MPI molecular dynamics on torus

The molecular dynamics method in multiprocessor mode based on a new type of ensemble with constant tension is developed. The new method uses the representation of classical mechanics in T6 = S6 manifold. Six true topological dimensions of the torus surface are represented by six scalars: three relative strains and three shear angles. The separation of spaces, which address the deformation and the coordinates of the particles greatly simplifies the equations of motion. Instead of the stress, the new equations contain the generalized tension forces acting on each atom. The notions of surface and surface forces are absent in new concept based on a new type of ensemble with a constant tension force NfE. A much simpler principle of virtual work provides a number of advantages over the widespread isostress ensemble NtE in molecular dynamics based on Parrinello Rahman method. The method is demonstrated by the example of torsion deformation in aluminium polycrystalline. It is shown that at stresses near the creep threshold, the main mechanism of deformation is the flow of nanocrystals in the grain boundary region.