[gmx-users] grompp error - incorrect number of parameters

Lara Bunte lara.bunte at yahoo.de
Thu May 17 15:47:48 CEST 2012



grompp -f em.mdp -p topol.top -c solvated.gro -o em.tpr

I got the error:

Incorrect number of parameters - found 2, expected 4 or 4 for U-B.

I thought that this could be an inconsistency be declaring the functions, but in my topology I have function 4 (for improper dihedrals):

Out of topol.top

[ dihedrals ]
;  ai    aj    ak    al funct            c0            c1            c2            c3
    1     8     6     4     4    180   100

And in my .rtp file in the CHARMM27 force field folder I have:

Out of .rtp file
; bonds  angles  dihedrals  impropers
     1       5          4        4

and in my ffbonded.itp file I have:
[ dihedraltypes ]
; i     j       k       l       func    q0      cq
ON1     NN3A      CN1A       NN2U   4   180   100

So in alle three files, ffbonded.itp, topol.top and the .rtp parametrization file I have the function 4 for the improper dihedrals. 

What is the problem?

Thanks for helping me

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