Is it possible to remove this for loop to speed up the processing?

I have following loop in my codes:

for n=1:Na
   sig1(n,m) = sig(n,m+RCM(n));
end

where Na is a large number,28001;

the row number of sig1 and sig are the same;

the column of sig is larger than that of sig1;

RCM is a Nax1 vector.

Thanks in advance.

[Stephen23]

This task is trivial to perform with MATLAB's very simple but powerful indexing:

http://www.mathworks.com/help/matlab/math/matrix-indexing.html

http://www.mathworks.com/help/matlab/learn_matlab/array-indexing.html

http://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html

[feng hongchuan]

Thanks.

Answer 1

[Walter Roberson]

N = 1 : Na;
sR = size(sig,1);
sig1((m-1)*sR + N) = sig((m+RCM-1)*sR + N);

No looping.

The above code uses linear indexing and uses knowledge of how to convert 2D indices into linear indices.

[feng hongchuan]

Very helpful. Thank you so much!