[gmx-users] PME/Ewald

[Andrew Horsfield]

> To check quickly whether it is the charge you can ofcourse replace 12
> solvents by Na+ (using genion).

I have tried including 12 Na+ ions. The warning about the charges
disappeared, but the PME mesh still failed.

I have had success with PME with a charged small cell without solvent.

Thus the problem is not the charge.

Maybe there is some problem with my input file. It contains:

; OPTIONS FOR ELECTROSTATICS AND VDW =
; Method for doing electrostatics =
coulombtype              = PME
rcoulomb-switch          = 0
rcoulomb                 = 1.0
; Dielectric constant (DC) for cut-off or DC of reaction field =
epsilon-r                = 1
; Method for doing Van der Waals =
vdw-type                 = Cut-off
; cut-off lengths        =
rvdw-switch              = 0
rvdw                     = 1.0
; Apply long range dispersion corrections for Energy and Pressure =
DispCorr                 = No
; Spacing for the PME/PPPM FFT grid =
fourierspacing           = 0.2
; FFT grid size, when a value is 0 fourierspacing will be used =
fourier_nx               = 0
fourier_ny               = 0
fourier_nz               = 0
; EWALD/PME/PPPM parameters =
pme_order                = 4
ewald_rtol               = 1e-05
epsilon_surface          = 0
optimize_fft             = no

Cheers,

Andrew