[lammps-users] Dump output to 16 significant figures

Dear all,

Sorry to ask such a simple question but I am having some problems with my simulations. I am coupling a fluid dynamics code to Lammps (Liggghts) and was told it would be best to ask about my problem here.

My problem is that it seems that the dump command writes the particle coordinates to 6 significant figures but my input data is accurate to 16 s.f. and I need my output to be the same otherwise I cannot see any changes to the particle positions in each timestep. My timesteps are very small, but there is very little I can do about this, so I really need a way to output the particle positions from Lammps accurate to 16 significant figures.

I have tried using the SI and LJ unit systems but the result is the same: no change in position between DEM timesteps. I read that the precision keyword can be used with the dump_modify command when using the XTC unit system but was hoping that it may be possible to do something similar with either LJ or SI units as well.

If anyone has any advice or suggestions I would really appreciate the help!

Best regards,


Dear Paul,

  To increase the number of significant figures in the dump, recently I used:

dump_modify 1 format "%d %d %d %20.13f %20.13f %20.13f"

You may want to try on similar lines.

btw, my units are real.