# shifting of matrix elements

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sadiqa ilyas on 29 Feb 2020
Commented: sadiqa ilyas on 1 Mar 2020
hi,Can i divide the matrix into layers ,outer layer(boundary elements)then second layer and so on.
for example
original matrix is
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
25 26 27 28 29 30 31 32
33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48
49 50 51 52 53 54 55 56
57 58 59 60 61 62 63 64
After one bit right shift of outside boundary and inside layers (its like contour)
9 1 2 3 4 5 6 7
17 18 10 11 12 13 14 8
25 26 27 19 20 21 15 16
33 34 35 36 28 22 23 24
41 42 43 37 29 30 31 32
49 50 44 45 46 38 39 40
57 51 52 53 54 55 47 48
58 59 60 61 62 63 64 56

David Hill on 29 Feb 2020
Not sure if there is an easier way, but this does it for you.
function M=matShift(M)
x=size(M,1);
for k=1:floor(x/2)
z=x-2*(k-1)-1;
y=circshift([M(k,k:end-k),M(k:end-k,end-k+1)',M(end-k+1,end-k+1:-1:k+1),M(end-k+1:-1:k+1,k)'],1);
M(k,k:end-k)=y(1:z);
M(k:end-k,end-k+1)=y(z+1:2*z);
M(end-k+1,end-k+1:-1:k+1)=y(2*z+1:3*z);
M(end-k+1:-1:k+1,k)=y(3*z+1:4*z);
end

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sadiqa ilyas on 29 Feb 2020
so how to get the original matrix back
David Hill on 29 Feb 2020
Just assign to a different variable at beginning
m=M;
sadiqa ilyas on 1 Mar 2020
thanks