Hi, everyon! Why do I still get an error using delete_atoms when I have defined a region ‘fiberbox’: Could not find delete_element region ID (SRC /delete_atoms. CPP :428) .

The script is the folowing.

```
units metal
boundary s s s
variable length equal 60
variable width equal 70
variable height equal 45
region fiberbox block 0 ${length} 0 ${width} 0 ${height}
atom_style bond
timestep 0.001
create_box 1 fiberbox bond/types 1 extra/bond/per/atom 4
pair_style airebo 13.6
pair_coeff * * CH.airebo C
neighbor 0.1 bin
neigh_modify one 20000 page 200000
variable len_unit equal 1.42
variable len_layer equal 3.4
variable phai equal 16.0126/180*PI
variable two equal 2
variable z_layer1 equal 3
variable z_layer2 equal 4
variable z_layer3 equal 3
variable x_num equal 12
variable y_num equal 60
variable std_graphite1 equal 15
variable disloca equal 30
variable std_graphite2 equal ${y_num}-${std_graphite1}-${disloca}
variable num_atom equal 0
variable ntype_atom equal 1
variable z loop ${z_layer1}
label loopz1
variable y loop ${y_num}
label loopy1
variable x loop ${x_num}
label loopx1
if '$((v_y-1)*v_len_unit*sqrt(3)/2)>${width}' then &
'jump fiber_1.lmp break1'
if $(v_y%v_two)==1 then &
'variable xx equal ${len_unit}+($x-1)*${len_unit}*3' &
'variable yy equal ($y-1)*${len_unit}*sqrt(3)/2' &
'variable zz equal ($z-1)*${len_layer}' &
'create_atoms 1 single ${xx} ${yy} ${zz}' &
'variable num_atom equal ${num_atom}+1' &
'variable xx equal ${len_unit}*2+($x-1)*${len_unit}*3' &
'create_atoms 1 single ${xx} ${yy} ${zz}' &
'variable num_atom equal ${num_atom}+1' &
else &
'variable xx equal ${len_unit}/2+($x-1)*${len_unit}*3' &
'variable yy equal ($y-1)*${len_unit}*sqrt(3)/2' &
'variable zz equal ($z-1)*${len_layer}' &
'create_atoms 1 single ${xx} ${yy} ${zz}' &
'variable num_atom equal ${num_atom}+1' &
'variable xx equal ${len_unit}*2.5+($x-1)*${len_unit}*3' &
'create_atoms 1 single ${xx} ${yy} ${zz}' &
'variable num_atom equal ${num_atom}+1'
next x
jump fiber_1.lmp loopx1
next y
jump fiber_1.lmp loopy1
label break1
variable x delete
variable y delete
next z
jump fiber_1.lmp loopz1
mass * 12.01069
group fiber region fiberbox
delete_atoms porosity fiber fiberbox 0.02 ${num_atom} compress yes
```