Question on dcd/xtc dump files

Hello,

I would like lammps to dump for a range of timesteps (ie. every 10 steps from 1000 to 1500) to a dcd or xtc file. The example given in the documentation uses “every” in dump_modify.

variable s equal logfreq(10,3,10)
dump 1 all atom 100 tmp.dump
dump_modify 1 every v_s first yes

However, “every” cannot be used for these two file formats. Is it possible to create dcd or xtc dump files for a range of timesteps? If so, what will the code be?

Thanks.

Hello,

I would like lammps to dump for a range of timesteps (ie. every 10 steps
from 1000 to 1500) to a dcd or xtc file. The example given in the
documentation uses “every” in dump_modify.

variable s equal logfreq(10,3,10)
dump 1 all atom 100 tmp.dump
dump_modify 1 every v_s first yes

However, “every” cannot be used for these two file formats. Is it possible

that is because every allows arbitrary spacing and
both dcd and xtc formats assume evenly spaced frames.

to create dcd or xtc dump files for a range of timesteps? If so, what will
the code be?

you could do:

run 1000 post no
dump 1 all dcd 10 mydump.dcd
run 500 pre no
undump 1

works for xtc, too.

axel.