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nonlinear time dependent problem: set start of newton

Asked by Klemens Frankson

Hi,

While solving a time-dependent, nonlinear pde i have to solve a nonlinear variational problem in every time step.
Is there a possibility to set the start of the newton iteration, which will be used by the nonlinearvariationalsolver, as the solution from the time step before?

Thanks for answers!

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Jan Blechta (blechta) said : 		#1

On Thu, 04 Apr 2013 14:31:09 -0000
Klemens Frankson <email address hidden> wrote:
> New question #225869 on FEniCS Project:
> https://answers.launchpad.net/fenics/+question/225869
>
> Hi,
>
> While solving a time-dependent, nonlinear pde i have to solve a
> nonlinear variational problem in every time step. Is there a
> possibility to set the start of the newton iteration, which will be
> used by the nonlinearvariationalsolver, as the solution from the time
> step before?
>
> Thanks for answers!
>

That's handled automatically as long as you keep old solution (or
other initial guess for next timestep) in a solution function and
supply that function to
  solve(F == 0, u, ...).
Just try to call this line two times in nonlinear-poisson demo...

For NonlinearVariationalProblem interface I expect it works as well.

Jan

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