Count the number of nonrattlers and output their coordination number

[Ann1]

Dear LAMMPS users,

I am trying to compress the simulation box to achieve the closest packing of spherical particles with different sizes and calculate the coordination number of particles with larger than two contacts (nonrattlers).

Could you please tell me how to select those atoms with larger than two contacts and calculate their total coordination number and average coordination number?

Thank you in advance.

Ann

[akohlmey]

@Ann1

Could you please tell me how to select those atoms with larger than two contacts and calculate their total coordination number and average coordination number?

Have you had a careful look at the LAMMPS manual? Specifically:

• compute rattlers/atom command — LAMMPS documentation
• compute coord/atom command — LAMMPS documentation
• compute reduce command — LAMMPS documentation

[Ann1]

Thank you. Yes, I have used all these commands in my input file. I don’t know how to define a dynamic group, such as nonrattlers in large groups and nonrattlers in small groups. Then I can compute average coordination number of these nonrattlers. Through post-processing (matlab; for i =1:N … if c_rattler <1…), it can be achieved. I would like to know If LAMMPS can directly calculate them.

Ann

[akohlmey]

@Ann1

I don’t know how to define a dynamic group

This is explained in the documentation for the group command.

@Ann1

I would like to know If LAMMPS can directly calculate them.

What LAMMPS can provide directly, is shown in the documentation.
There are no features in LAMMPS without documentation.

[Ann1]

I will read relevant commands carefully. Thank you so much for your promptly reply, Dr. Akohlmey