[lammps-users] reax and LAMMPS

Yes, it sounds like you are requesting more memory than your computer can
provide. You can get some idea of how much memory you are requesting using
the size command. For example, when I compile LAMMPS with ReaxFF on my Apple
laptop I get:

size ../lmp_mac_mpi
__TEXT __DATA __OBJC others dec hex
1810432 1800335360 0 237568 1802383360 6b6e3000

This tells me that I am allocating about 1.8 GB. If I compile without the
ReaxFF library I get:

size ../lmp_mac_mpi
__TEXT __DATA __OBJC others dec hex
1605632 61440 0 229376 1896448 1cf000

Quite a difference. Instead of trying to shoehorn the ReaxFF arrays into
some predefined limit, I suggest your try one of these approaches:

1. Use fewer atoms
2. Use more processors.

The nice thing about these solutions is that, not only does your code
compile and run, it runs a lot faster.