how to create adjacency matrix

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chan
chan on 3 Oct 2015
Commented: Walter Roberson on 4 Oct 2015
How to create adjacency matrix 10 by 10 based on this developed commands
X=randi([1,1000],10,1); M=[X,X(randperm(length(X)))];
Whenever there is a common value in the matrix developed assign 1 in the matrix 10 by 10 else 0. (using for loop)
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chan
chan on 4 Oct 2015
NO sir your code din't work.i have attached a file.the output will be like that based on that M matrix.In first row there are two 1's because node 1 is sharing key with 7 and 8.similarly i have to find for other nodes with whom they are sharing key.Sir could you please help in implementing this using for loop.thank you.
Walter Roberson
Walter Roberson on 4 Oct 2015
You did not attach a file.
When you used randperm() like that, each element will appear exactly once, and so node 1 should share "keys" with only one other node.
Read the adjacency matrix I created down the rows. Or reverse the order of the indices. Makes no difference to me.

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Answers (1)

Walter Roberson
Walter Roberson on 3 Oct 2015
My guess as to what you want is:
X = randi([1,1000],10,1);
idx = [(1:length(X)).', randperm(length(X)).'];
M = X(idx);
Adj = zeros(length(X),length(X));
Adj(sub2ind(size(Adj), idx(:,1), idx(:,2))) = 1;
That last line can be more efficiently written as
Adj(length(X)*(idx(:,2)-1)+idx(:,1)) = 1;

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