fix deform - reamap x option ignored with thermostat

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1

I looked at the dump files. My commands are as follows and I ran the simulation for a short time.

fix deform all deform 1 x erate 0.000001 units box remap v
fix 2 all npt y 0 0 1000 z 0 0 1000 couple none temp ${temperature}

dump deform all custom 1 dump_deform.lammpstrj id mol mass x y z ix iy iz vx vy vz q fx fy fz

Now, I change remap v to remap x and I looked at the dump files. The velocities are the same if you had used the remap v option.

Check whether remap x works correctly:

Comment the following line in the above three lines but change remap v to remap x in fix deform.
fix 2 all npt y 0 0 1000 z 0 0 1000 couple none temp ${temperature}

Now I looked at the dump files. The velocities do not change as expected and the positions are transformed (affine transformation x=x0+vt, where v is the velocity of the moving boundary), This is in accordance with the manual.

However As I mentioned previously, when integration fixes are invoked and when fix deform is used with remap x option it gives the result as remap v option.

I can provide an input script if you want.

Thanks Dr. Steve for your response.

Arun

2

I still don’t understand what you asking. Fix deform remap x will

do the affine transformation you mentioned. The dump file indicates

this is happening. Remap v will only change a velocity when

an atom crosses a periodic/deformed boundary. Depending on

what you are dumping and when, you might not see any atoms

that do that. So I don’t see how you “know” that remap v is

not doing something correctly, with or without time integration.

Steve