rel_prime.m

Generates Alist format files for SFT LDPC codes

function [r,product] = rel_prime(m)
%find_order(j,m)

r = -1;
z = m;
count = 1;
product = 1;
l1 = factor(m);
size1 = size(l1);
relatively_prime = 1;

while(z >= 1)
   l2 = factor(z);
   size2 = size(l2);
   for w=1:size1(1,2)
       for n=1:size2(1,2)
          if l1(w) == l2(n)
              relatively_prime = 0;
          end
       end
   end
    if relatively_prime == 1
       r(1,count) = z;
       product = product*(1-1/z);
       count = count + 1;
   end
    z = z-1;
    relatively_prime = 1;
end

product = product*m;
%if count ~= 1
 %   a = r(1,1);
 %end
    %else
    %a = r(1,2);
    %end