www.pudn.com > NumericalComputing.rar > golub.m, change:2003-10-23,size:434b

function A = golub(n) %GOLUB Badly conditioned integer test matrices. % GOLUB(n) is the product of two random integer n-by-n matrices, % one of them unit lower triangular and one unit upper triangular. % LU factorization without pivoting fails to reveal that such % matrices are badly conditioned. % See also LUGUI. s = 10; L = tril(round(s*randn(n)),-1)+eye(n); U = triu(round(s*randn(n)),1)+eye(n); A = L*U;