(Anti)diagonal automation

Counting from the top right element to the the bottom left element of an indicative 5x5 matrix, is there a quick way to automate the simulation of all the antidiagonals?

a(1,1) =1
  a(2,1) =2
  a(1,2) =2
  a(3,1)= 3
  a(2,2)=3
  a(1,3)=3
  a(4,1)=4
  a(2,3)=4
  a(3,2)=4
  a(1,4)=4
  a(1,5)=5
  a(4,2)=5
  a(3,3)=5
  a(2,4)=5
  a(5,1)=5
  a(5,5)=1

[John D'Errico]

What does it mean to "simulate" the anti-diagonals?

Are you asking how to create that array?

It is not clear what your goal is, since you do not seem to be doing something consistent along all the anti-diagonals.

[GEORGIOS BEKAS]

antidiagonal: All elements from the top right element to the the bottom left element. The code describes 5 of them for an indicative 5x5 matrix.

[John D'Errico]

Sigh. I know what an anti-diagonal is.

What you have not said is what is your goal. You filled only the first 5 anti-diagonals. Then you stuffed the (5,5) element with a 1. So what are you looking to get? Why did you not fill the other ant-diagonals? How do we know what you are looking for here?

Finally, what does it mean to SIMULATE anti-diagonal?

[GEORGIOS BEKAS]

how can I take the elements of all antidiagonals from any matrix?

Answer 1

[Steven Lord]

Flip the matrix using the flip function then call diag.

[GEORGIOS BEKAS]

I am searching for a code to use it for the other (smaller) anti-diagonals as well.

[Roger Stafford]

The second argument in the 'diag' function provides for the smaller diagonals, which "flipped" would be the smaller anti-diagonals.

[Kaouthar Bouyaouzan]

@Steven Lord Thank you !