How to write a code for an iteration?

Hi there I would like to run an iterative code.

I would like to start with a matrix f0=[a,b,c,d]

Then I would like to compute the following operation

f1=[a+b,c+d,a-b,c-d]

I would like this to be done iteratively and so that the script uses the value before.

that is f100 uses the a,b,c and value from f99.

How would I do this?

Answer 1

[Dennis]

f=zeros(100,4);
f(1,:)=[1 5 10 15];
for i=2:100
    f(i,:)=[f(i-1,1)+f(i-1,2),f(i-1,3)+f(i-1,4),f(i-1,1)-f(i-1,2),f(i-1,3)-f(i-1,4)];
end

[Victor Fletcher]

HI yes thats exactly what I was looking for.

What about if I wanted to plot a row from that resulting 100x4 matrix?

e.g. the values in the 37th row??

[Victor Fletcher]

LL=f(100,:);

%%Plot%%

figure(1)

plot(LL, 'bo-', 'LineWidth', 2);

Ahh something like this plots the values from the 100th column!!

Got itt thanks!!

Answer 2

[Torsten]

fold = [1 5 10 15];
n= 100;
for i=2:n
  f = [fold(1)+fold(2),fold(3)+fold(4),fold(1)-fold(2),fold(3)-fold(4)];
  fold = f;
end
f