accuracy and coulombic interactions

Dear Lammps users,
Could you please provide me a link to a formula that relates the accuracy to the ewald parameter (alpha or gewald). Thank you.

Arshia

Dear Lammps users,
Could you please provide me a link to a formula that relates the accuracy to
the ewald parameter (alpha or gewald). Thank you.

the documentation has all the references and details.
all you have to do is read it.

http://lammps.sandia.gov/doc/kspace_style.html

axel.

This is all that I found:

g_ewald = sqrt(-log(accuracysqrt(nscutoff111) /
(2.0
q2))) / cutoff

Could you please confirm it?

Arshia

This is all that I found. Could you please confirm it:

g_ewald = sqrt(-log(accuracysqrt(nscutoffxprdyprdzprd) /
(2.0
q2))) / cutoff;

This is all that I found:

g_ewald = sqrt(-log(accuracy*sqrt(ns*cutoff*1*1*1) /
(2.0*q2))) / cutoff

Could you please confirm it?

are you blind or a moron?

this is a quote from the URL i referenced:

RMS force errors in real space for ewald and pppm are estimated using
equation 18 of (Kolafa), which is also referenced as equation 9 of
(Petersen). RMS force errors in K-space for ewald are estimated using
equation 11 of (Petersen), which is similar to equation 32 of
(Kolafa). RMS force errors in K-space for pppm are estimated using
equation 38 of (Deserno).

it even gives the numbers of the individual
equations of the respective publications.
how much more detail do you want?

axel.

Thanks. I could get my codes running based on your detail reply.