function [A,C]=luFromClass(A)
% This is the decomposition we talked about in class.  Calling this
% function produces the upper triangular matrix U and a matrix of constants
% C.  
%
%Example useage:
% A=[1 2 -1;2 1 -2;-3 1 1];
% [U,L]=luFromClass(A);
%
% Exam problem:  Change the code below so that you get the lower triangular
% matrix L instead of the constant matrix C.  See page 86 for an example of
% what the example above should give you.

[m,n]=size(A);

C=zeros(m,n);

for k=1:n-1
    for j=k+1:n
        if A(k,k)~=0 %Be sure we're not dividing by zero
           C(k,j)=-A(j,k)/A(k,k);
           A(j,:)=C(k,j)*A(k,:)+A(j,:);
        else
            error('Zero pivot in Z');
        end
    end
end