time   calls  line
                  1 function B = rot90(A,k)
                  2 %ROT90  Rotate matrix 90 degrees.
                  3 %   ROT90(A) is the 90 degree counterclockwise rotation of matrix A.
                  4 %   ROT90(A,K) is the K*90 degree rotation of A, K = +-1,+-2,...
                  5 %
                  6 %   Example,
                  7 %       A = [1 2 3      B = rot90(A) = [ 3 6
                  8 %            4 5 6 ]                     2 5
                  9 %                                        1 4 ]
                 10 %
                 11 %   Class support for input A:
                 12 %      float: double, single
                 13 %
                 14 %   See also FLIPUD, FLIPLR, FLIPDIM.
                 15 
                 16 %   Thanks to John de Pillis
                 17 %   Copyright 1984-2010 The MathWorks, Inc. 
                 18 %   $Revision: 5.11.4.5 $  $Date: 2010/08/23 23:08:13 $
                 19 
             2   20 if ~ismatrix(A) 
                 21     error(message('MATLAB:rot90:SizeA'));
                 22 end
             2   23 if nargin == 1 
                 24     k = 1;
             2   25 else 
             2   26     if ~isscalar(k) 
                 27         error(message('MATLAB:rot90:kNonScalar'));
                 28     end
             2   29     k = rem(k,4); 
             2   30     if k < 0 
                 31         k = k + 4;
                 32     end
             2   33 end 
             2   34 if k == 1 
                 35     B = A(:,end:-1:1);
                 36     B = B.';
             2   37 elseif k == 2 
             2   38     B = A(end:-1:1,end:-1:1); 
                 39 elseif k == 3
                 40     B = A.';
                 41     B = B(:,end:-1:1);
                 42 else
                 43     B = A;
                 44 end