% CAAM 454 - Homework 8 test8a script

func = @rosenbrock_g;
n = input('n = ');
tol = 1.e-12;  maxit = 300;
x01 = 1.2*ones(n,1); 
x02 = x01;
x02(1:2:n-1) = -1.2;
x02(2:2:n) = 1;

if exist('zBFGS'); t0 = cputime; 
[x,sflag,hist] = zBFGS(func,x01,tol,maxit);
fh1 = hist(1,:); gh1 = hist(2,:);
[x,sflag,hist] = zBFGS(func,x02,tol,maxit);
fh2 = hist(1,:); gh2 = hist(2,:);
fprintf('zBFGS: total CPU = %8.4e\n\n',cputime-t0);
figure(1);
subplot(221); semilogy(1:length(fh1),fh1,'b-*');
xlabel('Iteration vs. f'); ylabel('func')
title('zBFGS, x0 = (1.2, 1.2)');
subplot(223); semilogy(1:length(gh1),gh1,'b-*');
xlabel('Iteration vs. g'); ylabel('||g||_2')
title('zBFGS, x0 = (1.2, 1.2)');
subplot(222); semilogy(1:length(fh2),fh2,'b-*');
xlabel('Iteration'); ylabel('func')
title('zBFGS, x0 = (-1.2, 1.0)');
subplot(224); semilogy(1:length(gh2),gh2,'b-*');
xlabel('Iteration'); ylabel('||g||_2')
title('zBFGS, x0 = (-1.2, 1.0)');
end;

if exist('myBFGS'); t0 = cputime;
[x,sflag,hist] = myBFGS(func,x01,tol,maxit);
fh1 = hist(1,:); gh1 = hist(2,:);
[x,sflag,hist] = myBFGS(func,x02,tol,maxit);
fh2 = hist(1,:); gh2 = hist(2,:);
fprintf('myBFGS: total CPU = %8.4e\n\n',cputime-t0);
figure(2);
subplot(221); semilogy(1:length(fh1),fh1,'r-*');
xlabel('Iteration vs. f'); ylabel('func')
title('myBFGS, x0 = (1.2, 1.2)');
subplot(223); semilogy(1:length(gh1),gh1,'r-*');
xlabel('Iteration vs. g'); ylabel('||g||_2')
title('myBFGS, x0 = (1.2, 1.2)');
subplot(222); semilogy(1:length(fh2),fh2,'r-*');
xlabel('Iteration'); ylabel('func')
title('myBFGS, x0 = (-1.2, 1.0)');
subplot(224); semilogy(1:length(gh2),gh2,'r-*');
xlabel('Iteration'); ylabel('||g||_2')
title('myBFGS, x0 = (-1.2, 1.0)');
end;