I’ve recently observed some strange behavior re: sporadic runtimes for bandstructure simulations. I am calculating the bandstructure for a standard photonic crystal. I have been using the same set of parameters for some time (fairly reasonable, mesh accuracy at 2, 12 PML layers etc, nothing crazy).
A standard run at a single point in k-space previously would take less than one minute, very consistently. Today I attempted to change the material to compare results (previously SiN with user input refractive indez, changing to GaAs which already had a material profile in the drop down.)
When I did this, a single k space point simulation jumped to ~7 minutes. Also, when I run my optimization code, the progress behaves strangely, with some simulations stalling and others progressing until 0-5 seconds remaining and then stalling, as shown below.
Any idea what might be going on? Could a simple change of material cause such a drastic change in runtime?