## Initialization of simulation Cause the simulation typically are on [[Lattice and periodic system|lattice]], and the centre location are perfectly equilibrium at $T=0$, i.e., fully force balance, so the trick to initialize is, to make some *random displacement* from the initial configuration, or *assign some velocity* following Maxwell-Boltzmann distribution (i.e., distribute the system). Assigning velocity may cause not following momentum conservation, performing some adjustment to velocities may act as a counter force, reaching momentum conservation (like to subtract a linear momentum).