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  2. Hessian matrix - Wikipedia

    en.wikipedia.org/wiki/Hessian_matrix

    The Hessian matrix plays an important role in Morse theory and catastrophe theory, because its kernel and eigenvalues allow classification of the critical points. [2] [3] [4] The determinant of the Hessian matrix, when evaluated at a critical point of a function, is equal to the Gaussian curvature of the function considered as a manifold. The ...

  3. Symmetry of second derivatives - Wikipedia

    en.wikipedia.org/wiki/Symmetry_of_second_derivatives

    In other words, the matrix of the second-order partial derivatives, known as the Hessian matrix, is a symmetric matrix. Sufficient conditions for the symmetry to hold are given by Schwarz's theorem, also called Clairaut's theorem or Young's theorem. [1] [2]

  4. Ridge detection - Wikipedia

    en.wikipedia.org/wiki/Ridge_detection

    Ridge detection has also been furthered by Lindeberg with the introduction of -normalized derivatives and scale-space ridges defined from local maximization of the appropriately normalized main principal curvature of the Hessian matrix (or other measures of ridge strength) over space and over scale.

  5. Limited-memory BFGS - Wikipedia

    en.wikipedia.org/wiki/Limited-memory_BFGS

    An alternative approach is the compact representation, which involves a low-rank representation for the direct and/or inverse Hessian. [6] This represents the Hessian as a sum of a diagonal matrix and a low-rank update. Such a representation enables the use of L-BFGS in constrained settings, for example, as part of the SQP method.

  6. Second partial derivative test - Wikipedia

    en.wikipedia.org/wiki/Second_partial_derivative_test

    The following test can be applied at any critical point a for which the Hessian matrix is invertible: If the Hessian is positive definite (equivalently, has all eigenvalues positive) at a, then f attains a local minimum at a. If the Hessian is negative definite (equivalently, has all eigenvalues negative) at a, then f attains a local maximum at a.

  7. Broyden–Fletcher–Goldfarb–Shanno algorithm - Wikipedia

    en.wikipedia.org/wiki/Broyden–Fletcher...

    Therefore, in order to avoid any matrix inversion, the inverse of the Hessian can be approximated instead of the Hessian itself: =. [9] From an initial guess x 0 {\displaystyle \mathbf {x} _{0}} and an approximate inverted Hessian matrix H 0 {\displaystyle H_{0}} the following steps are repeated as x k {\displaystyle \mathbf {x} _{k}} converges ...

  8. Hessian equation - Wikipedia

    en.wikipedia.org/wiki/Hessian_equation

    In mathematics, k-Hessian equations (or Hessian equations for short) are partial differential equations (PDEs) based on the Hessian matrix. More specifically, a Hessian equation is the k-trace, or the kth elementary symmetric polynomial of eigenvalues of the Hessian matrix. When k ≥ 2, the k-Hessian equation is a fully nonlinear partial ...

  9. Non-linear least squares - Wikipedia

    en.wikipedia.org/wiki/Non-linear_least_squares

    The matrix H is known as the Hessian matrix. Although this model has better convergence properties near to the minimum, it is much worse when the parameters are far from their optimal values. Calculation of the Hessian adds to the complexity of the algorithm. This method is not in general use. Davidon–Fletcher–Powell method. This method, a ...