function A=cps2a(C,P);
% Conversion of LPC cepstra to LPC coefficints (not very optimized...)
%
% Syntax: A=cps2a(C)
%      or A=cps2a(C,P)
%
% C is the matrix with vector of LPCC coefficients (without c0) in each 
%    column: [c(1) c(2) ... c(NBC)]'
% P is the desired number of LPCC coefficients without a0. (default NBC)
% P can not be > NBC
% A is matrix with a vector of P+1 LPC coefficients in each column (including
%    a0=1): [1 a(1) a(2) ... a(P)]'

[NBC,Nram] = size(C);
if nargin==1,
 P=NBC;
end

% alloc for A
A = zeros(P+1,NBC);
A(:,1) = 1; 

% the cycle
for ii=1:Nram, 
  c = [0; C(:,ii)]; % the vector completed  with zero so that we
                    % can use the code from prev function. 
  a=zeros(P+1,1);
  a(1)=1;

  for n=1:P,
    som=0;
    for k=1:n-1
      som=som+k/n*c(k+1)*a(n-k+1);
    end                                            % end de for k
    
    a(n+1)=-c(n+1)-som;
  end        
  A(:,ii) = a;
end