column circular permutaion on a matrix

How can I move all the elements of a particular column circulary upwards or circularly downwards by some shift s. I have a matrix A = [ 1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16] and shift columns 1, 2, 3 and 4 by shifts 2, 1 , 3 and 2 respectively then I get the matrix A as A = [9 6 15 12; 13 10 3 16; 1 14 7 4; 5 2 11 8].

Answer 1

[Ameer Hamza]

Try this

A = [ 1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16];
B = [9 6 15 12; 13 10 3 16; 1 14 7 4; 5 2 11 8];
shift = [2, 1, 3, 2];

C = A; % make a copy
for i=1:numel(shift)
    C(:,i) = circshift(C(:,i), -shift(i));
end

Result

>> isequal(B, C)
ans =
  logical
   1

[Abhishek Bakhla]

thank you.

[Ameer Hamza]

Glad to be of help.

Answer 2

[Ilian]

If you just want to rotate the rows this could work:

s = -3; % shift (both positive and negative values work)
rows = size(A,1);
B = [A(mod(s-rows,rows)+1:end,:); A(1:mod(s-rows,rows),:)];

[Abhishek Bakhla]

thank you.

Answer 3

[Stephen23]

No loops:

>> A = [1,2,3,4;5,6,7,8;9,10,11,12;13,14,15,16];
>> S = [2,1,3,2]; % shifts
>> [R,C] = ndgrid(1:4,1:4);
>> B = A(sub2ind([4,4],1+mod(S+R-1,4),C))
B =
    9    6   15   12
   13   10    3   16
    1   14    7    4
    5    2   11    8

[Abhishek Bakhla]

thank you.