I installed drude implementation files from charmm website. Here's URL: http://mackerell.umaryland.edu/charmm_drude_ff.shtml.

On my linux server Downloads directory, I did the procedure

1. git clone git://git.gromacs.org/gromacs.git

2. cd gromacs

3. git checkout drude

After doing this, I tried using gromacs command, but it shows warning: Unknow left-hand 'drude' in parameter files

there's 5 more warnings showing similar warning like above.

How could I fix that problem?