% script file for sample example

clear;
close all;

G = numgrid('S',12);
%G = G(2:end-1,2:end-1);
A = delsq(G);
figure;
subplot(2,4,1);
spy(A);
title('Sparsity of A');
subplot(2,4,5);
L = chol(A);
spy(L');
title('Sparsity of L');

p = symrcm(A);
A1 = A(p,p);
subplot(2,4,2);
spy(A1);
title('A_1 : reordered via RCM');
L1 = chol(A1);
subplot(2,4,6);
spy(L1);
title('Sparsity of L_1 (RCM)');

p2 = mindeg(A);
A2 = A(p2,p2);
subplot(2,4,3);
spy(A2);
title('A_2 : min degree');
L2 = chol(A2);
subplot(2,4,7);
spy(L2');
title('Sparsity of L_2 (min deg)');

G = nested(12);
A3 = delsq(G);
subplot(2,4,4);
spy(A3);
title('A_3 : nested dissection');
subplot(2,4,8);
L3 = chol(A3);
spy(L3');
title('sparsity of L_3 (nested diss)');