[petsc-users] KSP Tolerances for SNES

[Dharmendar Reddy]

Aaah...nice saves me work :) . Thanks

On Mon, Jan 20, 2014 at 4:17 PM, Matthew Knepley <knepley at gmail.com> wrote:
> On Mon, Jan 20, 2014 at 3:58 PM, Dharmendar Reddy <dharmareddy84 at gmail.com>
> wrote:
>>
>> Hello,
>>         I want to set KSP Tolerances for an SNES solver for F(X) = 0
>>
>> as absTolKSP = maxval ( norm2F, absTolF_SNES)
>>
>> I am doing the above step based on Corollary 4 in the paper
>>
>> (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10.8477&rep=rep1&type=pdf)
>
>
> It appears that Mike's paper was published before the reference everyone
> uses for this:
>
> S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an inexact
> Newton method", SISC 17 (1), pp.16-32, 1996.
>
> We have it in PETSc:
>
>
> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/SNES/SNESKSPSetUseEW.html
>
>   Thanks,
>
>      Matt
>
>>
>> Since norm2(F) chnages as the simulation progress, how to change the
>> tolerence for the ksp ?
>>
>> I am trying via KSPConvergenceTest by doing the following calls inside
>> the test funciton
>>
>>  call KSPSetTolerances
>>  call KSPDefaultConverged
>>
>> now for the second call i need to pass KSPDefaultConvergedCtx , how do
>> i do this from Fortran ?
>>
>> Thanks
>> Reddy
>
>
>
>
> --
> 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