Lattice gas automata (LGA) or lattice gas cellular automata (LGCA) methods are a series of cellular automata methods used to simulate fluid flows. It was the precursor to the Lattice Boltzmann methods (LBM). From the LGCA, it is possible to derive the macroscopic Navier-Stokes equations. Interest in the LGCA methods leveled off in the early 1990s, as the interest in the lattice Boltzmann started to rise.

One way of understanding both LGA and LBM is to do like Albert Einstein did with light, imagine that you are the gas particle and then turn, move and maybe collide with other particles. This is also the principle used in turtle graphics by Seymour Papert. LGCA is that simple but can still create this moving gas complexity: