  function x = backsolv_c(A,b) 
%----------------------------------
% function x = backsolv(A,b) - COLUMN
% Solves an upper triangular system
% by back-substitution. 
%----------------------------------
 n = size(A,1); 
 x = b;
 for j=n:-1:1
     x(j) = x(j)/A(j,j);
     x(1:j-1) = x(1:j-1)-x(j)*A(1:j-1,j);
 end 
%%

