[gmx-users] .top file incoherent with the values in the ffbonded.itp file

sreeta.g sreetasai at gmail.com
Fri Jun 29 21:55:25 CEST 2012


Hello
My A.gro file is:
 1PvB     CB    1   3.109   2.784   0.803  0.0000  0.0000  0.0000
    1PvB    HB1    2   3.156   2.880   0.843  0.0000  0.0000  0.0000
    1PvB    HB2    3   2.997   2.797   0.819  0.0000  0.0000  0.0000
    1PvB    HB3    4   3.129   2.765   0.693  0.0000  0.0000  0.0000
    1PvB     CA    5   3.173   2.673   0.879  0.0000  0.0000  0.0000
........... (contd.)

My ffbonded.itp file has:
[ bondtypes ]
;   i    j   func   b0(bond length)  kb (force const)
   CB    HB1  1    0.11       284512
   CB    HB2  1    0.11       284512
   CB    HB3  1    0.11       284512.0
... (contd)

[ angletypes ]
;  i     j    k   func     th0    cth
  HO    OH   CA    1       105    320
  CA    CB   CA    1       109.45 482.3
  CB    CA   CB    1       109.45 482.3
  OH    CA   CB    1       107.8  460  
....... (contd)

[ dihedraltypes ]
;  i    j    k    l   func    RB coefficients
   OH  OH   CA   CB        3     3.00000    9.00000 0.00000   -12.00000  
0.00000   0.0000 ;
   CA  CB   CA   CB        3     5.75000   17.25000 0.00000   -23.00000  
0.00000   0.0000 ;
..... (contd)

However, my topol.top file looks like this:
[ bonds ]
;  ai    aj funct            c0            c1            c2            c3
    1     2     1
    1     3     1
    1     4     1
    1     5     1
    1    12     1
........(contd)

[ angles ]
;  ai    aj    ak funct            c0            c1            c2           
c3
    2     1     3     1
    2     1     4     1
    2     1     5     1
    2     1    12     1
    3     1     4     1
    3     1     5     1
......... (contd)

[ dihedrals ]
;  ai    aj    ak    al funct            c0            c1            c2           
c3            c4            c5
    2     1     5     6     3
    2     1     5     7     3
    3     1     5     6     3
    3     1     5     7     3
    4     1     5     6     3
    4     1     5     7     3
....... (contd)

I have two issues:
1) I have mentioned the bond lengths and bond constants in the [bondtypes]
and [angletypes ]directory of the ffbonded.itp file, however in the [bonds]
[ angles ]directory in the topol.top file the Ryckaert-Bellemans
coefficients are used, which are assigned as blanks. This is giving the
error No default Ryckaert-Bell. types (multiple times). 
2) Also, the RB coefficients mentioned in the [dihedraltypes] of the
ffbonded.itp are not used in the [dihedrals] directory of the topol.top
file. This is again writing blanks for the RB coefficients.
What is the issue and why is my topl.top file inconsistent with the inputs
given in the ffbonded.itp file?
Thank You
Sreeta 

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