[petsc-dev] fixing bugs in resolution of TSEvent's

[Matthew Knepley]

On Mon, Jul 17, 2023 at 10:55 AM Ilya Fursov <ilya.foursov.7bd at gmail.com>
wrote:

> Dear to whom is may concern,
>
> A while ago I tried to use TS events in my time stepping code, and I found
> erroneous behaviour of the event resolution algorithm. For that particular
> example it resulted in long series of extremely small time steps. After
> examining the TSEvent handler code, I found some places with obvious
> errors, but in general it was difficult to figure out exactly what was
> going on, and whether there were other errors.
>
> I decided to try and fix that stuff myself, and my choice was to refactor
> the code from scratch. I abandoned the current (in my opinion, obscure)
> code design of TSEventHandler, and wrote my own version, however using some
> ideas from the original code. The refactoring mostly affected the
> algorithmic part in tsevent.c source file. The original
> constructors/destructors, setters/getters have almost not changed. Also,
> some tiny changes occurred in ts.c and tsadapt.c, where interaction with
> events took place.
>
> I've made a number of tests, ensuring the new code runs smoothly. These
> tests also revealed the current/old petsc code results in lots of errors. I
> didn't take notes on the exact numbers, but from my impression, the old
> code failed in 70%-90% of my tests.
>
> So, I would like to contribute to the project what I've done. Well, I've
> never done such thing before, I hope the process goes smoothly.
> I've read the instructions on submitting the code, and one thing I wanted
> to ask -
> Do I need to start a feature branch from "release" integration branch?
>

No, you can start from main. This is what we do for contributions like this
that are not straight bugfixes.


> On one hand, I only did bug fixing. On the other hand, I've replaced one
> public API function (plus a runtime option), albeit a very small one, which
> didn't work well with the logic of the new code.
>
> Please advise if there might be any other things to consider while
> submitting the code.
>

Once you open the MR, we can review.

  Thanks,

     Matt


> Best Regards,
> Ilya
>


-- 
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/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20230717/7b9e14a9/attachment-0001.html>