bugGNU Octave - Bugs: bug #41247, failure on calculating expm on...

 
 

bug #41247: failure on calculating expm on complex matrix

Submitter:  None
Submitted:  Thu 16 Jan 2014 09:40:35 AM UTC
   
 
Category:  Libraries Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Segfault, Bus Error, etc.
Status:  Works For Me Assigned to:  None
Originator Name:  Rurounni Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * 3.6.4
Operating System:  * Microsoft Windows Fixed Release:  None
Planned Release:  None
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Mon 20 Jan 2014 12:13:24 AM UTC, comment #13: 

I think the discussion is over, so you are right - the topic can be closed.

Rurounni

Anonymous
Sun 19 Jan 2014 06:49:52 PM UTC, comment #12: 

So it reads to me like this can be closed. Are there any remaining issues to fix here?

Mike Miller <mtmiller>
Group Member
Fri 17 Jan 2014 01:59:26 AM UTC, comment #11: 

Both of Octaves (3.6.4 and 3.8.0) when lunched state that they were configured for i686-pc-mingw32, so I thought it is MinGW version.
Yep, 3.8.0 is fine by me, as far as it works, so I'll stick to it.

Rurounni

Anonymous
Thu 16 Jan 2014 06:13:20 PM UTC, comment #10: 

Ah, I forgot to ask if you have the MinGW or MSVC version of Octave-3.6.4. AFAIK this libblas.dll "bug" is confined to the MinGW versions (with gcc4.6.2 in the name).

Apparently you have the MSVC-version; I'm not sure this bug happens with that version as well.
AFAIU the MSVC and MinGW versions of .dlls aren't interchangeable. (Sorry Jordi I understand this IS a bit hard to follow for non-Windows users :-) )

I wiped a collection of older Octave versions, incl. that 3.6.4-MSVC one, when 3.8.0 came out, so I cannot compare anymore.

If you like Octave-3.8.0 I'd suggest to simply forget 3.6.4.

Philip Nienhuis <philipnienhuis>
Group Member
Thu 16 Jan 2014 05:04:03 PM UTC, comment #9: 

When I change original vc100-libblas.dll in my Octave 3.6.4 to libblas.dll from Octave 3.8.0 (of course I didn't forget to change name) the 3.6.4 just wouldn't start, the error:
gcc_s_dw2-1.dll is missing, try to reinstall the program.
If someone has this vc100-libblas.dll I can check whether changing of it will work or not, meanwhile I can stick to 3.8.0 when needed.
Thank you guys all for the help!

Anonymous
Thu 16 Jan 2014 04:47:07 PM UTC, comment #8: 

They are interchangeable. BLAS is a specification with several different implementations. Can you please backup the suspect BLAS and try the other one?

Jordi GutiƩrrez Hermoso <jordigh>
Group Member
Thu 16 Jan 2014 04:30:10 PM UTC, comment #7: 

In my Octave's bin folder there is only one libblas library: vc100-libblas.dll Version is 0.2.2, which is rather dated according to the internet, but somehow I can't find a place to download a new one (unfortunately neither there are other libblas files to switch it with as you suggested on my Octave folder). So I can't say for sure is it the source of the problem.
I've installed GNU Octave 3.8.0 in a different folder and there is no such bug in it: expm and det are working fine. In this version in the bin folder there is also only one libblas file:
libblas.dll (however size of this one is 300KB versus 12MB of the previous one, so I think these two are definitely not interchangeable as their names suggest)

Rurounni

Anonymous
Thu 16 Jan 2014 04:16:02 PM UTC, comment #6: 

Is there a canonical bug report about wrong BLAS library crashing Octave on Windows that we could redirect this one to? We get variations of this bug report all the time.

Jordi GutiƩrrez Hermoso <jordigh>
Group Member
Thu 16 Jan 2014 03:44:54 PM UTC, comment #5: 

This smells of the notorious libblas.dll problem.

I can't find the older bug reports now, but there are several of them.

In <OCTAVE_HOME>/bin (OCTAVE_HOME is where you installed Octave-3.6.4) you'll find several libblas.dll versions. Rename your original libblas.dll to something else (like e.g., libblas_org.dll), rename the reference libblas....dll to libblas.dll and try again.
Performance may be less but the reference libblas should be stable.

Philip Nienhuis <philipnienhuis>
Group Member
Thu 16 Jan 2014 11:03:09 AM UTC, comment #4: 

Okay, I'll try to figure that out on holidays - out of my capabilities right now, it will take time - I'm still just a newbie in the Octave. So I'll report later about results, thank you for the help!

Rurounni

Anonymous
Thu 16 Jan 2014 10:47:49 AM UTC, comment #3: 

Then, since expm is a .m file, you could try to understand at which point it crashes.

Marco

Marco Caliari <caliari>
Group Member
Thu 16 Jan 2014 10:38:52 AM UTC, comment #2: 

Hi, Marco!
Thank you for the reply.
Both your suggestions working just fine without any crashes.
By the way my Octave is running on Windows 7 (64bit) and configured for i686-pc-mingw32.
If I wouldn't be able resolve it within some time, I'll try to install 3.8.0 and see whether it will help or not.

Rurounni

Anonymous
Thu 16 Jan 2014 09:46:44 AM UTC, comment #1: 

Hi,

I also think it is a problem with your system, in fact it works for me. Probably something wrong with your blas/lapack library. Can you try


A\[1;1]


(the system is singular, but it should not crash)

and


balance(A)


Marco

Marco Caliari <caliari>
Group Member
Thu 16 Jan 2014 09:40:35 AM UTC, original submission:  

Code with the problem:
A=[i i;i i];
expm(A)
panic: Segmentation violation -- stopping myself...
attempting to save variables to `octave-core'...
save to `octave-core' complete
Sorry if it is some obvious issue - I'm new to the Octave, but I've honestly did quite of googling and couldn't find an answer to resolve this issue. Anytime I'm trying to calculate expm or det on complex matrix Octave crashes (however sqrtm is working fine, also no problem with expm and det applied on matrix consisting of real values).
Probably this is the issue with my computer, but can you guys give at least a hint what can I try to do to fix this?
My package list:
general 1.3.2
java 1.2.9
linear-algebra 2.2.0


Anonymous

 

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    Date Changed by Updated Field Previous Value => Replaced by
    2014-01-20 mtmiller Open/ClosedOpen Closed
    2014-01-19 mtmiller CategoryNone Libraries
    2014-01-16 caliari StatusNone Works For Me

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