# Krylov parameters

Hi, I'm new but I hope to do it properly...

I'm trying to solve a problem but I can not control the parameters of the solver... in dolfin 1.1.0

focusing on the problem:

[...]

problem = LinearVariation

solver = LinearVariation

solver.

solver.

prm = solver.

prm[

prm[

prm[

prm ['gmres'

prm[

prm[

info(

set_

solver.solve()

[...]

...It runs ok and tells me...

_______

[...]

Solving linear variational problem.

Applying boundary conditions to linear system.

Applying boundary conditions to linear system.

Solving linear system of size 3298 x 3298 (PETSc Krylov solver).

PETSc Krylov solver starting to solve 3298 x 3298 system.

PETSc Krylov solver (gmres, jacobi) converged in 169 iterations.

_______

If I fixed maximum_iterations to 10,

Why my problem converged? Why do not solver stops in 10 iterations and diverge? Why it runs to 169 iterations?

When I read info parameters, the values are ok, but later the solver are not taking into account these parameters!!

When I change absolute and relative tolerance the number of iterations remains constant... in 169, obtaining the same result...

it not runs well...

I would be very grateful if someone could tell me what I'm doing wrong or explain me what is happening??

thx

## Question information

- Language:
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- Status:
- Answered

- Assignee:
- No assignee Edit question

- Last query:
- 2013-05-14

- Last reply:
- 2013-05-22

Johannes Ring (johannr) said : | #1 |

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