A non-linear optimization algorithm which uses a combined strategy of linear approximation and
gradient-descent to locate a minimum, actively switching between the two according to the success or failure of the linear approximation: a so-called model-trust region approach (see Levenberg, 1944; Marquardt, 1963; Bishop, 1995; Shepherd, 1997; Press et. al., 1992).
See also, the
Neural Networks chapter.