Opened 10 years ago

Closed 10 years ago

#12558 closed defect (fixed)

Numerical noise in hmm.pyx

Reported by: vbraun Owned by: mvngu
Priority: blocker Milestone: sage-5.0
Component: doctest coverage Keywords: hidden markov model
Cc: mhampton, jdemeyer Merged in: sage-5.0.beta6
Authors: Volker Braun Reviewers: Jeroen Demeyer
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Status badges

Description

I found some more numerical noise in this doctest in the hidden markov model stuff:

File "/home/vbraun/tesla/sage-5.0.beta4/devel/sage/sage/stats/hmm/hmm.pyx", line 281:
    sage: m
Expected:
    Discrete Hidden Markov Model with 2 States and 2 Emissions
    Transition matrix:
    [1.0134345614...e-70               1.0]
    [              1.0 3.99743527136e-19]
    Emission matrix:
    [7.3802215662...e-54               1.0]
    [              1.0  3.9974352626e-19]
    Initial probabilities: [0.0000, 1.0000]
Got:
    Discrete Hidden Markov Model with 2 States and 2 Emissions
    Transition matrix:
    [1.01343456147e-70               1.0]
    [              1.0 3.99743527135e-19]
    Emission matrix:
    [7.38022156625e-54               1.0]
    [              1.0  3.9974352626e-19]
    Initial probabilities: [0.0000, 1.0000]

Attachments (1)

trac_12558_numerical_noise_in_hmm.patch (897 bytes) - added by vbraun 10 years ago.
Initial patch

Download all attachments as: .zip

Change History (7)

Changed 10 years ago by vbraun

Initial patch

comment:1 Changed 10 years ago by vbraun

  • Authors set to Volker Braun
  • Cc mhampton jdemeyer added
  • Priority changed from major to blocker
  • Status changed from new to needs_review

comment:2 Changed 10 years ago by jdemeyer

  • Reviewers set to Jeroen Demeyer
  • Status changed from needs_review to positive_review

Could you state on which system this happens? The patch obviously looks good.

comment:3 follow-up: Changed 10 years ago by vbraun

This is on a i7-920, 12GB ram, Tesla GPGPU card (of course not used in the doctest), running Ubuntu 11.10 i386(!). Taking the less beaten path with a 32-bit OS (don't ask).

comment:4 in reply to: ↑ 3 Changed 10 years ago by jdemeyer

Replying to vbraun:

Tesla GPGPU card (of course not used in the doctest)

would be über-cool though...

running Ubuntu 11.10 i386(!). Taking the less beaten path with a 32-bit OS (don't ask).

Interesting that I haven't seen this failure on Skynet cicero (Fedora 15 i386, Pentium 4).

comment:5 Changed 10 years ago by vbraun

Cicero is running Fedora 16, for the record.

The i7 has more SSE ops, if the compiler used those instead of FPU then that would easily explain the slightly different precision. GCC on tesla is 4.6.1.

comment:6 Changed 10 years ago by jdemeyer

  • Merged in set to sage-5.0.beta6
  • Resolution set to fixed
  • Status changed from positive_review to closed
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