(cosmological model combining analytic and other methods)
Semi-analytic model (SAM) is a broad term covering models of
the universe incorporating both analytical methods along with
other methods such as N-body simulations or hydrodynamics
simulations or EPS merger trees, a method of modeling the merger
of dark matter halos and galaxy formation.
Use of the term SAM basically indicates the use of some subgrid-scale physics
(consisting of known analytic models of the appropriate scale)
to make simulation of a larger volume tractable.