[gmx-users] (-13.000000 Total charge should normally be an integer)Facing problem while running gromacs

[kalpana]

Kindly help to understand this error message becz with previous
installation with same setting files, there was no error. The error message
is as follows:

gmx grompp -f  ions.mdp -c model1_solv.gro -p topol.top -o ions.tpr

Setting the LD random seed to 31221519
Generated 330891 of the 330891 non-bonded parameter combinations
Generating 1-4 interactions: fudge = 0.5
Generated 330891 of the 330891 1-4 parameter combinations
Excluding 3 bonded neighbours molecule type 'Protein_chain_A'
Excluding 2 bonded neighbours molecule type 'SOL'

NOTE 1 [file topol.top, line 60959]:
  System has non-zero total charge: -13.000000
  Total charge should normally be an integer. See
  http://www.gromacs.org/Documentation/Floating_Point_Arithmetic
  for discussion on how close it should be to an integer.

Best regards
Kalpana