Help with creating a function which is dependent on the array previous values

Hello,

I need to create a first order or a second order Predictar and the user get to decide which order he wants. And the predictator is basically a new utlaized array of the main one but with its values dependent on the previous values ( first order depends on only 1 previous value, while 2nd order depends on 2 previous values and so on)

Here is how I did the first order Predictaror

%% x_k is my message signal

x_kdelay = [0 x_k(1:end-1)]; %Delay by 1 unit

d_k = x_k - x_kdelay;

But then I wanted to add the second order and here is what I did, but it's giving me an error.

x_kdelay = [0 x_k(1:end-1)]; %Delay by 1 unit

%%%%% Predictator (New global state)

if p == 1

d_k = x_k - x_kdelay;

elseif p == 2

for i5= 1: numel(x_k)

d_k(i5) = x_k(i5) - (x_kdelay(i)+x_kdelay(i-1))

end

end

Then Later on I want to re-do this step at the receiver side, here is the function I created for the first order Predictator re-do.

intial = 0;

x_hat = [];

for i3 = 1:numel(d_k)

x_ind = intial +dq_tx(i3);

x_hat = [x_hat x_ind];

intial = x_ind;

end

And I would apprechiate any help in modifying it to support the second order case as well.

Thank you

[Dyuman Joshi]

In the if-else segment, the loop index is incorrect or the variable i is not defined .

If it is i5, and since i5 starts with 1, then i5-1 == 0 will give you an error when used as an index.

if p == 1
    d_k = x_k - x_kdelay;
elseif p == 2
    for i5= 1: numel(x_k)
        d_k(i5) = x_k(i5) - (x_kdelay(i)+x_kdelay(i-1))
                                     %^          %^
    end  
end

For the 2nd code snippet, x_hat is same as cumsum(dq_tx(1:numel(d_k)) and initial is equalto last value of x_hat.

[Abdelrhman Abdelfatah]

ohh yess, thank you so much, would work on it.