Optimization of a nested loop

2012 6 22
2 个回答
12 次查看（30 天）

0 个投票

Hello guys I wrote the following code, but it takes ages to complete. Could you please help me optimizing it? A and B are matrixes
for i=1:length(A)
for j=1:length(B)
CCI = CCI + heaviside(norm(A(i,:)-B(j,:)));
end
end
Thanks

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回答（2 个）

Sean de Wolski
Sean de Wolski 2012-6-22

0 个投票

Not necessarily faster, prettier, less confusing or better in any way with the exception of being on one line and containing the awesomeness that is bsxfun:
CCI2 = sum(sum(heaviside(sqrt(sum(bsxfun(@minus,A,reshape(B',1,size(B,2),size(B,1))).^2,2)))))
Andrei Bobrov
Andrei Bobrov 2012-6-22

0 个投票

other variant
CCI = (nnz(any(bsxfun(@minus,A,reshape(B',1,size(B,2),[])),2)) + size(A,1)*size(B,1))/2;

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Italo
Italo
2012-6-22

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