摘要
The convergence of quasi-Newton methods for unconstrained optimization has at-tracted much attention. Powell proved a global convergence result for the BFGS algorithmusing inexact linesearch which satisfies the Wolfe conditions. Byrd, Nocedal and Yuanextended this result to the convex Broyden class of quasi-Newton methods except the DFPmethod. However, the global convergence of the DFP method, the first quasi-Newtonmethod, using the same linesearch strategy, is still an open question (see ref. [2]).
