[gmx-users] x2top

[Bernhard Knapp]

Dear Users

I tried to use the x2top function of gromacs 4 on a sugar-molecule. But 
the gromacs says that it requests the ffgmx.n2t library which can not be 
found in the default directory. I searched in the whole system but could 
not find it. Therefore I also searched on an other system with gromacs 
3.3 and copied the file form there to the system with gromacs 4. 
Unfortunately it comes up with the next request as below:
-------------------------------------------------------
Program x2top, VERSION 4.0
Source code file: futil.c, line: 527

Fatal error:
Library file ffG43a1.n2t not found in current dir nor in default 
directories.
(You can set the directories to search with the GMXLIB path variable)
-------------------------------------------------------
But I could not find this file neigther on the gromacs 4 nor on the 
gromacs 3.3 system ...

Where can I get all those n2t files from? Or am I doing something wrong? 
My command is simply:
x2top -f sed.pdb -o sed.top -ff select
with forcefield 0:GROMOS96 43a1 force field
if i use 5: OPLS-AA/L it writes
"Generating bonds from distances...
atom 0" to the command line and gets stuck

where sed.pdb contains only
HETATM    1  CAA DRG     1      -8.720   2.440  -1.910  1.00 
20.00             C
HETATM    2  OAB DRG     1      -8.220   1.420  -2.790  1.00 
20.00             O
HETATM    3  CAC DRG     1      -9.020   0.470  -3.380  1.00 
20.00             C
HETATM    4  OAD DRG     1      -8.430  -0.270  -4.170  1.00 
20.00             O
HETATM    5  CAF DRG     1     -10.540   0.220  -3.190  1.00 
20.00             C
HETATM    6  OAE DRG     1     -11.330   1.410  -3.060  1.00 
20.00             O
HETATM    7  CAG DRG     1     -10.840  -0.720  -2.000  1.00 
20.00             C
HETATM    8  OAH DRG     1     -10.270  -0.190  -0.800  1.00 
20.00             O
HETATM    9  CAI DRG     1     -10.330  -2.150  -2.280  1.00 
20.00             C
HETATM   10  OAJ DRG     1     -10.940  -2.650  -3.470  1.00 
20.00             O
HETATM   11  CAK DRG     1     -10.620  -3.170  -1.170  1.00 
20.00             C
HETATM   12  OAL DRG     1     -11.900  -2.940  -0.570  1.00 
20.00             O
HETATM   13  CAM DRG     1      -9.550  -3.150  -0.060  1.00 
20.00             C
HETATM   14  OAN DRG     1      -9.840  -4.150   0.920  1.00 
20.00             O


Is this a problem of gromacs or am I really missing libraries or is the 
input somehow bad?


sincerely
Bernhard