[gmx-users] Position restraints

[Nimmy McNimmerson]

I have a .top file looking like this:

#include "spc.itp"


#include "ffgmx.itp"
#include "lipid.itp"

#define POSRES_LIPID

#include "mylipid.itp"
#include "dppc.itp"

[ system ]
test system


[ molecules ]
; Compound        #mols
DX5                 200
DPPC        200


The #define POSRES_LIPID is used to determine whether to include position restraints in mylipid.itp. However, when I try to run grompp on this (with everything the exact same as before I included the position restraints), I get the error "Topology include file "lipid_posre.itp" not found". If I take out all the position restraints, it works fine and grompp does what is expected. What's going on? I never asked to include this file, I don't even know what lipid_posre.itp is and google has no results on it. I tried adding #include "lipid_posre.itp" at the top of the .top file, just to see what happened, but I got the same error. How am I supposed to add position restraints? The GROMACS manual just says to add them and doesn't mention additional includes, and I added them in the same way that the manual said to.