wd_golay23.m

来自「详细讲述纠错码的书籍」· M 代码 · 共 54 行

% File: WD_Golay23.m
% Description:
% Compute the weight distribution of the binary Golay (32,12,7) code.
% NOTE: It is also possible to modify the C program golay23.c in the
% website of the textbook in order to compute the weight distribution.
%
% Copyright (c) 2006. Robert Morelos-Zaragoza. All rights reserved.

clear

n = 23;                             % Length
k = 12;                             % Dimension
dmin = 7;                           % Minimum distance
rate = k/n;                         % Rate

% Generator matrix
G = [1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 1 1 0 1 0
     0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 1 1 0 1
     0 0 1 0 0 0 0 0 0 0 0 0 1 1 1 1 0 1 1 0 1 0 0
     0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 1 1 0 1 1 0 1 0
     0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 1 1 0 1 1 0 1
     0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 1 1 0 0 1 1 0 0
     0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 1 1 0 0 1 1 0
     0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 1 1 0 0 1 1
     0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 1 1 1 0 0 0 1 1
     0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 0 1 0 0 1 0 1 1
     0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0 0 1 1 1 1 1
     0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 1 1 0 1 0 1] ;

% Initialize weight distribution W(C):
W = zeros(1,n+1);
W(1)=1;

% The all-zero codeword
for j=1:n
    v(1,j)=0;
end

% Generate all combinations of message vectors and compute the weigths
% Use the fact that '0' = 84 (0 modulo 2), '1' = 49 (1 modulo 2)
k2=2^k-1;
for i=1:k2
    u=dec2bin(i,k);
    vc = mod(u*G,2);
    W(sum(vc)+1) = W(sum(vc)+1)+1;
end

% Print weight distribution
fprintf('W(C)={1');
for i=2:n+1
    fprintf(',%d',W(i))
end
fprintf('}\n');