clear all; 
clc; 
%%%%%%%%%%%%define dimension of the parity check matrix%%%%%%%% 
rows=100; 
cols=200; 
h=gen_ldpc(rows,cols);%generates a 100 x 200 H matrix( the IG parity 
                      %check matrix) 
[newh,rearranged_cols]=rearrange_cols(h); 
% newh holds the rearranged version of H and rearranged_cols holds 
%the rearrangement order of columns 
%%%%%%%%%%%%Get A and B matrices %%%%%%%%%%%%%%%% 
for i=1:rows 
    for j=1:rows 
        A(i,j)=newh(i,j); 
    end 
end 
for i=1:rows 
    for j=rows+1:cols 
        B(i,j-rows)=newh(i,j); 
    end 
end 

%%%%%%%%%%%%%%message bits%%%%%%%%%%%%%%%%%%%%% 

%generate message bits randomly 
for i=1:cols-rows 
    s(i)=round(rand); 
end 
s=s';% make it a row vector 
%%%%%%% or load s from file %%%%type "help load" at matlab prompt for details 

%%%%%%%%%%%%%%get check bits( Eqn.5)%%%%%%%%%%%%%%%% 

d=mul_GF2(inv_GF2(A),B); 
c=mul_GF2(d,s); 
%%%%%%%%%%%%%%%%%form u'%%%%%%%%%%%%% 
u1=c; 
for i=rows+1:cols 
    u1(i)=s(i-rows); 
end 
%%%%%%%%%%%%%%% reorder u?to get the CW u %%%%%%%%%%%%%%%%%%% 
u=reorder_bits(u1,rearranged_cols); 
u
%%%%%%%%%%%%%%% u is the codeword to be transmitted %%%%%%%%%%%%%%%%%%%