Vectorization of multiple embedded for loops

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I have the following code that includes 3 iterated for loops in order to create an upper diagonal matrix, I plan on performing on large data set many times and want to make as computationally efficient as possible.
data = magic(3);
n = size(data,1);
W = zeros(n,n);
for i = 1:n
for j = i:n
if i==j
www(i,j)=0;
else
for k = 1:n
temp(1,k) = (data(i,k)-data(j,k))^2;
sumTemp = sumTemp + temp(1,k);
end
W(i,j)=sqrt(sumTemp);
end
temp = 0;
sumTemp = 0;
end
end
Answer should look like:
[0 6.4807 9.7980
0 0 6.4807
0 0 0]
I am working it hard right now, but figure I would throw it out there in case anyone has any suggestions that would save me hours of fiddling around. Thanks in advance.
Keith

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 24 Oct 2013
W = triu(squeeze(sqrt(sum(bsxfun(@minus,data,permute(data,[3 2 1])).^2,2))));
  2 Comments
Keith
Keith on 24 Oct 2013
Edited: Keith on 24 Oct 2013
Andrei - quite impressive. I would like to get to the point where I can vectorize like this. Can you point me to any good learning references. Thanks for quick and accurate response!
Andrei Bobrov
Andrei Bobrov on 25 Oct 2013
Hi Keith! Full vectoring is not always the best solution. About efficient training: I think, this site and documentation for MATLAB.

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