Matlab摆脱循环

Question

我是Matlab的新手，并试图摆脱Java/C++习俗。
问题是“我如何摆脱这些循环。”
我试图用nchoosek（n0,2）摆脱循环的一个，但另一个问题出现了。（nchoosek的性能）

<Matlab code> 
for j=2:n0 
    for i=1:j-1 
     %wij is the number of rows of A that have 1 at both column i and column j 
     %summing col i and j to find #of common 1's 
     wij = length(find((A(:,i)+A(:,j))==2)); 
     %store it 
     W(1,j)=wij; 
     %testing whether the intersection of any two columns is too large 
     if wij>= (1+epsilon)*u2; 
     %create and edge between col i j 
     end 
    end 
end 
</matlab Code> 

Answer 1

我认为A是只有0和1的阵列。

然后，可以通过写入

B = A'*A; %'# B(i,j) = length(find((A(:,i)+A(:,j))==2)) 

%# threshold 
largeIntersection = B >= u2; 

%# find i,j of large intersections 
[largeIJ(:,1),largeIJ(:,2)] = find(largeIntersection); 

%# make sure we only get unique i,j pairs 
largeIJ = unique(sort(largeIJ,2),'rows'); 

创建colums之间的“距离” NcoI位逐NCOL阵列乙