Bug? Backsampling with Noisy Relevance crashing

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jonnie
Posts: 41
Joined: Mon Feb 06, 2012 12:49 pm

Bug? Backsampling with Noisy Relevance crashing

Post by jonnie »

Hello,
I recently discovered the possibility to activate/deactivate relevance reasoning in SMILE and promptly stumbled over some crashes.
It happened with other algorithms as well (eg EpisSampling) but one case that I have isolated is using Backsampling with noisy relevance reasoning enabled (EnableNoisyMAXRelevance). The application crashes when calling UpdateBeliefs. If I use Lauritzen, or don't enable noisy relevance, the inference runs fine.
I should say the model has a lot of noisyMAX nodes.
I also was able to reproduce the crash in GeNIe (setting DSL_NOISYMAXRELEVANCE=1 in the network's user properties). I press the lightning button and after a second Windows tells me that GeNIe 2.0 has stopped working.
Why does that happen? Is it a bug?
Regards & thanks in advance :)
shooltz[BayesFusion]
Site Admin
Posts: 1417
Joined: Mon Nov 26, 2007 5:51 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by shooltz[BayesFusion] »

Is it a bug?
It's definitely a bug. Can you post your network here so we can reproduce it locally?
jonnie
Posts: 41
Joined: Mon Feb 06, 2012 12:49 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by jonnie »

I'll see if the error occurs on an obfuscated model as well, and PM you about it.
Thanks for taking care of this :)
jonnie
Posts: 41
Joined: Mon Feb 06, 2012 12:49 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by jonnie »

Update: The crash is a segfault because of a NULL pointer dereference. The bug lies in 15yo legacy code and is therefore not probable to be fixed soon.
Workaround: don't use this combination :)
orzech
Posts: 51
Joined: Wed Aug 04, 2010 11:40 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by orzech »

Thanks for the update!
jonnie
Posts: 41
Joined: Mon Feb 06, 2012 12:49 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by jonnie »

Update: after conducting experiments, I found that the bug occurs:
  • in ALL approximate algorithms, plus in LauritzenOld,
  • when noisy relevance is enabled, and the model contains noisy nodes,
  • only when evidence is set.
(Though I don't know if the latter is valid in general or only in my cases.)
shooltz[BayesFusion]
Site Admin
Posts: 1417
Joined: Mon Nov 26, 2007 5:51 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by shooltz[BayesFusion] »

I can confirm the crash in four approximate algorithms and old Lauritzen implementation. However, AIS and EPIS return DSL_NO_USEFUL_SAMPLES (-5).
jonnie
Posts: 41
Joined: Mon Feb 06, 2012 12:49 pm

Re: Bug? Backsampling with Noisy Relevance crashing

Post by jonnie »

Oh, you're correct. I tested with a slightly different model; I'll PM that to you.
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