I was wondering if anyone has any experience running LAMMPS on a Mac cluster. I have devised a simple test case with flexible water, where I conducted the simulations on our Mac cluster as well as our Opteron cluster. In this case, I get the exact same energies after a 1000 timesteps.
However, if I devise a new test case where I use SHAKE bond constraints, I get different energies that are significantly off …
For the opteron cluster, using the Portland Group (PG) compiler, the total energy of the system is -4973.8062.
For the mac cluster, using GCC and XLC compilers, the total energy of the system is -4973.8497 for both compilers.
Does anyone have any insight into why this may be happening?