[lammps-users] unsupported data type with Lammps/python

Hello everybody,

i have the following error when i use “lmp.gather_atoms(“x”,1,3)” for ReaxFF data:

WARNING: lammps_gather_atoms: unsupported data type (…/library.cpp:2047)

Is there a detailed manual for python/lammps to know more about scripting with python ? What is “type” and “count” in gather_atoms with python ?

This one is extremely short:

Best regards

two comments:
a) the documentation of the scatter/gather functionality is still missing the refactoring that was applied to the rest of the library and python interface. there was not enough time to get this done so far. if in doubt, just check the comments in the source code for the LAMMPS python module.
b) type refers to constants in the lammps python module to tell python whether you are accessing integer or double data, see https://docs.lammps.org/Python_module.html, count refers to the number of items per atom (e.g. 3 for coordinates and 1 for molecule ids).


also, please make certain you are using the 30 November 2020 version of LAMMPS, since there was a bug in the stable version for the C-library interface for this functionality.

since the python interface follows the c-library interface, it can help to read the documentation for that as well. in fact, in many cases the python documentation merely states that the python module is a wrapper for the corresponding C library function.


Hello Axel,

thanks a lot.

Best regards