19
Matlab Code (Without Pivoting)
function a=rlu(a)
[m,n]=size(a);
mn = min(m,n);
if mn > 1
nl =
bitshift(mn,-1);
% lu on left part
a(1:m,1:nl)= rlu(a(1:m,1:nl));
% trangular solve
a(1:nl,nl+1:n) =
(tril(a(1:nl,1:nl))-diag(diag(a(1:nl,1:nl)))+eye(nl))\a(1:nl,nl+1:n);
% matrix multiple
a(nl+1:m,nl+1:n) = a(nl+1:m,nl+1:n) -
a(nl+1:m,1:nl)*a(1:nl,nl+1:n);
% lu on right part
a(nl+1:m,nl+1:n) = rlu(a(nl+1:m,nl+1:n));
else
% mx1 case
a(2:m,:) = a(2:m,:)/a(1,1);
end
return
No iteration loop!