Is there any way to get a memory estimate for VASP calculations either directly or indirectly (based on some example calculation)? For example, I would like to be able to predict based on my settings how much memory is needed within about a GB per core.

I have some confusion to calculating the energy for the isolated atom (for constructing the input file): Should I need to change the lattice parameter of my unit cell or whatever I have for my unit cell I can keep that. Also let say I have 4 atoms of one type in my unit cell, so I can consider ...