Broyden–Fletcher–Goldfarb–Shanno algorithm

The Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm is an iterative method for solving unconstrained nonlinear optimization problems. It is part of a broader class of algorithms known as quasi-Newton methods, which are used to find local minima of differentiable functions. The key idea behind quasi-Newton methods is to use an approximation to the Hessian matrix (the matrix of second derivatives of the objective function) to facilitate efficient optimization.