Output total force between particles in HOOMD?

[zhang...@gmail.com]

Hi all,

Is there possible to output total force between particles in HOOMD?

many thanks!

Yunhan

[Brandon Butler]

Hey Yunhan,

Yes, you can access the total force acting on a particle through the local snapshot see (https://hoomd-blue.readthedocs.io/en/v3.4.0/module-hoomd-data.html#hoomd.data.ParticleLocalAccessBase).

If you want force specific look at the forces property of a potential object (https://hoomd-blue.readthedocs.io/en/v3.4.0/module-md-force.html#hoomd.md.force.Force.forces) or the local force buffers if you know the force has not changed since it was last evaluated (https://hoomd-blue.readthedocs.io/en/v3.4.0/module-md-force.html#hoomd.md.force.Force.cpu_local_force_arrays).

Best,

Brandon

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Brandon Butler
MolSSI Fellow
PhD Candidate, Chemical Engineering and Scientific Computing | Glotzer Lab, University of Michigan
Email: butl...@umich.edu

[zhang...@gmail.com]

I see,  thanks a lot Brandon!

[Sebastian R]

Hi, is this still valid in 4.0? I'm adding individual forces using 
logger = hoomd.logging.Logger()
logger.add(coulomb, quantities=['energies', 'forces'])
but I have no idea how to add the net force on particle 0, for example (how to integrate  hoomd.data.ParticleLocalAccessBase with logging). 

Thanks!

Sebastian