FDTD Computation Time Estimation

How to use openEMS. Discussion on examples, tutorials etc

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kevinlech
Posts: 1
Joined: Fri 09 Oct 2020, 08:38

FDTD Computation Time Estimation

Post by kevinlech » Fri 09 Oct 2020, 08:39

Hi all,

Apologies beforehand if this is a naive question.

I was wondering if I could use the values outputted by the FDTD engine as it set ups and runs the simulation to roughly estimate how long the simulation will take to complete.

In essence, can I use the total number of FDTD cells in my mesh, the length in time steps of the excitation signal, the value of the time step and the speed estimates of seconds/TS ( ex: 143.0 MC/s (1.563e-002 s/TS) ) to calculate how many hours or minutes the simulation will take ? My speed in seconds/TS stays relatively consistent over the course of my simulations.

thorsten
Posts: 1411
Joined: Mon 27 Jun 2011, 12:26

Re: FDTD Computation Time Estimation

Post by thorsten » Sun 11 Oct 2020, 11:00

Hi,

well you get the time it takes to calculate each step one the engine has started and run for a few seconds. Thus you can roughly calculate how long the excitation will take since that number is given during setup as well.
But what nobody can estimate (without any prior experience with the given model) is how long the energy needs to decay. It can be fast or take a very long time (e.g. in case of many high Q resonances).
Thus either you already know how long it will take (by earlier runs) or you just don't know...
What you can (and should) estimate is how long the excitation takes. If that is already too long, you e.g. need to revisit your settings and mesh...

regards
Thorsten

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