[petsc-users] Regarding changes in the 3.14 release

[Matthew Knepley]

On Wed, Oct 28, 2020 at 3:13 PM Sajid Ali <sajidsyed2021 at u.northwestern.edu>
wrote:

> Hi PETSc-developers,
>
> I have a few questions regarding changes to PETSc between version 3.13.5
> and current master. I’m trying to run an application that worked with no
> issues with version 3.13.5 but isn’t working with the current master.
>
> [1] To assemble a matrix in this application I loop over all rows and have
> multiple calls to MatSetValuesStencil with INSERT_VALUES as the addv
> argument for all except one call which has ADD_VALUES. Final assembly is
> called after this loop. With PETSc-3.13.5 this ran with no errors but with
> PETSc-master I get :
>
> Object is in wrong state
> [0]PETSC ERROR: Cannot mix add values and insert values
>
> This is fixed by having a flush assembly in between two stages where the
> first stage has two loops with INSERT_VALUES and the second stage has a
> loop with ADD_VALUES.
>
> Did this change result from a bugfix or are users now expected to no
> longer mix add and insert values within the same loop ?
>
We never checked before. You were never supposed to do that. It can break.

> [2] To prevent re-building the preconditioner at all TSSteps, I had the
> command line argument -snes_lag_preconditioner -1. This did the job in
> 3.13.5 but with the current master I get the following error :
>
> Cannot set the lag to -1 from the command line since the preconditioner must be built as least once, perhaps you mean -2
>
> I can however run the application without this option. If this is a
> breaking change, what is the new option to prevent re-building the
> preconditioner ?
>
-1 means never build, but you have not built the preconditioner. Thus you
probably want -2 which means build once and then not again.


> [3] Finally, I’m used the latest development version of MPICH for building
> both 3.13.5 and petsc-master and I get these warnings at exit :
>
> [WARNING] yaksa: 2 leaked handles
> .... (repeated N number of times where N is number of mpi ranks)
>
> Can this be safely neglected ?
>
I don't know.

  Thanks,

     Matt

> Let me know if sharing either the application code and/or logs would be
> helpful and I can share either.
>
> Thank You,
> Sajid Ali | PhD Candidate
> Applied Physics
> Northwestern University
> s-sajid-ali.github.io
>


-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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