matlab's rref function modified to operate in gf(2)

g2rref.m

% This is a modified version of matlab's building rref which calculates
% row-reduced echelon form in gf(2).  Useful for linear codes.
% Tolerance was removed because yolo, and because all values
% should only be 0 or 1.  @benathon

function [A] = g2rref(A)
%G2RREF   Reduced row echelon form in gf(2).
%   R = RREF(A) produces the reduced row echelon form of A in gf(2).
%
%   Class support for input A:
%      float: with values 0 or 1
%   Copyright 1984-2005 The MathWorks, Inc. 
%   $Revision: 5.9.4.3 $  $Date: 2006/01/18 21:58:54 $

[m,n] = size(A);

% Loop over the entire matrix.
i = 1;
j = 1;

while (i <= m) && (j <= n)
   % Find value and index of largest element in the remainder of column j.
   k = find(A(i:m,j),1) + i - 1;

   % Swap i-th and k-th rows.
   A([i k],j:n) = A([k i],j:n);
   
   % Save the right hand side of the pivot row
   aijn = A(i,j:n);
   
   % Column we're looking at
   col = A(1:m,j);
   
   % Never Xor the pivot row against itself
   col(i) = 0;
   
   % This builds an matrix of bits to flip
   flip = col*aijn;
   
   % Xor the right hand side of the pivot row with all the other rows
   A(1:m,j:n) = xor( A(1:m,j:n), flip );

   i = i + 1;
   j = j + 1;
end

Hi,
Thank you for providing this efficient well working code. I was dealing with this problem for a while and your code helped me a lot. However, I need the result to be in the form I have sent you the picture for and the result that I get using your code is not like that. can you help me with that? thanks