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Powell's dog leg method, also called Powell's hybrid method, is an iterative optimisation algorithm for the solution of non-linear least squares problems, introduced in 1970 by Michael J. D. Powell. [1] Similarly to the Levenberg–Marquardt algorithm, it combines the Gauss–Newton algorithm with gradient descent, but it uses an explicit trust ...
The general idea behind trust region methods is known by many names; the earliest use of the term seems to be by Sorensen (1982). [1] A popular textbook by Fletcher (1980) calls these algorithms restricted-step methods. [2]
LMA can also be viewed as Gauss–Newton using a trust region approach. The algorithm was first published in 1944 by Kenneth Levenberg, [1] while working at the Frankford Army Arsenal. It was rediscovered in 1963 by Donald Marquardt, [2] who worked as a statistician at DuPont, and independently by Girard, [3] Wynne [4] and Morrison. [5]
Use of merit functions, which assess progress towards a constrained solution, or filter methods. Trust region or line search methods to manage deviations between the quadratic model and the actual target. Special feasibility restoration phases to handle infeasible subproblems, or the use of L1-penalized subproblems to gradually decrease ...
In a quasi-Newton method, such as that due to Davidon, Fletcher and Powell or Broyden–Fletcher–Goldfarb–Shanno (BFGS method) an estimate of the full Hessian is built up numerically using first derivatives only so that after n refinement cycles the method closely approximates to Newton's method in performance. Note that quasi-Newton ...
It addressed the instability issue of another algorithm, the Deep Q-Network (DQN), by using the trust region method to limit the KL divergence between the old and new policies. However, TRPO uses the Hessian matrix (a matrix of second derivatives) to enforce the trust region, but the Hessian is inefficient for large-scale problems. [1]
Powell's method, strictly Powell's conjugate direction method, is an algorithm proposed by Michael J. D. Powell for finding a local minimum of a function. The function need not be differentiable, and no derivatives are taken. The function must be a real-valued function of a fixed number of real-valued inputs.
In numerical optimization, the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm is an iterative method for solving unconstrained nonlinear optimization problems. [1] Like the related Davidon–Fletcher–Powell method, BFGS determines the descent direction by preconditioning the gradient with curvature information.