Dump Compute Reduce

LAMMPS LAMMPS General Discussion
1

Hi I am trying to dump to a txt file the maximum bond distance every N timesteps in my simulation. I use these lines of commands to calculate it

compute 1 all property/local batom1 batom2
compute 2 all bond/local dist
compute 3 all reduce max c_1[1] c_1[2] c_2 replace 1 3 replace 2 3

In the Thermodynamic output everything seems to be ok and the properties are printed into the screen with the following command:
thermo_style custom step etotal ke pe temp press vol lx density c_3[1] c_3[2] c_3[3]

I try to dump it to a file like that
dump max_bond all custom 100 max_bond.data c_3[1] c_3[2] c_3[3]

and I get an error : ERROR: Dump custom compute does not compute per-atom info

When I change custom to local
dump max_bond all local 100 max_bond.data c_3[1] c_3[2] c_3[3]

I get the error: ERROR: Dump local compute does not compute local info

Is anyone able to help? Thank you!

2

Yes, and for a good reason. Dumps are for per-atom data, while the property you want to output are a global scalars. So what you are doing makes no sense. If you want to output global properties you have use fix print or fix ave/time or similar or just extract them from the thermo output part of the log file using python (see tools/python).

3

Thank you!