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The Barzilai-Borwein method [1] is an iterative gradient descent method for unconstrained optimization using either of two step sizes derived from the linear trend of the most recent two iterates. This method, and modifications, are globally convergent under mild conditions, [ 2 ] [ 3 ] and perform competitively with conjugate gradient methods ...
When the damping factor is large relative to ‖ ‖, inverting + is not necessary, as the update is well-approximated by the small gradient step [()]. To make the solution scale invariant Marquardt's algorithm solved a modified problem with each component of the gradient scaled according to the curvature.
The geometric interpretation of Newton's method is that at each iteration, it amounts to the fitting of a parabola to the graph of () at the trial value , having the same slope and curvature as the graph at that point, and then proceeding to the maximum or minimum of that parabola (in higher dimensions, this may also be a saddle point), see below.
In optimization, a gradient method is an algorithm to solve problems of the form min x ∈ R n f ( x ) {\displaystyle \min _{x\in \mathbb {R} ^{n}}\;f(x)} with the search directions defined by the gradient of the function at the current point.
There, both step direction and length are computed from the gradient as the solution of a linear system of equations, with the coefficient matrix being the exact Hessian matrix (for Newton's method proper) or an estimate thereof (in the quasi-Newton methods, where the observed change in the gradient during the iterations is used to update the ...
A step of the Frank–Wolfe algorithm Initialization: Let , and let be any point in . Step 1. Direction-finding subproblem: Find solving Minimize () Subject to (Interpretation: Minimize the linear approximation of the problem given by the first-order Taylor approximation of around constrained to stay within .)
In mathematics, more specifically in numerical linear algebra, the biconjugate gradient method is an algorithm to solve systems of linear equations A x = b . {\displaystyle Ax=b.\,} Unlike the conjugate gradient method , this algorithm does not require the matrix A {\displaystyle A} to be self-adjoint , but instead one needs to perform ...
The Japanese mathematician Seki Kōwa used a form of Newton's method in the 1670s to solve single-variable equations, though the connection with calculus was missing. [6] Newton's method was first published in 1685 in A Treatise of Algebra both Historical and Practical by John Wallis. [7]