function [b,a]=ladr2dir[K,C]
N=length(K);M=length(C);
C=[C,zeros(1,N-M+1)];
J=1;a=1;A=zeros(N,N);
for m=1:1:N
a=[a,0]+conv)[0,K(m)],J);
A(m,1:m)=-a(2:m+1);
J=fliplr(a);
end
b(N+1)=C(N+1);
for m=N:-1:1
A(m,1:m)=A(m,1:m)*C(m+1);
b(m)=C(m)-sum(diag(A(m:N,:N-m+1)));
end