Re: [ublas] Banded matrix storage

Subject: Re: [ublas] Banded matrix storage
From: Rutger ter Borg (rutger_at_[hidden])
Date: 2013-08-01 07:06:23

On 2013-07-31 17:22, Nasos Iliopoulos wrote:
> Gunter,
> I am working on this bug, but based on the test case I am wondering why
> should the expected row-major data layout be:
>
> 0, 0, 11, 12, 0, 21, 22, 23, 31, 32, 33, 34, 42, 43, 44, 45, 53, 54, 55, 0
>
> And not
>
> 0, 12, 23, 34, 45, 11, 22, 33, 44, 55, 21, 32, 43, 54, 0, 31, 42, 53, 0, 0 ?
>
> For the moment I got the column-major implementation working as
> expected, but I need to add some more tests cases to make sure it is
> working for non-square matrices as well.
>
> Regards,
>
> -Nasos
>

Hey Nasos,

great work. The data in banded matrices is stored either row-by-row 
(row-major), or column-by-column (column-major). This is defined by 
netlib. AFAIK, a diagonal-by-diagonal storage scheme is not supported by 
CBLAS.

Cheers,

Rutger