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.
% Copyright 2012 Cleve Moler and The MathWorks, Inc.
s = 10;
L = tril(round(s*randn(n)),-1)+eye(n);
U = triu(round(s*randn(n)),1)+eye(n);
A = L*U;