Re: eigensystem

[Patrick Dupre]

gsl_eigen_nonsymmv_workspace
has no member n_evals

issue:

Diagonalizing
double data_3 [] = { 0.0, 0.0, 1.0,
                0.0, 0.0, 0.0,
                0.0, 0.0, 0.0 } ;

I get
eigenvalue = 0 +0i
eigenvector = 
1 +0i
0 +0i
0 +0i
eigenvalue = 0 +0i
eigenvector = 
0 +0i
1 +0i
0 +0i
eigenvalue = 0 +0i
eigenvector = 
-1 +0i
0 +0i
3.00625e-292 +0i


which is wrong.
The last eigenvector is not correct because this matrix is not diagonalizable.

I need to identify such matrices.


===========================================================================
 Patrick DUPRÉ                                 | | email: pdupre@gmx.com
 Laboratoire interdisciplinaire Carnot de Bourgogne
 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
 Tel: +33 (0)380395988
===========================================================================


> Sent: Tuesday, January 19, 2021 at 6:56 PM
> From: "Patrick Alken" <patrick.alken@Colorado.EDU>
> To: help-gsl@gnu.org
> Subject: Re: eigensystem
>
> What do you mean by handle it? According to the documentation, if the
> function cannot compute all eigenvalues, an error code is returned. In
> the case of gsl_eigen_nonsymm, the number of converged eigenvalues is
> stored in w->n_evals.
> 
> Patrick
> 
> On 1/19/21 10:33 AM, Patrick Dupre wrote:
> > Hello,
> >
> > Is there a way to handle the possible error of gsl_eigen_nonsymmv ?
> >
> > For example, when the matrix is not diagonalizable.
> >
> > Thanks
> >
> > ===========================================================================
> >  Patrick DUPRÉ                                 | | email: pdupre@gmx.com
> >  Laboratoire interdisciplinaire Carnot de Bourgogne
> >  9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
> >  Tel: +33 (0)380395988
> > ===========================================================================
> >
> >
> 
> 
>