# Eigenvalue Solver Problems

Hi,

I try to solve an eigenvalue problem with the format " a = inner(nabla_

1. I don't know how to use other eigenvalue solvers except the default one

What I know right now is to do as "eigensolver = SLEPcEigenSolve

2. When I set v_ext as 1/r (r is the distance from the point to the mesh center), it takes forever to get the results; and if I set v_ext as some other more common funtions (such as r, constant), it is pretty fast to solve.

I have changed the center a little bit to avoid the infinity, but it still takes very long, why?

thanks,

Houdong

## Question information

- Language:
- English Edit question

- Status:
- Solved

- For:
- DOLFIN Edit question

- Assignee:
- No assignee Edit question

- Solved by:
- Houdong Hu

- Solved:
- 2013-03-16

- Last query:
- 2013-03-16

- Last reply:
- 2013-03-13

## This question was reopened

Marie Rognes (meg-simula) said : | #1 |

1. Read the documentation for the eigensolver (for instance for v 1.1.0):

2. This is not really a DOLFIN related question.

Houdong Hu (vincehouhou) said : | #2 |

Thanks,