This is perfectly correct. My question is how do I detect singular matrix since gsl_eigen_nonsymmv does not do it?
> > Your matrix is singular (the first two columns are perfectly correlated, > so your matrix does not have full rank). > > The standard test of singularity is that the determinant cannot be > computed (you try to calculate it, and you get zero or a numerical > error). This post describes the problem and a shortcut: > > https://stackoverflow.com/questions/13145948/how-to-find-out-if-a-matrix-is-singular > > -Alan > > > On 1/19/2021 2:51 PM, Patrick Dupre wrote: > > 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: [email protected] > > 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" <[email protected]> > >> To: [email protected] > >> 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: [email protected] > >>> Laboratoire interdisciplinaire Carnot de Bourgogne > >>> 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE > >>> Tel: +33 (0)380395988 > >>> =========================================================================== > >>> > >>> > >> > >> > > -- > > Alan D. Mead, Ph.D. > President, Talent Algorithms Inc. > > science + technology = better workers > > http://www.alanmead.org > > The irony of this ... is that the Internet is > both almost-infinitely expandable, while at the > same time constrained within its own pre-defined > box. And if that makes no sense to you, just > reflect on the existence of Facebook. We have > the vastness of the internet and yet billions > of people decided to spend most of them time > within a horribly designed, fake-news emporium > of a website that sucks every possible piece of > personal information out of you so it can sell it > to others. And they see nothing wrong with that. > > -- Kieren McCarthy, commenting on why we are not > all using IPv6 > >
