[petsc-dev] Adding VecErrorNormWRMS()

[Abhyankar, Shrirang G.]

> On Apr 30, 2015, at 2:34 PM, "Jed Brown" <jed at jedbrown.org> wrote:
> 
> Lisandro Dalcin <dalcinl at gmail.com> writes:
> 
>> Jed, I would like to make the following changes:
>> 
>> *Add PetscErrorCode VecErrorNormWRMS(Vec U,Vec Y,PetscReal atol,Vec
>> vatol,PetscReal rtol,Vec vrtol,PetscReal *norm).
>> 
>> Any alternative name to suggest?
> 
> Fine, but how would you deal with Shri's ts->is_diff?  And Shri, why did
> you implement that by creating these index sets instead of setting those
> entries of vatol to +Infinity?  
Thanks Jed, I didn't think about that. It certainly seems cleaner to just set the entries of vatol to infinity rather than creating index sets. 

> That's why we have vector weighted norms
> after all.
> 
>> * Implement TSErrorNormWRMS() in terms of VecErrorNormWRMS().

Please note that there is also a variation that uses infinity norm for error calculation.

>> 
>> PS: These changes are preliminary ones, next I want to suggest a
>> mechanism to let TS subtypes to decide how to compute the LTE error
>> (or approximation to it).
> 
> Cool; the current solution is more complicated and less flexible than
> necessary, IMO.

Shri