Discreet direction method in nonlinear problem of incoherent scattering spectrum fitting

A new fitting technique based on functional partition by simplexes of the nth order has been developed to determine ionospheric plasma parameters with spectral measurement data from the Irkutsk incoherent scatter radar. The search for functional minimum in this approach adds up to as few model function calculations in each iteration as possible. The algorithm also allows us to simplify the search stop criterion.