Accessing the velocity information in LAMMPS custom dump trajectory

[Amir Sadeghi]

Dear MDAnalysis,

I have a pair of LAMMPS DATA (topology) and DUMP (trajectory) files. The DUMP file is formatted as "id type x y z vx vy vz". 

I can successfully load the universe with the following command:

cell = mda.Universe(topology.data,  trajectory.dump, topology_format = 'DATA', format = 'LAMMPSDUMP', lammps_coordinate_convention= 'unscaled', atom_style = "id resid type x y z", dt = 0.01, velocities=True)

chrm = cell.select_atoms('resid 1')

chrm.velocities

 

but I get this error:

--------------------------------------------------------------------------- NoDataError Traceback (most recent call last) ----> 1 chrm.velocities ~/.../MDAnalysis/core/groups.py in __getattr__(self, attr) 2497 # special-case timestep info 2498 if attr in ('velocities', 'forces'): -> 2499 raise NoDataError('This Timestep has no ' + attr) 2500 elif attr == 'positions': 2501 raise NoDataError('This Universe has no coordinates') NoDataError: This Timestep has no velocities

The attached data and trajectory files reproduce this error. Could you please help fix this error?

Kind regards,

Amir

MDAnalysis version: 2.0