% Generates Figure 7.2

session_p148

x = zeros(size(b));
perm = symmmd(A);            % minimal degree ordering
R = chol(A(perm,perm));
x(perm,:) = R\(R'\b(perm,:));

subplot(1,2,1), spy(A(perm,perm)); 
subplot(1,2,2), spy(R');
