find cycle in array
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I have a M M=[1,2 ;1,5; 2,4;2,5;4,5; 4,9;5,6;6,11;9,10;10,11] I want to find a loop in this array. I want this answer A={[1,2,5],[2,4,5],[4,5,6,9,10,11]}
7 个评论
Guillaume
2018-10-22
I'm assuming that your M represents the edges of a graph. Don't you think it's essential information that you should have mentioned?
You can plot your graph with:
M = [1,2 ;1,5; 2,4;2,5;4,5; 4,9;5,6;6,11;9,10;10,11]
G = graph(M(:, 1), M(:, 2));
plot(G)
which outputs
Why are loops
[1 2 4 5]
[2 5 6 11 10 9 4]
etc.
not valid outputs?
Guillaume
2018-10-22
Yes, but [1 2 4 5] is also a loop. So is [1 2 4 9 10 11 6 5]. Why are these not included in your list?
Sim
2019-10-7
Hi Naime! I have your exact problem... Did you find any solution to share ?
Yes, thank you.. I tried what you suggested:
[1] Count all cycles in simple undirected graph version 1.2.0.0 (5.43 KB) by Jeff Howbert
[2] Count Loops in a Graph version 1.1.0.0 (167 KB) by Joseph Kirk
Unfortunately, both solutions [1] and [2] were not working for my case... but I understood more about the problem and the way to describe it! Thanks a lot, very helpful FileExchange submissions!
Just for information, the solution I was looking for was kindly provided by Matt J here:
Can Chen
2020-6-5
Hi Na, I work at MathWorks on graphs. If you have a few minutes, I would very much appreciate hearing more about your workflow using cycles. Would you please contact me directly?
采纳的回答
This can be done using the spatialgraph2D submission on the File Exchange,
M = [1,2 ;1,5; 2,4;2,5;4,5; 4,9;5,6;6,11;9,10;10,11]
G = graph(M(:, 1), M(:, 2));
hg=plot(G);
obj=spatialgraph2D(G,hg.XData,hg.YData);
[~,A]=obj.polyshape;
>> A{:}
ans =
1 5 2
ans =
2 5 4
ans =
4 5 6 11 10 9
>> obj.mosaic
更多回答（2 个）
KSSV
2018-10-22
M=[1,2 ;1,5; 2,4;2,5;4,5; 4,9;5,6;6,11;9,10;10,11] ;
A={[1,2,5],[2,4,5],[4,5,6,9,10,11]} ;
[c,ia,ib] = unique(M(:,1)) ;
N = length(c) ;
B = cell(N,1) ;
for i = 1:length(c)
T = M(ib==i,:) ;
B{i} = unique(T(:)) ;
end
Guillaume
2018-10-22
0 个投票
There are no built-in algorithms in matlab to find cycles in graphs (undirected or directed). You'll either have to write your own, eg. using DFS or BFS (both DFS and BFS are implemented in matlab) or some other algorithm that you can find using your favorite search engine, or you'll have to use one of the submissions in the FileExchange ( [1], [2], and probably more)
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在 帮助中心 和 File Exchange 中查找有关 Undirected Graphs 的更多信息
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