Dynamic Group and Fix Rigid

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1

Hi LAMMPS experts,

I have the following script to create a rigid dynamic group.

However, in the beginning of simulation, the dynamic group should not be empty, but I got the error that zero or one atoms are in fix rigid group.

clear
dimension 3
boundary p p p
units metal
variable Home string /home/cnano/HADI/CoarseGrain4/
variable PotDir string /home/cnano/lammps-1Feb14/potentials/
variable Three equal ramp(0,140)
log ${Home}log.txt

#-------------------------Variables-----------------------------------

region box block 0 10 0 10 0 150 units box
create_box 1 box

lattice fcc 4.045
create_atoms 1 region box

#-------------------------Potential--------------------------------------

pair_style eam/alloy
pair_coeff * * ${PotDir}Al_Sheng.eam.alloy Al

#-------------------------Equilibration-----------------------

velocity all create 300 481516
fix 1 all langevin 300 300 0.1 4223352 zero yes
fix 1p all nve
thermo 10
timestep 0.0001
run 1000
unfix 1
unfix 1p
region CG block INF INF INF INF INF 10 move NULL NULL v_Three units box
group CG dynamic all region CG
fix 3 CG rigid/nve single
run 1000

Any help is appreciated at advance.

2

Hi LAMMPS experts,

I have the following script to create a rigid dynamic group.

a "dynamic rigid" group is a contradiction in terms. it doesn't make
any sense. how *could* this work at all?? what would be the purpose?

3

See the group doc page for how dynamics groups
are used. No atoms are assigned to it until
the beginning of a run, which is too late for
your fix rigid command.

So Axel is correct, it makes no sense to use
a dynamic group with fix rigid.

Steve