[petsc-users] SLEPC matrix Query

[Matthew Knepley]

On Wed, Apr 25, 2018 at 5:10 AM, Savneet Kaur <Savneet.KAUR at cea.fr> wrote:

> Hello,
>
> Warm Regards
>
> I am Savneet Kaur, a master student at University Paris Saclay and
> currently pursuing an internship at CEA Saclay (France).
>
> I have recently started to understand the slepc and petsc solvers, by
> taking up the tutorials for eigenvalue problems. In my internship work I
> have to develop a laplacian matrix from a given transition rate matrix and
> solve it using SLEPC and PETSC and to evaluate the lowest eigenvalue.
>
> I was wondering if I could get some information. I need to diagonalize a
> 2D Laplacian matrix. And writing a code in C and diagonalizing it is easy.
> But I am not getting it how to accommodate with the SLEPC Program. Am i
> suppose to use any packages or it will is done by a loop? Or I need to read
> some other manual to understand how does it work. Please kindly let me know.
>
I would just like to clarify some terminology. "Diagonalize" would usually
mean find all eigenvalues and eigenvectors.
Is this what you mean? Often, SLEPc users want only a portion of the
spectrum since the matrices are enormous.

  Thanks,

     Matt

> The diagonalizing a matrix will be preliminary step of my work.
>
> I will be highly obliged to the the team, if I could get help.
>
> Hoping for a favorable response from your side.
>
> Thank you for the time and consideration.
>
>
> Sincerely,
>
> *Savneet Kaur*
>
> *Intern at DEN/DANS/DMN/SRMP*
>
>
> *CEA - Centre de Saclay ǀ Bâtiment 520 *
>
> *91191 Gif-sur-Yvette Cedex*
>
> *France*
>
> *Tel: +33 (0) 666 749 000*
>
>
> *Email: savneet.kaur at cea.fr <savneet.kaur at cea.fr> *
>
>
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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