rearrange_cols.m

本源码用于LDPC的编码算法。运用LDPC编码的基本原理

function [b,rearranged_cols]=rearrange_cols(A)
%[b,rearranged_cols]=rearrange_cols(A) Rearrange the columns of the parity
%check matrix to get non singular A matrix

dim=size(A);
rows=dim(1);
cols=dim(2);

newA=A;
clear A

for i=1:rows
   rearranged_cols(i)=0;
end

  for i=1:rows
      if newA(i,i)==0
         k=i+1;
         if k<cols
         
             while newA(i,k)==0
               k=k+1;
            	if k==cols
               	break
            	end
         	end 
            pack
   
         		temp=newA(1:rows,k);
         		newA(1:rows,k)=newA(1:rows,i);
               newA(1:rows,i)=temp;
               
               rearranged_cols(i)=k;

                clear temp;

         end
      end
      for j=1:rows
        if j~=i
            if newA(j,i)==1
               newA(j,1:cols)=xor(newA(i,1:cols),newA(j,1:cols));
            end 
         end
     end


end   

   b=newA;
   clear newA