Creating a loop for matrix multiplication

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Wojtek
Wojtek 2014-5-11
评论： Jos (10584) 2014-5-13
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
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Wojtek
Wojtek 2014-5-12
编辑：Wojtek 2014-5-12
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
John D'Errico 2014-5-12
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.

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回答（1 个）

Wojtek
Wojtek 2014-5-13
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.

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