Re: [Cppqed-support] Problem with fuzzy time bugfix

[Andras V. <and...@ui...>]

Dear Raimar,

These trajectory halts are really annoying, especially because the
bugfix in question was introduced just against such halts.
And now you say that it is with the fix that you experience new halts?!

At the moment I don't have much time to look into this in depth, but I
would be more than happy to recant this fuzziness of time, since I've
been feeling uncomfortable with it throughout.

May I ask you to look a bit more into this, and to study also the
occurence of halts before revision #204, and why they occur only
without Hamiltonian evolution? (Though I have some explanation, it's
vague and would be difficult to present here.) Perhaps you can come up
with some better idea then how to solve this.

I will nevertheless try to find time to experiment as well.

Thanks a lot and best regards,
András




On Thu, Apr 26, 2012 at 11:34 AM, Raimar Sandner
<rai...@ui...> wrote:
>
> Dear András,
>
> the bugfix #3482771
>
> https://sourceforge.net/tracker/?func=detail&aid=3482771&group_id=187775&atid=922653
>
> introduces a problem with my script 2ParticlesRingCavityFull. I am comparing
> the branches raimar/private/stable (without the fix) and
> raimar/private/development (with the fix), the testcase is one of my production
> runs:
>
> 2ParticlesRingCavityFull --deltaCSin -10 --minitSin 0.1 --evol single \
>        --kappaCos 0.5 --etaSin 2 --fin2 5 --deltaCCos -10 --precision 6 \
>        --dc 0 --minitCos 0.1 --modeCavSin Sin --T 300 \
>        --cutoffSin 12 --modeCavCos Cos --pinit1 "(0.5 0 0.2 0)" \
>        --pinit2 "(-0.5 0 0.2 0)" --UnotCos -5 --kappaSin 0.5 \
>        --fin1 5 --seed 1001 --UnotSin -5 --Dt 1 --cutoffCos 5
>
> In the development branch, the trajectory comes to a halt almost completely
> around t=90, while stable continues to run. So I cannot use the version with
> the fix at the moment.
>
> The timesteps in development are only slightly smaller, on the order of 10^-5.
> In stable the timesteps are mostly on the order of 10^-4 and only sometimes
> 10^-5.
>
> As the simulation is quite slow I will provide a .sv file for t=89 to better
> reproduce the problem. From there maybe I can find out what is going on in the
> stepper.
>
> Is it true that the bug #3482771 only happens without Hamiltonian? Would it be
> possible to test for that and introduce the time fuzziness only for such
> systems?
>
> Best regards
> Raimar
>
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