initialize per-atom variable by extern data

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1

Hi all,

I'd like to initialize a per-atom variable by extern produced data (individual radius of the particles).
I think there is no fix or similar command in LAMMPS that is able to import that data, right?

So, that's why I am asking here, if anybody can give me some hints or advice, which rough steps I could do for that, respectively which already implemented commands in LAMMPS I could modify for that.

Thanks very much,
Regards

Sebastian

2

Hi all,

I'd like to initialize a per-atom variable by extern produced data
(individual radius of the particles).
I think there is no fix or similar command in LAMMPS that is able to
import that data, right?

you can import the/a radius property via a data file.
just have the appropriate atom style defined.

cheers,
     axel.

3

Hi Axel,

sorry, I think I wasn't precise enough.
I'd like to constantly update this variable on specific timesteps. So the read_data command is probably not working because it's only capable to read in data in the beginning of the simulation but not on runtime...

Any further hints?

Thanks in advance,
Sebastian

4

Hi Axel,

sorry, I think I wasn't precise enough.
I'd like to constantly update this variable on specific timesteps. So the
read_data command is probably not working because it's only capable to read
in data in the beginning of the simulation but not on runtime...

Any further hints?

i would write a custom fix for this purpose.

axel.

5

You can use the set diameter command to set the size
of particles from the input script, on the fly.

If you want to reset individual radii for a zillion particles,
then you'd need to write a command to do that. Doesn't
need to be a fix, could just be a command, like "set" itself.

Steve