Representation of matrix in term of sets

Code:

n=3
A = eye(n); 
idx = randperm(n);
A = A(idx, :)
for i=1:n
    for j=1:n
        if  A(i,j)~=0 && A(i,i)~=1
            k1=[i j]
            
        end
    end
end

Output:

I have attached pdf below please find the attachment.

Here I got, k1= 1 2 and k1=2 1

But I want

In set form

But I am getting in matrix form.

How to proceed please give me guideline.

Thanks in advance.

Answer 1

[Matt J]

Simpler:

d=diag(A);
A(d==1,:)=0;

[I,J]=find(A);

k=[I,J];

I don't know what you mean by "set form". If you want each pair as the element of cell array, simply do

k=num2cell(k,2)

[Matt J]

rohini's comment moved here:

Firstly I would like to say Thank you for your valuable suggestion .

As per your suggestion I got result which is mentioned in pdf

but here I am getting k in cell format

but I want

i.e. representation should be in set .

Please give me guideline in this direction.

Thanks in advance.

[Matt J]

What is the difference between cell format and "set representation"?

[rohini more]

Obviously there is no difference between result.

But I want set representation because in the similar manner I want to creat another set let say k2

then I want to check that whether k or(k1) is a subset of k2 or not.

Thank you for your reply.

[Matt J]

For things like that, it is best to have k as an Nx2 matrix (the original form I give you). If k1 and k2 are both in this form, you can determine whether k1 is a subset of k2 with,

all(ismember(k1,k2,'rows'))

Matlab does not have a "set" data type like Python, if that's what you were hoping.

[rohini more]

Okay.

Thank you for your suggestion.

Really thanks a lot for your valuable time.

[rohini more]

After applying below command I am getting error which is mentioned in the pdf. Please find the attachment

all(ismember(k1,k2,'rows'))

Please give me suggestion to get rid of this error

Thanks a lot for investing your valuable time on this query and also for valuable suggestion.