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Ublas : |
Subject: Re: [ublas] Fwd: boost/numeric/bindings/lapack
From: Julius Ziegler (ziegler_at_[hidden])
Date: 2008-11-13 04:13:20
Andreas Klöckner wrote:
> On Mittwoch 12 November 2008, Thomas Klimpel wrote:
>
>>> I've received the following patch suggestion from Julius Ziegler. What he
>>> points out does look fishy. Since I've never worked with banded matrices
>>> in LAPACK, I hope someone on the list is better equipped to give a
>>> definitive answer.
>>>
>> The fix from Julius Ziegler is correct (according to the documentation of
>> SGBTRF and ublas/banded_matrix), but it doesn't go far enough. It should
>> also change "assert(ku > 0)" into "assert(ku >= 0)", because that is all
>> that is required by SGBTRF.
>>
>
> I've attached a patch. Let me know if it looks ok, and if so, I'll apply it to
> my tree and release a new snapshot. Note that I've also removed the comments
> above the code snippets in question--they don't seem to apply any more. Tell
> me if I'm wrong.
>
> Andreas
>
I believe now that my suggestion is wrong. SGBTRF seems to require kl
extra diagonals allocated within the matrix band, so the code is
correct. ublas::sgbrtf does not give correct results for me, though, I
will try to put together an example an post it here.
Cheers,
Julius