correlation example

func = @(x) tri(x).*ustep(x);
x = linspace(-2,2,401);
dx = x(2)-x(1);
y = func(x);
y1 = convn(y,y,'same')*dx;
y2 = convn(y,func(-x),'same')*dx;
subplot(3,1,1);
plot(x,y,'LineWidth',1.5);
grid;
ylabel('f(x)');
subplot(3,1,2);
plot(x,y1,'LineWidth',1.5);
grid;
ylabel('convolve(f,f)');
subplot(3,1,3);
plot(x,y2,'Linewidth',1.5);
grid;
ylabel('correlate(f,f)');