how to convert a given matrix in an array while reading all the elements of matrix in a particular order.

I want to write a program in matlab to convert a matrix into an array. the values of the matrix should be read diagionally starting from any one element of the matrix then forming a continuous loop till end

For example;

let's assume the matrix

 [1  2  3  4  5  6;
 7  8  9 10 11 12;
 13 14 15 16 17 18;
 19 20 21 22 23 24]

the matrix converted into an array by reading the elements diagonally like

1 7 2 3 8 13 19 14 9 4 5 10 15 20 21 16 11 6 12 17 22 23 18 24

Please help!!

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/15317-zigzag-scan

[Neetika Bhalla]

Thanks for the reply. In this program the scan start from the first element of the matrix ...can we start the scan from any other element of a matrix..and then follow the same zig zag pattern covering all the elements of matrix

[Walter Roberson]

circshift() the result of the zigzag that starts from the beginning.

[ramakrishn palnati]

how to retrieve original matrix from zigzag. please send me

Answer 2

[Azzi Abdelmalek]

A=[1 2 3 4 5 6; 7 8 9 10 11 12; 13 14 15 16 17 18; 19 20 21 22 23 24]   
q=spdiags(rot90(A))
q(:,2:2:end)=flipud(q(:,2:2:end))
out=nonzeros(q(:))'

[Andrei Bobrov]

+1

Answer 3

[Andrei Bobrov]

Variant by Azzi with the small addition:

A = randi([-6 6],4,6);

ii =  reshape(1:numel(A),size(A));
z = spdiags(ii(end:-1:1,:));
z(:,1:2:end) = z(end:-1:1,1:2:end);
out = A(z(z~=0))';