% 
% Written by:
% -- 
% John L. Weatherwax                2006-12-31
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

close all; 

% Part (a):
%
E = 5; 
S  = linspace(E-20,E+20)'; 
PI = -S + 2*max([S-E,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (a)'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_a.eps' ); 

pause; close all; 

% Part (b):
%
E = 5; 
S  = linspace(E-20,E+20)'; 
PI = max([S-E,zeros(size(S))],[],2) + max([E-S,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' );
axis( [ -15 +25 -7.5 40 ] );  
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (b)'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_b.eps' ); 

pause; close all; 

% Part (c):
%
E = 5; 
S  = linspace(E-20,E+20)'; 
PI = max([S-E,zeros(size(S))],[],2) + 2*max([E-S,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (c)'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_c.eps' ); 

pause; close all; 

% Part (d):
%
E = 5; 
S  = linspace(E-20,E+20)'; 
PI = max([E-S,zeros(size(S))],[],2) + 2*max([S-E,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (d)'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_d.eps' ); 

pause; close all; 

% Part (e) part 1:
%
E1 = 15; E2 = 10;
S  = linspace(E-20,E+20)'; 
PI = max([S-E1,zeros(size(S))],[],2) + max([E2-S,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (e) part 1'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_e_pt1.eps' ); 

% Part (e) part 2:
% 
E1 = 5; E2 = E1;
S  = linspace(E-20,E+20)'; 
PI = max([S-E1,zeros(size(S))],[],2) + max([E2-S,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (e) part 2'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_e_pt2.eps' ); 

% Part (e) part 3:
% 
E1 = 5; E2 = 10;
S  = linspace(E-20,E+20)'; 
PI = max([S-E1,zeros(size(S))],[],2) + max([E2-S,zeros(size(S))],[],2);
figure; plot( S, PI, 'o' ); 
axis( [ -15 +25 -7.5 40 ] ); 
xlabel('stock price at expiry'); ylabel('portfolio profit'); 
title('Part (e) part 3'); 
%saveas( gcf, '../WriteUp/Graphics/prob_3_2_e_pt3.eps' );