[gmx-users] energy group error

[Gavin Melaugh]

Hi All

I have set up a topology file and with virtual sites (exerpts below),
whereby my virtual sites only interact with the C3 atoms. I am trying to
construct a PMF wrt one particular C3. This atom I do not want to
interact with the virtual sites at all. I thought the best way to do
this was via energy exclusion groups. So I set up some groups in the
index file (see below), and defined the energy groups like so
energygrps  = vsites vsitex
energygrp_excl = vsites vsitex

but I get the following error

Fatal error:
atoms 415 and 416 in charge group 89 of molecule type 'name' are in
different energy groups
I have no charge group 89 in my molecule. Can someone please suggest
where I might be going wrong.

;Parameter level
[defaults]
; nbfunc    comb-rule     gen-pairs        fudgeLJ     fudgeQQ
     1         3              yes            0.5         0.5

[atomtypes]
;type     mass           charge      ptype     sigma(nm)    
epsilon(kjmol-1)
   CB     12.011000      0.000000       A      0.355000      0.292880
   CA     12.011000     -0.115000       A      0.355000      0.292880
   HC      1.008000      0.115000       A      0.242000      0.125520
   CU     13.019000      0.265000       A      0.350000      0.334720
   NU     14.007000     -0.597000       A      0.325000      0.711280
   CH     13.019000      0.332000       A      0.385000      0.334720
   C3     15.035000      0.000000       A      0.391000      0.669440
   C2     14.027000      0.000000       A      0.390500      0.493712
   VS      0.0           0.0            V      0.0           0.0

[nonbond_params]
;i  j  funct  sigma  epsilon
VS  C3  1      0.1    0.03153


[ cage_1 ]
   1    2    3    4    5    6    7    8    9   10   11   12   13   14   15
  16   17   18   19   20   21   22   23   24   25   26   27   28   29   30
  31   32   33   34   35   36   37   38   39   40   41   42   43   44   45
  46   47   48   49   50   51   52   53   54   55   56   57   58   59   60
  61   75   89  103  117  131  145  159  173  187  201  215
[ tail ]
 416
[ vsites ]
 229  230  231  232  461  462  463  464
[ vsitex ]
 416