time   calls  line
                  1 function y = flipud(x)
                  2 %FLIPUD Flip matrix in up/down direction.
                  3 %   FLIPUD(X) returns X with columns preserved and rows flipped
                  4 %   in the up/down direction.  For example,
                  5 %   
                  6 %   X = 1 4      becomes  3 6
                  7 %       2 5               2 5
                  8 %       3 6               1 4
                  9 %
                 10 %   Class support for input X:
                 11 %      float: double, single
                 12 %
                 13 %   See also FLIPLR, ROT90, FLIPDIM.
                 14 
                 15 %   Copyright 1984-2010 The MathWorks, Inc.
                 16 %   $Revision: 5.9.4.5 $  $Date: 2010/08/23 23:08:00 $
                 17 
            55   18 if ~ismatrix(x) 
                 19   error(message('MATLAB:flipud:SizeX')); 
                 20 end
            55   21 y = x(end:-1:1,:);