I have created a sub group and trying to extract atom id using fix store/state and further used loop to extract each id one by one, but in output some of atom id is showing zero. kindly help why some of id are zero. I can dump that group and showing correct atom id without any zero.
---------- Initialize Simulation ---------------------
clear
units metal
dimension 3
boundary p p p
atom_style atomic
atom_modify map array
---------- Create Atoms ---------------------
lattice bcc 2.8553
region box block 0 1 0 1 0 1 units lattice
create_box 1 box
lattice bcc 2.8553 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1
create_atoms 1 box
replicate 3 3 3
mass * 1
---------- Define Interatomic Potential ---------------------
pair_style lj/cut 2.5
pair_coeff * * 1 1
---------- Run Minimization ---------------------
reset_timestep 0
region cod block 0 3 0 3 0 3 units box
group mix region cod
variable total_atom equal count(all)
variable mix_atom equal count(mix)
print ${total_atom}
print ${mix_atom}
dump 15 mix custom 1 dumpcomup.txt id type x y z
run 0
undump 15
fix coord mix store/state 0 id type x y z
label alpha
variable first loop ${mix_atom}
variable id_ext equal f_coord[${first}][1]
print ${id_ext}
variable id_ext delete
next first
jump SELF alpha
output last few line
1
2
3
0
0
0
7
0
9
Total wall time: 0:00:00