% MT 03 2018/19 
% Problem Set 2 Exercise 3

% 1.2
tic; 
s = 0; 
for i = 1:100000
    s = s + (1/2.^i + 1/5.^i); 
end
toc
fprintf("Sum (loop): %f \n ", s)


% 1.3 
tic; 
i=1:100000; 
su = sum(1./2.^i + 1./5.^i);
toc
fprintf("Sum (vektorized): %f \n ", su)


% 2.1 
t=0;
tic
for i=1:10000
   for j = 1:5
       H(i,j) = 1./(i+j-1);
   end
end
toc
fprintf("(Large outer loop) \n ")


t=0;
clear H
tic
for j=1:5
   for i = 1:10000
       H(i,j) = 1./(i+j-1);
   end
end
toc
fprintf("(Large inner loop) \n ")


clear H
tic
H = zeros(10000,5);
for j=1:5
   for i = 1:10000
       H(i,j) = 1./(i+j-1);
   end
end
toc
fprintf("Large inner loop, pre-allocated memory: \n ")



tic;
H = zeros(10000,5);
for j=1:5
    H2(:, j) = 1./[j:j+9999]'; 
end
toc
fprintf("(vektorized, pre-allocated memory) \n ")