[lammps-users] ewald screening parameter

Hi all. I'm trying to figure out what the Ewald screening parameter is (I've also heard it called the convergence, or splitting parameter) given the chosen precision. From looking through the code I think the g_ewald (G vector) is what I'm looking for - the thing that controls the width of the screening gaussian. I think the units are right - one over length. Is the value of the G vector printed in the output consistent with the units chosen in the input?

Yes, that is what g_ewald is. I recall there is a factor
of sqrt(2) difference in the definition of g_ewald between
Ewald and PPPM, so it's not an absolute value, just a numeric one.
Don't know what you mean by units chosen in the input.
The input precision and cutoff are transformed into a g_ewald


Thanks Steve. The question I have about units is, if I define my units as real in my input, is the value of the G vector printed to the log file in inverse Angstroms? From what I can sort out the units of G vector is consistent with units chosen in the input file.

Quoting Steve Plimpton <[email protected]>:

yes, I think that's correct.