[petsc-users] How to set L1 norm as the converge test?

[Matthew Knepley]

On Wed, Sep 24, 2014 at 2:08 PM, Brian Yang <brianyang1106 at gmail.com> wrote:

> Hi all,
>
> For example, I am using LSQR or CG to solve Ax=b.
>
> When we turn on the monitor option of solving the linear system, we could
> see iteration number and residual for each iteration. I believe it's L2
> norm of the objective function?
>
> If yes, is there a way that I could set it to L1 norm for solving the
> system?
>

Yes, you can use
http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPSetConvergenceTest.html
and then use VecNorm() with NORM_1 instead.

  Thanks,

     Matt


> Thanks.
>
> --
> Brian Yang
> U of Houston
>
>
>
>


-- 
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
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