MATLAB: How to reduce the execution time of xcorr() function

cross correlationMATLAB

I want to find the windowed correlation values of x & y having array size of 1*20000. Xcorr function taking too much time to execute. Is there any way to reduce the execution time. The code is given below
k=1;
for i=1:stepsize:(length(x)-w+1)
    corrValue_w=xcorr(x(i:i+w-1),y(i:i+w-1));
    maxCorrValue_w(k)=max(corrValue_w);
    k=k+1;
end

Best Answer

@Jan, KSSV. Thank you so much for the solutions provided.
Solution for the problem asked is provided below;
Input matrix x & y reshaped using buffer function or bsxfun and perform the correlation at once.
% 1. Generate indexing matrix
idx = buffer(x,w,stepsize,'nodelay');
or 
idx = bsxfun( @plus, (1:w).', 0:stepsize:(numel(x)-w));
% 2. Reshape the input matrix 
x1 = x(idx); 
y1 = y(idx);
% 3. Find the correlation of each column of x1 to that of y1
corrLength=2*w - 1
xcorr_value = fftshift(ifft(fft(x1,corrLength).*conj(fft(y1,corrLength))),1); 
% 4.  Find the maximum value from each column of xcorr_value
maxCorrValue_w = max(xcorr_value,[],1);
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