[gmx-users] Need help with tabulated non-bonding potential tablep file

[Marcelo Lopez]

Hi all: I'm trying to run a coarse grained system with 3 different
kind of particles, lets call them "A", "B" and "C", and the
interactions between them are set by means of 3 tabulated potentials
(not LJ, totally customized ones). I want to introduce 1-4
interactions with the -tablep optional argument of mdrun. I don't
understand:

1) How exactly to write one tablep.xvg file? 3 or 4 values for each
pair? For example, for the atom indexes 1 and 5, must I write

1   5   0.0   0.0
or
1    5    0.0
?

Or must I write the atom labels?:

A    B    0.0   0.0

2) Must I put only one tablep.xvg file with all the pairs or must I
make one separated table for each kind of 1-4 interaction? For
example:

tablep.xvg (with all the interactions)

or

tablep.xvg, tablep_A_A.xvg, tablep_B_B.xvg, tablep_A_C.xvg, ......

3) mdrun expects the indexes and 1 or 2 values?

4) What's the meaning of the value/s at the right of the 2 indexes for
a not LJ tabulated potential?

5) The pair interactions are scaled or set to zero when using
tabulated non-bonding potentials? I need to set them zero...

Thank you in advance.

Johny.