[gmx-users] Pull Code problems

[DimitryASuplatov]

Hello,

I am trying to run a pulling simulation with gromacs 4.0.2.

I have appended the following pull code to the mdp file:

;-----------PULL CODE ---------------------

pull	=	umbrella
pull_geometry	= direction
pull_group0	= r_500
pull_group1	= r_535
pull_vec1	= -1.306 1.355 -0.319

Where r_500 is the group I am expecting to be pulled,
      r_535 - the reference (the acid that is in fact in contact with
r_500)

I have left all remaining parameters with default values. 

The problem is that NOTHING HAPPENED! XVG file had 0.0000 throughout
simulation indicating that distance between pull group and reference
group was 0! 

1/ What did I do wrong?
2/ Is there any pull code tutorial for gromacs 4 (not previous
version)? 

Thank you!
SDA