dirnums.m

very good matlab of Monte carlo

%DIRNUMS		 calculates the direction numbers
%m=dirnums(poly,k,m)
%	for the sobol sequence given
%	poly - 1/0 vectors indicating the indices - descending order including leading and following 1
%	k - the required number of direction numbers
%	m - the initial d direction numbers
function m=dirnums(poly,k,m)

%d=3,a1 =1,a2=0
d=length(poly)-1;
poly=poly(2:end-1);
for i=d+1:k
   m(i)=bitxor(2^d*m(i-d),m(i-d));	%last 2 element
   for j=1:(d-1)
      m(i)=bitxor(2^j*poly(j)*m(i-j),m(i)); %binary or is commutative and associative
  end;
   
end;