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In numerical linear algebra, the Gauss–Seidel method, also known as the Liebmann method or the method of successive displacement, is an iterative method used to solve a linear system of equations. It is named after the German mathematicians Carl Friedrich Gauss and Philipp Ludwig von Seidel, and is similar to the Jacobi method. Though it can be applied to any matrix with non-zero elements on the diagonals, convergence is only guaranteed if the matrix is either diagonally dominant, or symmetric and positive definite. It was only mentioned in a private letter from Gauss to his student Gerling in 1823.〔 ; (direct link ).〕 A publication was not delivered before 1874 by Seidel. == Description == The Gauss–Seidel method is an iterative technique for solving a square system of ''n'' linear equations with unknown x: :. It is defined by the iteration : where is the ''k''th approximation or iteration of is the next or ''k'' + 1 iteration of , and the matrix ''A'' is decomposed into a lower triangular component , and a strictly upper triangular component ''U'': .〔.〕 In more detail, write out ''A'', x and b in their components: : Then the decomposition of ''A'' into its lower triangular component and its strictly upper triangular component is given by: : The system of linear equations may be rewritten as: : The Gauss–Seidel method now solves the left hand side of this expression for x, using previous value for x on the right hand side. Analytically, this may be written as: : However, by taking advantage of the triangular form of , the elements of x(''k''+1) can be computed sequentially using forward substitution: : 〔.〕 The procedure is generally continued until the changes made by an iteration are below some tolerance, such as a sufficiently small residual. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Gauss–Seidel method」の詳細全文を読む スポンサード リンク
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