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  2. Matrix-free methods - Wikipedia

    en.wikipedia.org/wiki/Matrix-free_methods

    In computational mathematics, a matrix-free method is an algorithm for solving a linear system of equations or an eigenvalue problem that does not store the coefficient matrix explicitly, but accesses the matrix by evaluating matrix-vector products. [1] Such methods can be preferable when the matrix is so big that storing and manipulating it ...

  3. LOBPCG - Wikipedia

    en.wikipedia.org/wiki/LOBPCG

    Kantorovich in 1948 proposed calculating the smallest eigenvalue of a symmetric matrix by steepest descent using a direction = of a scaled gradient of a Rayleigh quotient = (,) / (,) in a scalar product (,) = ′, with the step size computed by minimizing the Rayleigh quotient in the linear span of the vectors and , i.e. in a locally optimal manner.

  4. Inverse iteration - Wikipedia

    en.wikipedia.org/wiki/Inverse_iteration

    In numerical analysis, inverse iteration (also known as the inverse power method) is an iterative eigenvalue algorithm. It allows one to find an approximate eigenvector when an approximation to a corresponding eigenvalue is already known. The method is conceptually similar to the power method. It appears to have originally been developed to ...

  5. Eigenvalue algorithm - Wikipedia

    en.wikipedia.org/wiki/Eigenvalue_algorithm

    Given an n × n square matrix A of real or complex numbers, an eigenvalue λ and its associated generalized eigenvector v are a pair obeying the relation [1] =,where v is a nonzero n × 1 column vector, I is the n × n identity matrix, k is a positive integer, and both λ and v are allowed to be complex even when A is real.l When k = 1, the vector is called simply an eigenvector, and the pair ...

  6. Tridiagonal matrix algorithm - Wikipedia

    en.wikipedia.org/wiki/Tridiagonal_matrix_algorithm

    Indeed, multiplying each equation of the second auxiliary system by , adding with the corresponding equation of the first auxiliary system and using the representation = +, we immediately see that equations number 2 through n of the original system are satisfied; it only remains to satisfy equation number 1.

  7. Radial distribution function - Wikipedia

    en.wikipedia.org/wiki/Radial_distribution_function

    Given a potential energy function, the radial distribution function can be computed either via computer simulation methods like the Monte Carlo method, or via the Ornstein–Zernike equation, using approximative closure relations like the Percus–Yevick approximation or the hypernetted-chain theory. It can also be determined experimentally, by ...

  8. Conjugate gradient squared method - Wikipedia

    en.wikipedia.org/wiki/Conjugate_gradient_squared...

    A system of linear equations = consists of a known matrix and a known vector. To solve the system is to find the value of the unknown vector x {\displaystyle {\mathbf {x}}} . [ 3 ] [ 5 ] A direct method for solving a system of linear equations is to take the inverse of the matrix A {\displaystyle A} , then calculate x = A − 1 b {\displaystyle ...

  9. Gram–Schmidt process - Wikipedia

    en.wikipedia.org/wiki/Gram–Schmidt_process

    The first two steps of the Gram–Schmidt process. In mathematics, particularly linear algebra and numerical analysis, the Gram–Schmidt process or Gram-Schmidt algorithm is a way of finding a set of two or more vectors that are perpendicular to each other.