• dump()

    write configuration to trajectory XYZ file. By default filename is, coordinates are folded. DumpXYZ works also for Multiple communicators.


  • filename Name of trajectory file. By default trajectory file name is

  • unfolded False if coordinates are folded, True if unfolded. By default - False

  • append True if new trajectory data is appended to existing trajectory file. By default - True

  • length_factor If length dimension in current system is nm, and unit is 0.23 nm, for example, then length_factor should be 0.23 Default: 1.0

  • length_unit It is length unit. Can be LJ, nm or A. By default - LJ

  • store_pids

    True if you want to store pids as fastwritexyz does. False otherwise (standard XYZ) Default: False

  • store_velocities

    True if you want to store velocities. False otherwise (XYZ doesn’t require it) Default: False


writing down trajectory

>>> dump_conf_xyz =, integrator, filename='')
>>> for i in range (200):
>>>   dump_conf_xyz.dump()

writing down trajectory using ExtAnalyze extension

>>> dump_conf_xyz =, integrator, filename='')
>>> ext_analyze = espressopp.integrator.ExtAnalyze(dump_conf_xyz, 10)
>>> integrator.addExtension(ext_analyze)

Both examples will give the same result: 200 configurations in trajectory .xyz file.

setting up length scale

For example, the Lennard-Jones model for liquid argon with \(\sigma=0.34 [nm]\)

>>> dump_conf_xyz =, integrator, filename='', \
>>>                                       unfolded=False, length_factor=0.34, \
>>>                                       length_unit='nm', store_pids=True, \
>>>                                       store_velocities = True, append=True)

will produce with in nanometers, integrator,, unfolded=False, length_factor=1.0, length_unit='LJ', store_pids=False, store_velocities=False, append=True)
  • system
  • integrator
  • filename
  • unfolded (bool) –
  • length_factor (real) –
  • length_unit
  • store_pids (bool) –
  • store_velocities (bool) –
  • append (bool) –
Return type: