Delete value in matrix at crescent way and rearrange

Hello everyone and thanks for the help.

I'm working with a 1000x1000 matrix, example:

I want to delete the last value of the last row, and the two last values of the penultimate line, and so go on, like this:

After this I want to bring the last value to the end of the matrix:

And delete the column in the left (cause I bring the lat value of the raw to the right I would get: 1 columns delete for the last raw, 2 columns delete for the penultimate raw, so go on) . So if a did this with the last 500 rows. I would get a 500x500 matrix. Someone have a though about how to begging this script?

Short example: 8x8

...

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

Response: 4x4

..

1 2 3 4

2 3 4 5

2 3 4 5

4 5 6 7

Answer 1

[Ameer Hamza]

For you short example:

x = [1:8; 1:8; 1:8; 1:8];
n = 4;
new_x = zeros(n);
for i=1:4
    new_x(:,i) = diag(x, i-1);
end

Result:

new_x =
     1     2     3     4
     2     3     4     5
     3     4     5     6
     4     5     6     7

[Richard Perosa Fernandes]

Thank you very much. Works just fine!

[Ameer Hamza]

Glad to be of help.