How to replace the diagonal elements of a matrix with 0 fro avoiding self loops?

I have a matrix

 M= 1 0 0 0 1 0
    0 1 0 1 0 0
    0 0 1 0 1 1
    1 0 0 1 0 0
    1 1 1 0 0 0
    0 0 0 1 0 1
I want to replace all the diagonal elements in this matrix to 0 if it is 1.

[Ramtin Nazerian]

Out = M.*-(eye(height(M))-1);

This will make all the diagonal values of your matrix zero as long as the matrix is square. hope that helps :).

Answer 1

[Andrei Bobrov]

out = M - diag(diag(M));

[Michael Chan]

Not working if the diagonal is Inf or nan

[tommsch]

Also not working, if the matrix is not square

Answer 2

[Stephen23]

Method one: indexing:

M(1:1+size(M,1):end) = 0

Method two: eye:

M.*~eye(size(M))

[Stephen23]

A strict interpretation of the question requires only diagonals equal to one get changed to zero: this is easy to implement with eye:

M.*~(eye(size(M)) & M==1)

Answer 3

[Roger Stafford]

If your matrix M is not square and if you only want those diagonal elements changed to zero “if it is 1”, then you can do the following. Other diagonal elements not equal to one will remain unchanged. (Your description was perhaps a little ambiguous on this latter point.)

   [m,n] = size(M);
   d = 1:m+1:min(m^2,m*(n-1)+m);
   f = find(M(d))==1;
   M(d(f)) = 0;

[Bruno Luong]

Sorry to others, but this is the only right answer to the question.

[Hans Jakob Rivertz]

This does the same in one line.

M = M-diag(diag(M==1))

[Stephen23]

@Hans Jakob Rivertz: not once you consider non-square matrices.

[Zeina Abdullah]

@Stephen can you help me by try to answer the last question in my profile please

Answer 4

[Christine Tobler]

If you are using the graph/digraph classes, you can also tell the constructor not to insert any self-loops for the diagonal elements:

 g = graph(A, 'omitSelfLoops');