www.pudn.com > NumericalComputingwithMatlabCode.zip > 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;