[Nek5000-users] solver tolerances and norm of residual

[nek5000-users at lists.mcs.anl.gov]

Yes -

p21 is the L2 norm of the divergence, which is the residual
of the pressure solve.

p22 is the norm of the residual for the velocity in the Helmholtz solve. 
If you are solving  H u = ( -h1*Lap + h2) u = f, the iteration stops when

      \int  h1^2 grad u . grad u + h2^2 u^2 dV / vol < tol = p22


Paul




On Wed, 10 Nov 2010, nek5000-users at lists.mcs.anl.gov wrote:

> Hello Neks.
>
> I'm wondering about some details regarding the solvers, namely in regard to the following two tolerances:
>
> P021  DIVERGENCE  tolerance for the pressure solver
> P022  HELMHOLTZ   tolerance for the velocity solver
>
> I assume these tolerances are for some norm on the residual of pressure/velocity.  If so, what is the specific norm?
>
> Thanks.
> --Mike
>
>
>
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