I am running LAMMPS on Windows 7 in parallel (with the latest version), and also on my Mac (running Mavericks) in serial.
I am running granular simulations, which consist of pouring molecules composed overlapping spheres in to a box (with the Hertzian potential) and then calculating the resulting packing fraction.
When I run identical simulations on both MacOS and Windows, the results are slightly different (about 0.3%) between the two operating systems. Though this is still within error of my method of calculating the packing fraction of the box of particles, it seems strange that the results should be different at all. Both of the simulations are identical (same random seed, same commands in the same order except for the differences in “communicate” and “comm_modify” between MacOS and Windows LAMMPS), and yet the simulations run slightly differently.
Has anyone else seen this, or is there a way of rectifying this? I would greatly appreciate any help!