[gmx-users] PME/Ewald

Andrew Horsfield horsfield at fecit.co.uk
Fri Oct 19 17:24:38 CEST 2001


I am trying to use something other than the cutoff for electrostatics. The
key facts of the simulation are:

1) CG relaxation
2) Net charge on unit cell (-12)
3) 5805 atoms (including solvent)
4) I am using PC running Linux (2.4 kernel, RH 7.1)

And I observe:

a) Ewald causes a core dump.
b) PME give the following output:

>   Starting Energy   = -5.499808236450613e+04
>   F-Norm            =          nan
> Fatal error: ci = -2147483648 should be in 0 .. 391 [FILE nsgrid.c, LINE 214]

Is there something I am doing wrong?

I realize that a net charge for periodic systems leads to infinite
energies, but I assume this is all taken care of in the G=0 term of the
FFT's. Is this correct?



   Andrew Horsfield       e-mail: horsfield at fecit.co.uk 
    FECIT, Hayes Park Central, Hayes End Road, Hayes,
           Middlesex UB4 8FE, United Kingdom.           
   phone: +44-(0)20-8606-4653  FAX: +44-(0)20-8606-4422 

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