Hello,

I want to run 3D simulations using extremely high grid sizes (2^11 points in the z direction representing a 10 micron physical distance). I have a locally compiled C++ script that I am running on a supercomputer to this end and I wanted to model the 3D propagation of a time varying Gaussian source and its attenuation through space as time progresses.

Now, in order to avoid overloading MATLAB's memory in the generation of an input .h5 file, I have been trying to keep the number of gridpoints in the x and y directions to a minimum. I was wondering, does this have any effect on the output signal in the z direction? I essentially want to generate a signal at z=0 and measure it as it propagates all the way to z=10um, so in principle I don't really need the x and y spaces. However using the 1D or 2D model corresponds to a plane or line source in 3D, and so I am forced to use 3D simulations and have large computation times. I have been trying to keep the number of gridpoints in x and y to a minimum, but have noticed that the wave from my point source keeps bouncing over to the other side of the simulation space (despite my initial source being a few grid points from the PML).

My question is, does it matter what the number of grid points in x and y are if I only care about 3D propagation in the z direction? Is there any benefit in setting Nx or Ny to be anything higher than the lowest possible power of 2 that is still higher than PMLsize+1 or does it not matter?

Thank you!!