% Script diagdom.m
% diagonally dominant matrices:  examples
format short

A = [3 1 1; 1 3 1; 1 1 3]
[L,U,P] = lu(A)   % P is eye(3), the identity matrix; no row switch

% 
B = [4 2 1 0; 1 4 1 1; 1 0 5 3; 0 0 4 6]
[L,U,P] = lu(B)   % P is eye(4)

% add your own example

% try a case when the sum of the nondiagonal
% elements in each row equals the absolute value of the diagonal term

D = [ 4 2 1 1; 2 4 1 1; 1 2 4 1; 1 1 2 4]
[L,U,P] = lu(D)