Modelling the universe

Procedures used in modeling astrophysical phenomena are discussed. Particular consideration is given to the tree-based techniques for calculating gravity (Appell, 1985; Barnes and Hut, 1986; Benz et al., 1989; Hernquist, 1987) and to the SPH method for calculating the motion of fluid (Gingold and Monaghan, 1977; Lucy, 1977; Monaghan, 1988; Benz, 1988) and to the applications of these methods. It is suggested that the combination of the new methods, together with new computing equipment, has created new possibilities for modeling the evolution of the universe.