[gmx-users] problem with pulling code

[pari lotfi]

Dear all,

I want to use a pull code for pulling a wall with a fixed velocity to
produce a shear flow.
First, Is this method is correct for produce a shear flow? and When I use
pull code in .mdp file, I see these errors:

 WARNING 2 [file md_pull.mdp, line 62]:
   Unknown left-hand 'pull_group1' in parameter file

 WARNING 3 [file md_pull.mdp, line 62]:
   Unknown left-hand 'pull_rate1' in parameter file

 WARNING 4 [file md_pull.mdp, line 62]:
   Unknown left-hand 'pull_k1' in parameter file

I am using Gromacs 4.5.5. Should I change my Gromacs version?

Thanks,

Pari