t = A*q(:,j-1) - alfa(j-1)*p(:,j-1);
   if ort>0, for i = 1:j-1, t = t - t'*p(:,i)*p(:,i);
beta(j) = norm(t);
p(:,j) = t/beta(j);
t = A'*p(:,j) - beta(j)*q(:,j-1);
   if ort>0, for i = 1:j-1, t = t - t'*q(:,i)*q(:,i);
alfa(j) = norm(t);
q(:,j) = t/alfa(j);
