How can Overlap-add technique be done

Hi:), I would like to perform the overlap-add technique but it seems to have errors. any ideas

load handel

N=length(y);

L=8192;

b=[0.2];

a=[1 -0.8];

[hn,t]=impz(b,a);

M=length(hn);

 Nx=floor((N+M-1-1))/(L)
   H = fft(hn,N)     %% (zero-padded FFT)
   i = 1

   while i <= Nx
       il = min(i+L-1,Nx)
       wt = ifft( fft(y(i:il),N) .* H, N);
       k  = min(i+N-1,Nx);
       w(i:k) = w(i:k) + wt ;   %%(add the overlapped output blocks)
       i = i+L;
   end

[Walter Roberson]

What errors do you perceive?

Note: you might want to consider using "for" instead of "while"

[Ijeoma Madu]

Thanks Walter. i get this error and not so sure what this means

Undefined function or method 'w' for input arguments of type 'double'.

Error in ==> asp2 at 20 w(i:k) = w(i:k) + wt ; %%(add the overlapped output blocks)

Answer 1

[Walter Roberson]

Initialize your matrix w, with

w = zeros(1,Nx);

before you start the loop.

[Ijeoma Madu]

Thanks