[petsc-users] question

[Gideon Simpson]

Ok, so if I’m doing the default Newton Line Search, how would I interpret the 5 and the 20, vis a vis what I would be doing with pencil and paper?

-gideon

> On Oct 24, 2016, at 3:59 PM, Jed Brown <jed at jedbrown.org> wrote:
> 
> Gideon Simpson <gideon.simpson at gmail.com> writes:
> 
>> I notice that if I use -snes_view,
>> 
>> I see lines like:
>>  total number of linear solver iterations=20
>>  total number of function evaluations=5
>> Just to clarify, the number of "function evaluations" corresponds to the number of Newton (or Newton like) steps, and the total "number of linear solver iterations” is the total number of iterations needed to solve the linear problem at each Newton iteration.  Is that correct?  So in the above, there are 5 steps of Newton and a total of 20 iterations of the linear solver across all 5 Newton steps.
> 
> Usually there is one final residual evaluation to declare convergence.
> 
> Also, if you activated a line search, the residual would have been
> evaluated more than once per Newton step.

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