backsub.m

用matlab写的一些数值算法

function  x = backsub(U, c)
% Back substitution to solve Ux = c

% Version 11.12.2003.  INCBOX

n = length(c);    
x(n,1) = c(n) / U(n,n);  % col. vector of length n
for  i = n-1 : -1 : 1
  x(i) = ( c(i) - U(i,i+1:n)*x(i+1:n) ) / U(i,i);
end