I’ve noticed that LAMMPS is quite strict with overwriting some command parameters. For example, when you try to do something like:
dump 1 all atom 10 dump.lammpstrj
…
dump 1 all atom 1000 dump2.lammpstrj
you get an error like “Reuse of dump ID”. The command to use is dump_modify, or undump 1 between these two lines.
The same happens when you want to change from a fix nvt to a fix nve; you have to unfix in between.
However, when you want to change the parameters inside a fix nvt, you can do this without much problem, and not even a warning
fix 1 all nvt temp 10.0 10.0 0.1
…
fix 1 all nvt temp 2.0 2.0 0.1
Although this is documented properly, I think that either the second one shouldn’t be allowed, or the first one should (I’d go for this one, but it’s just a personal choice). Any ideas about this?