function [cps,R]=all_pole_ifft(s,LPC_ORDER,CPS_ORDER);
% ALL_POLE modeling, [cps,R]=all_pole_ifft(s,LPC_ORDER)
% everything hard-wired inside. Reads mel fb from ~/matlab/fbanks/
% can eventually output also the dct
% repeats st and last channel and does a real ifft. 

load /u/honza/matlab/fbanks/mfb
N=size(mfb,2);

S = abs(specgram(s,256,8000,hamming(200),120)).^2;
Nfr = size(S,2);

% tests with preemphasis on the spec:
%qq = abs(freqz([1 -0.97],1,129)).^2;  
%S = S .* (qq * ones(1,Nfr)); 

fbout = mfb' * S;       

% cube root
fbout3 = fbout .^ (1/3);
%fbout3 = log(fbout); 

% ifft - better do it in a cycle.
R = zeros(2*(N+1),Nfr); 
for ii=1:Nfr,
  repeated = [fbout3(1,ii); fbout3(:,ii); fbout3(N,ii)]; 
  x = [repeated; repeated(N+1:-1:2)]; % flip for the ifft
  X = real(ifft(x));
  R(:,ii) = X;  %pause 
end

% now all-pole, do also gain acc to definition 
cps = zeros(CPS_ORDER,Nfr); %aux=[];
for ii=1:Nfr;
  r = R(1:LPC_ORDER+1,ii); %figure(1); plot (r); grid
  a = levinson(r); 
%  aux = [aux a(2:LPC_ORDER+1)'];
  c = a_to_cepst (a',CPS_ORDER-1);
  gain2 = r'*a';
  c(1) = log(gain2);
%  c(1) = log(r(1));
  cps(:,ii) = c;
%  pause
end