seek_sixcycle.m

ldpc编码

function [cycle_position_all find_six]=seek_sixcycle(H,p)
%clc;clear all;
%  H=[1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0;
%     0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0;
%     0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0;
%     0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0;
%     0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1;
%     1 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 1 0;
%     0 1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 1;
%     0 0 1 0 0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0;
%     0 0 0 1 0 0 0 0 0 1 0 0 1 0 0 0 1 0 0 0;
%     0 0 0 0 1 1 0 0 0 0 0 0 0 1 0 0 0 1 0 0;
%     1 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 1;
%     0 1 0 0 0 0 0 0 0 1 0 0 0 1 0 1 0 0 0 0;
%     0 0 1 0 0 1 0 0 0 0 0 0 0 0 1 0 1 0 0 0;
%     0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0;
%     0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0];
% dv=3;
% dc=9;
% p=12;
% S = [0     0     0     0     0     0     0     0     0;
%      0     5     2     6    11     1     8    10     7;
%      0     6     4     1     9     5     2     7     3];
% H=hcreat(H_origin,p,S)
[m,n]=size(H);
%S=[0 0 0 0;0 4 1 2;0 2 3 1];
cycle_position_all=[];find_six=0;
for l=1:m-p
    l;
    h_r=H(l,:);
    r_index=find(h_r);
    L_r=length(r_index);
    for i=1:L_r-1
        i;
        for j=i+1:L_r
            j;
            h_c=H(l+1:end,r_index(j));%取出第一行中第二个1所在的列，不包括本身
            c_index=find(h_c);
            c_index=c_index+l;
            L_c=length(c_index);
            for k=1:L_c
                h_r_two=H(c_index(k),:);%取出上述列中各个1所在的行作为第二行
                r_index_two=find(h_r_two);
                L_r_two=length(r_index_two);
                for i2=1:L_r_two
                    if r_index_two(i2)~=r_index(j)&&r_index_two(i2)~=r_index(i)%如果第二行中1所在的列不等于第二个1所在的列
                        h_c_two=H(l+1:end,r_index_two(i2));%取出第二行中1所在的列
                        c_index_two=find(h_c_two);
                        c_index_two=c_index_two+l;
                        L_c_two=length(c_index_two);
                        for j2=1:L_c_two
                            if c_index_two(j2)~=c_index(k)&&H(c_index_two(j2),r_index(i))==1
                                cycle_position=[l r_index(i);l r_index(j);c_index(k) r_index(j);c_index(k) r_index_two(i2);c_index_two(j2) r_index_two(i2);c_index_two(j2) r_index(i)];
                                cycle_position_all=[cycle_position_all cycle_position];
                                find_six=find_six+1;
                            end
                        end
                    end
                end
            end    
        end
    end
end