Float Vars
> work they were doing, but I haven't heard from them since.  Do you have any
> information on this? Are you counting on using their implementation? Or do
> you plan to do this yourself?
>
> Thanks,
> Filip
>
>> Damn it, there are two pieces of information missing...
>>
>> Timeline: we aim at the second quarter of 2012 for Gecode 4.0.0. But
>> today I went through some older emails (written when we discussed what
>> Gecode 3.* should be) and there I wrote that Gecode 4 should be around end
> of 2009.
>> Okay, still trust me! This time everything is much different ;-) Just
>> kidding.
>>
>> Then, of course: Is there something that we absolutely must do for our
>> users?
>>
>> Christian
>>
>> --
>> Christian Schulte, www.ict.kth.se/~cschulte/
>>
>>
>> -----Original Message-----
>> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On
>> Behalf Of Christian Schulte
>> Sent: Friday, October 14, 2011 3:03 PM
>> To: users at gecode.org
>> Subject: [gecode-users] Gecode 4.0.0
>>
>> Dear all,
>>
>> As this year has already a number of releases of Gecode from the 3.*
>> version series we have decided to slow the pace and prepare for Gecode
>> 4.0.0 as the next major release.
>>
>> This mail is just to assure you that we are not dormant but that it
>> will take longer before the next version appears. If there is the need
>> for a bug fix release we will of course do that in the meantime.
>>
>> Our current plan is to include the following features:
>>
>> - Integrate propagator groups, see here:
>>
>> http://web.it.kth.se/~cschulte/paper.php?id=LagerkvistSchulte:CP:2009
>>
>> - Integrate lightweight dynamic symmetry breaking, see here:
>> 	Lightweight Dynamic Symmetry Breaking.  C. Mears, M. Garcia de la
>> Banda, B. Demoen, M. Wallace.
>>       SymCon'08.
>>     LDSB is a dynamic symmetry breaking method designed to handle
>>     common symmetries efficiently under any variable and value
>>     ordering.
>>
>> - Integrate float variables
>>
>> - Provide modeling layer for float variables
>>
>> - Support for restarts during search and large neighborhood search
>>
>> - Make randomized tie-breaking more flexible
>>
>> - Modeling layer for scheduling constraints
>>
>> - Branching for scheduling problems
>>
>>
>> Some more speculative things that might or might not make it are:
>>
>> - Integrate discrepancy-based search that is not LDS (?)
>>
>> - Half-reification, see here:
>> 	Thibaut Feydy, Zoltan Somogyi, Peter J. Stuckey: Half Reification
> and
>> Flattening. CP 2011: 286-301
>>
>> - Redundancy analysis, see here:
>> 	http://web.it.kth.se/~cschulte/paper.php?id=SchulteStuckey:PPDP:2008
>>
>> Best
>> Christian
>>
>> --
>> Christian Schulte, www.ict.kth.se/~cschulte/
>>
>>
>>
>>
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>
>
>
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-- 
Vincent Barichard        Université d'Angers (LERIA)
Tel: 02 41 73 52 06      Département Informatique
Fax: 02 41 73 50 73      H203