I did notice an enormous amount of propagations. is there some way I can detect slow convergency? or is there something I can do about it?
I'll try to make the model simpler. see if I can reproduce the problem with a limited model. thanks, Kurt Van Den Branden | Agfa Graphics From: Vincent Barichard <[email protected]> To: "[email protected]" <[email protected]> Cc: Kurt Van Den Branden/AMAUK/AGFA@AGFA, Gecode <[email protected]> Date: 15/04/2015 17:05 Subject: Re: [gecode-users] model with float variables sometimes hangs during search Sent by: [email protected] Hi, My first thought is that it is a slow convergency process. It often occurs when linear constraints are involved with particular coefficients. A first clue may be the number of propagations done in one call to Space::status(). For the cases where the search ends (with a big amount of time) you may check the number of propagations done. If it is abnormally huge, it's probably a slow convergence. Without digging in the model and trace the search, I can't say much more. Sorry .... Regards, Vincent 2015-04-15 16:05 GMT+02:00 Christian Schulte <[email protected]>: Hi, This could be a feature and not a bug in that constraint propagation is just very slow to converge. For floating point numbers there is this risk. I would not know what to suggest without knowing how the model looks like but I am also not an expert in floating point. Vincent: do you have an idea? Cheers Christian -- Christian Schulte, www.gecode.org/~schulte Professor of Computer Science, KTH, [email protected] Expert Researcher, SICS, [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Kurt Van Den Branden Sent: Wednesday, April 15, 2015 4:00 PM To: [email protected] Subject: [gecode-users] model with float variables sometimes hangs during search hi, I have a Gecode model that uses float variables. I use a BAB searchengine with a Search::TimeStop object to interrupt the search when it takes too long. I noticed that when the model is created with certain parameters, the search isn't interrupted at the requested timelimit. it either continues a lot longer than allowed, or it doesn't stop at all. in these cases, the debugger shows that it's the method Space::status that doesn't return sometimes. it keeps on propagating and never stops. I haven't been able to reproduce this with a limited test model yet. Does anybody have tips on what could cause this problem? Kind Regards, Kurt Van Den Branden | Agfa Graphics -- Vincent Barichard Université d'Angers (LERIA) Tel: 02 41 73 52 06 Département Informatique Fax: 02 41 73 50 73 H203
_______________________________________________ Gecode users mailing list [email protected] https://www.gecode.org/mailman/listinfo/gecode-users
