March 22, 2021 at 6:55 pmTaylor RobertsonAnsys Employee
When you run a simulation in FDTD the job manager window shows the auto shutoff level, which is a measure of the energy left in the simulation window. This value is used to determine if the calculation can be stopped before the end of the simulation time. In some cases it might happen that the job manager shows the value of the auto shutoff to be 1 or some value smaller than 1 but larger than the minimum from the simulation settings (1e-5 by default) and then the simulation suddenly stops. This does not necessarily mean that the simulation did not reach the condition for early shutoff. If the log file created during the simulation shows the following message:
“Early termination of simulation, the autoshutoff criteria are satisfied.”
your simulation has stopped properly. The reason why you might encounter this unexpected termination is because the condition for ending the simulation was reached before the job manager had time to update the displayed value for the auto shutoff level. This value is updated every ~1% of the simulation time; therefore, if the simulation time (from the simulation settings) is long compared to the time it takes the energy to leave the simulation window, you might not be able to see the shutoff level decreasing nicely to the minimum. This, however, does not mean that there is something wrong with the simulation, it is just a consequence of the way the information in the job manager is updated.
It is not possible to modify the job manager settings for showing the auto shutoff level, for example to be every 0.1% of the simulation time. However, you have control over the internal sample time for the auto shutoff in the “Advanced options” tab of the “Edit FDTD simulation” window. The default setting is to internally check the auto shutoff conditions every 100 time steps of the simulation; usually, this is a very small fraction of the total simulation time, smaller than 1%, and so the program will internally check the condition for autoshutoff more frequently than what you see in the job manager.Viewing 0 reply threads
Ansys Innovation Space
- You must be logged in to reply to this topic.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.Trending discussions
- “Import optical generation” or “delta generation rate”?
- Why am I getting “process exited without calling finalize”, and how do I fix it?
- Error on Lumerical device
- Using a license file on a new license server
- Error: addfdtd is not a valid function or a variable name
- Ansys Insight: Diverging Simulations
- Ansys Insight: Transmission results greater than one
- Ansys Insight: About override mesh in FDTD: its use and settings
- Is there a Lumerical script command to output the Simulation and Memory requirements?
- Ansys Insight: Convergence issues in CHARGE
Top Rated Tags
© 2023 Copyright ANSYS, Inc. All rights reserved.Ansys does not support the usage of unauthorized Ansys software. Please visit www.ansys.com to obtain an official distribution.