Hi Sergey

>From your description of the problem, I understand that you want to use
csg_stat to compute
only the non-bonded distributions between specified atoms. Right?

If so.. csg_stat can be used to compute both bonded and non-bonded
distributions separately.
To achieve that one approach would be to specify your molecule topology
that each atom has
unique and different name though there may be multiple atoms of same type.
In your monomer case,
there are four different types of atoms A, B, C, D, and each monomer
consists of 2 As, 3 Bs, 2Cs, and 2 Ds.
Then, in topology, you can specify atom types as A, B, C, D and atom names
are A1, A2, B1, B2, B3, C1, C2,
and D1, and D2. For clarification, you can check out the propane example in
votca-tutorials.

Now with above mentioned topolopy, you can compute non-bonded distributions
between A1-A2, C1-C2, and so on.

Next, if you want to perform coarse-graining and need a reference pair
distributions then first you need to define
a mapping to specify how to determine CG beads configurations from a given
reference all-atom configuration. Then
you can provide this mapping file to csg_stat to determine target
distributions for coarse-graining.
Again you can check out propane example and votca manual to get more
information about how to achieve this.

I hope this helps.

Cheers
Sikandar


On Fri, Dec 13, 2013 at 3:36 AM, Sergey Larin <[email protected]> wrote:

>
> <https://lh5.googleusercontent.com/-Lnkuzcoybi4/UqrTy34LC2I/AAAAAAAAATE/ekUyFfY3bLE/s1600/C-D.dist.png>
> Dear votca users,
>
> I've faced one more problem (not so big, I suppose) in coarsegrainig using
> votca. I've found that csg_stat calculate pair distribution functions
> taking into account atoms that are bonded. As a result the distributions
> have peaks that correspond to bonded interaction (see the picture, in the
> molecule I'm coarsegraining the monomer unit is -C-D-A-D-C-A-B-B-A-B-). It
> is clear for me that it is pretty useless to perform IBI for non-bonded
> interactions using these distribution as target ones. Thus, my question is
> how to say csg_stat to exclude bonded atoms from distribution caclulations?
> Unfortunately, I've found only the way to create exclusion list for
> non-bonded interactions to perform reference simulations for bonded
> interactions distributions.
>
> Thanks in advance.
>
> Sincerely,
> Sergey
>
>
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