Re: [Help-gsl] test release for GSL 2.2

[Peter Johansson]

Thanks. That's very useful.

Cheers,
Peter

On 08/30/2016 11:30 AM, Patrick Alken wrote:
> Ah yes that helps narrow it down. The behavior of 
> gsl_linalg_cholesky_decomp has changed slightly. Before (2.1 and 
> prior) the work was done using the lower triangle and then the lower 
> triangle was copied to the upper triangle to have a fully symmetric 
> matrix.
>
> However, in order to use the new condition number estimation, 
> gsl_linalg_cholesky_rcond, it needs to compute the norm of the 
> original matrix. Therefore, now the cholesky factor is stored in the 
> lower triangle and the upper triangle contains the original matrix.
>
> This is more in line with the lapack storage scheme, although I 
> realize it will break a few codes, such as yours.
>
> One quick fix would be to add a call to gsl_matrix_transpose_tricpy 
> after your cholesky decomp call to copy the cholesky factor to the 
> upper triangle.
>
> Long term it would be better to only reference the lower triangle.
>
> Sorry for the trouble :/
>
> On Aug 29, 2016 5:32 PM, Peter Johansson <address@hidden> wrote:
>
>     Sorry I missed to answer this question.
>
>
>     On 08/30/2016 09:27 AM, Peter Johansson wrote:
>     > Does your code work with GSL 2.1?
>
>     Yes, I get different behaviour when I link with GSL 2.1 and GSL
>     2.1.91.
>     That's why I'm concerned that something has changed in GSL.
>
>     Cheers,
>     Peter