Figure 3 Level curves and paths of the optimization algorithms for function f5. The path of three considered algorithms is shown in Figure 3. Here, theoretical results of the influence of the orthogonality degree of matrix learning vectors on the convergence rate of the method are confirmed. The BFGS_V method performs forced orthogonalization, which improves the result of the BFGS method. The trajectories of the methods are listed in Tables Al—A3 of Appendix A (the trajectory of the DFP method is shown partially).