how to read previous data

Hi,

Assume that I have to use 'for loop' iterations, i = 1: n and I want to calculate a function called 'alpha' as shown below.

My problem is, how I am going to write the MATLAB code for this function especially how to extract the last 2 previous value of alpha (alpha_{i-2}?

Answer 1

[Raj]

Define alpha in an array and use the previous two elements by suitable indexing in a 'for' loop. Something like this:

n=input('Enter value of n:');
alpha=zeros(n+1,1); % Initialize alpha. Since index cannot start from zero,start from 1 upto n+1 rows
alpha(1,1)=1;
alpha(2,1)=2;
d=rand(n-1,1); % Use your d here
b=rand(n-1,1); % Use your b here
for ii=3:n+1
    alpha(ii,1)=(d(ii-2,1)*alpha(ii-1,1))-(b(ii-2,1)*alpha(ii-1,1)*alpha(ii-2,1));
end

Hope this helps!!

[Nurulhuda Ismail]

It works. Thank you very much Raj.