100% usage and simple simulations running very long



my workstation was working normally till yesterday, when even most simple simulations started opening 24 processes and running 20x longer when doing simple FDTD simulations. DEVICE (thermal) is working normally though. What could be the solution, has anyone had this experience?


Hi @milos.jonic
Check the mesh and the PML layers of the FDTD simulation. If you increase the PML layers or the mesh , then , simulation time will be longer.


Thank you, but the thing is that I have not changed anything, and wanted to repeat some results for different visualization. Also Lumerical examples are running very very slow. Maybe it’s some other program interefring with it? Or background processes?


What other applications are you running on the background? Maybe we can try and restart the computer and just try to run FDTD alone? You can also verify what applications you are running on the background aside from FDTD by opening the task manager if you are using Windows by:
Right Click on the Task Bar and Click on Start Task Manager

Or try and check if the resource configuration was changed? We have the this article on the resource manager here; https://kb.lumerical.com/en/index.html?ref_layout_editor_resource_manager.html


Another useful test is to run the simulation with a single process (rather than using all the cores in your computer). Having the single process simulation run at a reasonable speed while running in parallel mode runs slowly suggests that there is another process running in the background of the computer. Another process isn’t too big of a problem when the FDTD engine only uses a single core, but it can cause a big bottleneck when the engine tries to use all the cores.


Thank you very much, in the end it was my “mesh” mistake…