Creating a loop for matrix multiplication

Hi. I am trying to create a loop to multiply two matricies 40 times such that A*B0=B1 and A*B1=B2 and so on. So far I have got this

% 
a=1-0.0277;
b=(1/15)*(1-0.008);
c=0.0215*a;
d=(14/15)*(1-0.008);
A=[[a,b];[c,d]];
B0=[6820;2140];
B=[B0];
for j=1:40
B1=A*B0;
B0=B1;
B=[B;B1];
disp(round(B(j)))
end
plot(B)

It does work but the result comes up as a list of all the values together and I want it to be a in a 1x2 matrix format.

Can anyone help? Thank you

[dpb]

How can you have a 1x2 matrix--you've got two of them which you've concatenated together vertically with the ';'. You can get a 2x2 if you simply horizontally concatenate as

B=[B B1];

but there are four elements. This is for the first pass -- after that you've got a difficulty in dimensions going forward. It's not at all clear what your end objective is, so not sure how to suggest a correction.

[Star Strider]

B actually is in an array. Changing that line to:

disp(round(B(:,j)))

will display the new columns of B as they are created.

Else, I agree.

[dpb]

@Star== Whiff... :) Edited the bonehead comment out.

[Wojtek]

Basically, this loop creates an array B which has 82 entries in one column. What I would like to have is 81 separate arrays created using elements of B.

So for example C1=B(1:2,1), C2=B(3:4,1) and so on.

I have tried to write something like this:

for k=1:41
  for a=1:2:81
     for b=2:2:82
       C(k)=B(a:b,1)
       disp(C)
     end
  end
 end

But that doesn't work.

[John D'Errico]

NO NO NO NO. Do not create 81 different named variables. Learn to use arrays of variables. Your code will be the better for it. Your mental health a bit better too, because your code will not drive you crazy.

Answer 1

[Wojtek]

Problem solved. I have used this

x=length(B);
y=x/2;
C=[];
for i=1:41
  C=[C B(2*i-1:2*i)];
end

Thank you all for your comments.

[Jos (10584)]

for i=1:41,
   C = [C B(2*i-1:2*i)]
end

is exactly the same as

C = B(1:82)