[gmx-users] Position restraints for two groups

[Sergio Manzetti]

I'd like to add posres on two groups defined in the index file. The index 
file was made with the gro file from the pdb2gmx. I use genpr with the 
input  *gro  file for EM  and the ndx file to generate position restraint 
for one group first and the second in a new genpr session. Then I merge the 
two *itp to one file. However, I get:

Cleaning up temporary file gromppa20162
Fatal error: Invalid order for directive position_restraints, file 
""drg.itp"", line 3


Sergio