[lammps-users] Issue with delete atoms command when using different compilers

Dear LAMMPS Users

I’ve noticed a strange behavior when using the delete_atoms command in LAMMPS 29Sep2021. In the manual it states that you can specify a region as NULL to impose the group criteria. This works when compiling lammps by using the mpi MakeFile by default without changing anything. However, using Intel Mpi 2020, when using NULL in the region section it gives back an error “ERROR: Could not find delete_atoms region ID (…/delete_atoms.cpp:428)”. I’m not sure if it is a bug or I’m missing something. I reproduced this error on the same machine just by changing the compiler.

Kind Regards

You must be comparing two different versions of LAMMPS and you are not looking at the version of the manual that corresponds to the stable version.

The option to have a “NULL” region was added to the delete_atoms porosity option in this commit https://github.com/lammps/lammps/commit/fc5920812f9a6a1e7f10f3646cf886828e044bf9
which is available only since the 14 December 2021 patch release version.

This is also reflected in the documentation: please compare the documentation for the stable version:
https://docs.lammps.org/stable/delete_atoms.html to the documentation of the latest release version:


You will see that the option to have a NULL region is only described in the latter, but not in the former.

So this has nothing to do with the compiler or the MPI library, but incorrect observation on your side and looking at the wrong version of the manual.