return minimum/maximum value of the function To find the minimum on a range, first set this range via the SetRange function If a vector x of coordinate is passed it will be used as starting point for the minimum. In addition on exit x will contain the coordinate values at the minimuma If x is NULL or x is inifinity or NaN, first, a grid search is performed to find the initial estimate of the minimum location. The range of the function is divided into fNpx and fNpy sub-ranges. If the function is "good" (or "bad" ), these values can be changed by SetNpx and SetNpy functions Then, a minimization is used with starting values found by the grid search The minimizer algorithm used (by default Minuit) can be changed by callinga ROOT::Math::Minimizer::SetDefaultMinimizerType( ".." ) Other option for the minimizer can be set using the static method of the MinimizerOptions class