fix setforce

Dear All,
I am using LAMMPS (14 Feb 2014) and have some questions about fix setforce simulation:
I want to fixed the atoms in the outmost region to make a fixed boundary and use ‘fix setforce’ command, such as:
fix 1 cold setforce 0.0 0.0 0.0 #to fix the atoms in group ‘cold’
And then, I want to keep the atoms in group ‘cold’ at 0.01K at the same time. Could I use the following two commands together?
fix 1 cold setforce 0.0 0.0 0.0
fix 2 cold nvt temp 0.01 0.01 0.1
Although, the two commands running is ok, and I didn’t get any error. However, I am not sure whether ‘fix setforce’ will affect the time integration and the update of the position and the velocity for atoms in the group?

Thank you very much for your answer
Best regards,

Dear All,
I am using LAMMPS (14 Feb 2014) and have some questions about fix setforce‍
simulation:
I want to fixed the atoms in the outmost region to make a fixed boundary and
use 'fix setforce' command, such as:
fix 1 cold setforce 0.0 0.0 0.0 #to fix the atoms in group 'cold'‍
And then, I want to keep the atoms in group 'cold' at 0.01K at the same
time. Could I use the following two commands together?
fix 1 cold setforce 0.0 0.0 0.0‍
fix 2 cold nvt temp 0.01 0.01 0.1‍
Although, the two commands running is ok, and I didn't get any error.
However, I am not sure whether 'fix setforce' will affect the time
integration and the update of the position and the velocity for atoms in the
group?

yes it does. if you want to have atoms move with a given kinetic
energy that corresponds a particular temperature, but not leave their
general location, you cannot use setforce. setforce 0 0 0 wipes out
all computed forces and thus, provided the atoms have *no* kinetic
energy, they will remain immobile. what appears to me that you want is
to use fix spring/self, which will allow atoms to move, but restrain
them to their initial location with a harmonic potential.

axel.