No atoms in Group

Dear all,

I am trying to run a simulation to deform a polymer system. I have
4 types of atoms in my system and I am reading their configurations
from a data file by 'read_data' command. Now, I wish to tag type 1 and 2
in the same group. Atoms belonging to type 3 and 4 will be assigned
in different groups. And finally type 1,2 and 3 will be tagged under a
same group. I am using the following command lines in my input script.

Dear all,

I am trying to run a simulation to deform a polymer system. I have
4 types of atoms in my system and I am reading their configurations
from a data file by 'read_data' command. Now, I wish to tag type 1 and 2
in the same group. Atoms belonging to type 3 and 4 will be assigned
in different groups. And finally type 1,2 and 3 will be tagged under a
same group. I am using the following command lines in my input script.

----------------------------------------------
group cortex type 1 2
group right_boundary type 3
group dynamic union cortex right_boundary
group left_boundary type 4
------------------------------------------------

Once I let the system to evolve, It shows '0 atoms in group
right_boundary' and '0 atoms in group left_boundary'. Whereas
I have checked several times that there are definitely more than
1 atoms present in those groups.
I could not find the error in my commands. Can you please help me.

how should that be possible? ESP?

i add those lines to the "peptide" example input and it works just fine:

group cortex type 1 2
9 atoms in group cortex
group right_boundary type 3
6 atoms in group right_boundary
group dynamic union cortex right_boundary
15 atoms in group dynamic
group left_boundary type 4
24 atoms in group left_boundary

axel.