bug in InitFDTD 'MaxTime'

[Hale_812]

I use
FDTD = InitFDTD('CoordSystem', 1,'MultiGrid',conf.r/2, 'MaxTime', (60*60*10));
for calculating during 10 hours, each made up of 60 minutes, each made up of 60 seconds.
However, the simulation does not stop after 15+ hours.

In the help it is written that 'MaxTime' is a "real" time of simulation....

is it a simulation model synthetic time after all? or time counter just fails?

[thorsten]

Well maybe the wording is misleading. Meant is only the FDTD time but in seconds. Thus your 10 hours would most likely run longer than the universe is old

If you want to stop at some point, just create the (empty) file "ABORT" in the sim folder and openEMS will stop normally on the next check...

regards
Thorsten

[Hale_812]

really, that should be long. can I ask for additional stop condition in future version if you plan do publish such? Since the real time monitor is already implemented it looks like a natural feature.

[Hale_812]

No, Thorsten, it does not work. Not always. And I don't know why.
I set the stoptime at 1e-7 and see how it runs beyond 1.5e-7.

Sometimes it stops, sometimes not.

WHy do I do this? I excite a resonator with feeding strips and lumped port, a port load is at the other side.
It is inside MUR box. T\When the excitation ends, the field can decay to -45 dB, or maybe -30 dB, then slowly go up and up, probably due to numeric error accumulation. It happens quite often if ports are not terminated with PEC, and I have ports floating in the air (the feed is not rectangular)...

[thorsten]

Hmm, what does the log say. It should be saying at the beginning to how many timestep the simulation was set if you request a max time.

[Hale_812]

1000000000
it is crazy large. looks like a precision problem when timesteps are very small.
timestep is 4.28692e-013
stoptime is 1e-7
there should be only 233267 timesteps, but I already got 789965 steps today.

is something wrong here?

Code: Select all

stoptime=1e-7;
FDTD = InitFDTD('CoordSystem', 0, 'MaxTime', stoptime); %