[petsc-users] Saving solution with monitor function

[Matthew Knepley]

On Tue, Dec 13, 2022 at 8:40 AM Guglielmo, Tyler Hardy via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Hi all,
>
>
>
> I am a new PETSc user (and new to MPI in general), and was wondering if
> someone could help me out with what I am sure is a basic question (if this
> is not the appropriate email list or there is a better place please let me
> know!).
>
>
>
> Basically, I am writing a code that requires a solution to an ODE that
> will be used later on during runtime.  I have written the basic ODE solver
> using TSRK, however I haven’t thought of a good way to store the actual
> solution at all time steps throughout the time evolution.  I would like to
> avoid writing each time step to a file through the monitor function, and
> instead just plug each time step into an array.
>
>
>
> How is this usually done?  I suppose the user defined struct that gets
> passed into the monitor function could contain a pointer to an array in
> main?  This is how I would do this if the program wasn’t of the MPI
> variety, but I am not sure how to properly declare a pointer to an array
> declared as Vec and built through the usual PETSc process.  Any tips are
> greatly appreciated
>

I think this is what TSTrajectory is for. I believe you want
https://petsc.org/main/docs/manualpages/TS/TSTRAJECTORYMEMORY/

  Thanks,

      Matt


> Thanks for your time,
>
> Tyler
>
>
>
> +++++++++++++++++++++++++++++
>
> Tyler Guglielmo
>
> Postdoctoral Researcher
>
> Lawrence Livermore National Lab
>
> Office: 925-423-6186
>
> Cell: 210-480-8000
>
> +++++++++++++++++++++++++++++
>


-- 
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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