[gmx-users] more than 99,999 atoms in conf.gro

[Sikandar Mashayak]

Hi

I am trying to run a simulation with more than 99,999 atoms in a conf.gro
file.
However, when I run grompp I get an error

Fatal error:
Something is wrong in the coordinate formatting of file conf.gro. Note that
gro is fixed format (see the manual)

As suggested in the online manual, I am using the following format to write
conf.gro by a Python script:
{0:5d}{1:5s}{2:5s}{3:5d}{4:8.3f}{5:8.3f}{6:8.3f}.

Could anyone please suggest me how to resolve the issue?

Thanks,
Sikandar