[HN Gopher] Gecode is an open source C++ toolkit for developing ...
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       Gecode is an open source C++ toolkit for developing constraint-
       based systems (2019)
        
       Author : gjvc
       Score  : 59 points
       Date   : 2025-07-05 08:43 UTC (14 hours ago)
        
 (HTM) web link (www.gecode.org)
 (TXT) w3m dump (www.gecode.org)
        
       | gjvc wrote:
       | see also https://github.com/Gecode/gecode
        
         | mzl wrote:
         | Note, the release/6.3.0 branch is the current release.
        
       | ur-whale wrote:
       | A short C++ example of gecode in use on their home page would be
       | real nice.
        
         | wavemode wrote:
         | there are examples in the repo:
         | https://github.com/Gecode/gecode/tree/master/examples
        
           | ur-whale wrote:
           | Thanks for pointing those out, I did in fact find them
           | because my interest level was high enough that I went digging
           | in the github repo.
           | 
           | But as I explain above, a key thing for tech. things like
           | this, which are interesting in an of themselves, is to hook
           | the casual passer-by by very quickly showing him/her what it
           | is about.
           | 
           | For this, you want a very short example front and center on
           | your homepage to get people with little time to see what the
           | stuff can actually do.
        
         | mzl wrote:
         | Adding to wavemode, the Sudoku example is a good starting
         | point:
         | https://github.com/Gecode/gecode/blob/master/examples/sudoku...
         | 
         | In the documentation (https://www.gecode.org/doc-
         | latest/MPG.pdf) there are a lot of worked examples as well.
        
           | ur-whale wrote:
           | Yes, I found those.
           | 
           | The point is to make the example front and center on the
           | homepage so as to very quickly show what this is about to the
           | casual passer-by.
        
           | CamperBob2 wrote:
           | for (int i=0; i<nn; i++) {           distinct(*this,
           | m.row(i), opt.ipl());           distinct(*this, m.col(i),
           | opt.ipl());         }
           | 
           | Weird way to use C++, passing *this to everything explicitly,
           | but maybe they have a reason.
        
             | nurettin wrote:
             | Qt does this as well. It is a common way of preserving a
             | parent-child relationship.
        
       | aninteger wrote:
       | For some reason I pictured this software as a system for
       | developing memory or CPU constrained software. Like granting only
       | 1 mb of memory and maybe having functions executed in a certain
       | number of "clock ticks"
        
       | stargrazer wrote:
       | Interesting, but why post it? Nothing seems to have been
       | committed/updated in about 6 years. There are a number of PRs
       | outstanding. Is it still in use?
       | 
       | The forum implies that not much maintenance happened after the
       | passing of the primary contributor, even if there were good
       | intentions.
       | 
       | Are there other constraint solvers which have subsumed this one?
        
         | osivertsson wrote:
         | I did not know Christian Schulte had passed away! That is sad
         | news that reaches me now five years on from his passing.
         | 
         | https://intra.kth.se/en/eecs/nyheter/in-memory-of-christian-...
         | 
         | I met Christian at a conference in Lund back in 2005 as I was
         | doing my master thesis within the constraint programming area.
         | He came across as both very knowledgeable and very kind and
         | caring. RIP Christian.
        
       | nlewycky wrote:
       | Gecode won the minizinc challenges from inception of the
       | challenge in 2008 until 2012, but these days or-tools wins gold
       | every year 2013 to 2024, and in 2024 swept gold in all
       | categories.
       | 
       | Why is gecode interesting? Why use it over or-tools?
       | 
       | https://www.minizinc.org/challenge/
        
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       (page generated 2025-07-05 23:00 UTC)