%LU razcep - demonstracija algoritma 2.4.1

n = 4;
A = rand(n)
     b = [1:n]';
Aorig = A;
borig = b;

alg251

for i=1:n-1, temp = b(i); b(i) = b(p(i)); b(p(i)) = temp; end
L = tril(A,-1) + eye(n);
U = triu(A);
alg221
alg222
ostanek = Aorig*b - borig
nost = ostanek/eps