[gmx-users] changing ewald_rtol

[Johnny Lu]

Hi.

from online manual:

"*ewald-rtol (1e-5)* The relative strength of the Ewald-shifted direct
potential at *rcoulomb* is given by *ewald-rtol*. Decreasing this will give
a more accurate direct sum, but then you need more wave vectors for the
reciprocal sum."

Is it ok to use ewald-rtol=1e-9 for Amber99SB-ILDN forcefield?

Will the sum in reciprocal space become very inaccurate?

Or this will just make the simulation run slower?

Thanks again.