La factorisation de Cholesky, également connue sous le nom de Cholesky Décomposition, is a mathematical technique used in algèbre linéaire to factorize a positive-definite matrix into a product of a lower triangular matrix and its transpose. This factorization is particularly useful in various applications, including solving systems of linear equations, optimization problems, and in méthodes statistiques.
Plus précisément, si A is a symmetric, positive-definite matrix, the Cholesky Factorization states that there exists a unique lower triangular matrix L tel que :
A = L * L^TT
where LT is the transpose of L. The process of obtaining L involves a series of calculations that eliminate variables step by step, ensuring that the resulting matrix is triangular.
Cholesky Factorization is computationally efficient, requiring approximately half the number of operations needed for other factorization methods such as LU decomposition. Its advantages make it favorable in algorithms requiring matrix inversion or solving linear systems, especially in the context of machine learning and numerical simulations. Additionally, it plays a critical role in Monte Carlo methods and les algorithmes d'optimisation, where the efficiency of matrix computations is crucial.
En résumé, la factorisation de Cholesky est un outil puissant en algèbre linéaire numérique, providing a means to simplify complex calculations involving positive-definite matrices.